December 29, 1961
electronics
A McGraw-Hill Publication 75 Cents
Photo at right SONAR FOR FROGMEN
Locates underwater objects, p 37
MICROCIRCUIT ‘SLIDE RULE’
Molecular circwut multiplies and divides, p 40
DIGITAL TRACKING Keeps radar
locked on target, p 46
CAMERA PERISCOPE For cathode-
ray-tube : = HOIR SOGuY NNV
‘ bie pane 4 — LS iSuId 8 ¢I¢ photography, p 51 . c ey Ld2@ WIuor 0"
Sy we eee PRs EE
1000-Mc Standard K&S
Short-term and long-term stabilities comparable to the best crystal controlled standards available . . . at less than 24 the price!
Outputs from 100c to 1000 Mc at decade intervals, plus 60c, 400c, and 5 Mc... more outputs than any other commercial unit provides.
Two big reasons why you get so much for so little money in a G-R Frequency Standard:
7 NO militarization .. . why pay more for extreme shock and fungus protection — it doesn’t make a standard more stable nor does it contribute to laboratory usefulness.
2 Years of experience . . . this standard’s ancestors include the first commercially-available crystal-controlled pri- mary frequency standard.
5-Mc fifth-overtone crystal and
Long-term Stability: 5 parts in 10'® per day, two-stage oven.
averaged over 10 days after 60 days
; : , operation. Short-term Stability: 1 part in 10! per min.,
using 1-sec samples. Syncronometer resolution is better than +0.2 msec for time comparisons consist- ent with stability of sky-wave signals from WWYV and other stations.
Harmonics for measurements well be- yond X-band can be produced.
oe from 100¢ to 1000 Mc at decade 10-kc and 100-kc square wave available for re triggering purposes. Low Noise: pulse-type dividers give fail-
safe operation and minimize phase noise below 5 Mc; phase-locked crystal oscilla- tors provide clean signals above 5 Mc —
Emergency Power Supply available as an accessory.
Optional Plug-in Units provide 400- and
f-m noise less than 1 part in 10°. 60-cycle outputs.
Type 1120-AH 1000-MC Frequency Standard... $6450 complete
Includes, from top to bottom, 1103-B Syncronometer . . . $900 1113-A Standard Frequency Oscillator . . . $1550
1114-A Frequency Divider . . . $950
1112-A Standard Frequency Multiplier (1,10,100 Mc) . . . $1450 1112-B Standard Frequency Multiplier (1000 Mc) . . . $1360 plus rack and all interconnection provisions.
also available for
automatic frequency measurement 1130-A Digital Time and Frequency Meter “The Counter With A Memory”’.
Oe ee mn ne Ae
Write for information regarding a system for frequency measurements to one part in 10!'.
GENERAL RADIO COMPANY
WEST CONCORD, MASSACHUSETTS
WEW YORK, WOrth 4-2722 CHICAGO PHILADELPHIA ‘ in Ri ; Oak Park Abington District Office in Ridgefield, N. J. 7 yeh os Village 8-9400 HAncock 4-7419
WASHINGTON, D.C. SYRACUSE SAN FRANCISCO Silver Spring Syracuse Los Altos JUniper 5-1088 GLenview 4-9323 WHitecliff 8-8233
LOS ANGELES ORLANDO, FLA. IN CANADA Los Angeles Orlando Toront
0 HOllywood 9-6201 GArden 5-4671 CHerry 6-2171
December 29, 1961
electronics
A McGraw-Hill Publication 75 Cents
W. W. MacDONALD, Editor
J. M. CARROLL, Managing Editor SENIOR EDITORS: Samuel Weber, George W. Sideris. SENIOR ASSO- CIATE EDITORS: William E. Bushor, Michael F. Wolff. ASSOCIATE EDI- TORS: Michael F. Tomaino, Sylvester P. Carter, William P. O’Brien, John F. Mason, Thomas Emma, Sy Vogel, leslie Solomon, M. M._ Perugini, George J Flynn, Laurence D. Shergalis. ASSISTANT EDITORS: Nilo Lindgren, Stanley Froud, Stephen B. Gray, Roy J. Bruun, George V. Novotny, Leon H. Dulberger. REGIONAL EDITORS: Harold C. Hood Pacific Coast, Los Angeles), Thomas Maguire (New England, Boston), Cletus M. Wiley (Midwest, Chicago). ART DIRECTOR: Harry Phillips; Howard R. Berry. PRODUCTION EDITOR: John C. Wright, Jr. EDITORIAL ASSIST- ANTS: Gloria J. Meurer, Bernice Duffy, lorraine Rossi, Virginia T. Bastian, Lynn Emery, Lavra W. Smith, Bette H. Snyder, Rosemary Abbruzzese, Judy Haskins.
JAMES GIRDWOOD, Publisher
Scuba diver walks from sea with sonar set that enables him to locate objects in murky waters. Transistor unit has 120 yards
range. See p 37 COVER
ITERATIVE TECHNIQUES Widen Applications of Analog Com- puters. New equipment exhibited at Eastern Joint Computer Conference
Gondola Makes Dry Runs in Space. Simulator performs all phases of manned space flight missions
Engineer Supply Drops Sharply. Demand is up, but fewer students enroll in engineering colleges
Computer Controls Parking Garage. One attendant can get 27 cars parked in 10 minutes
OSCAR SATELLITE Orbited by Amateur Radiomen. Group hopes to build relay capability into future satellites
PORTABLE SONAR FOR FROGMEN. Uses audio tone as range indicator. I. R. Colldeweih, E. L. Walls and R. D. Lee
MICROCIRCUIT SLIDE RULE Multiplies and Divides. Diodes and transistors are fabricated on single silicon substrate. H. C. Lin, C. E. Benjamin, P. W. Smith and B. S. Aronson
Illumination Stabilizer for Photosensing System. Transistors are used in feedback loop. J. R. Dyke
DIGITAL TRACKING: Automatic Radar Ranging Control. Locks fast to target and provides highly accurate data. D. L. Nepveux
Camera Periscope for Crt Photography. How to design optics for display. D. Levine
Crosstalk Components and Materials Comment Production Techniques Electronics Newsletter New on the Market Washington Outlook Literature of the Week Meetings Ahead People and Plants
Research and Development Index to Advertisers
STRENGTH IN THE
MIDDLE
e223 EY
Tarzian's new 6-amp silicon rectifier strengthens your ability to select the right rectifier for every medium current requirement.
The new line-up gives you a wider choice of units—2, 6, 10, 12, and 20-amp —each delivering quality performance at traditional Tarzian prices. Each unit gives you a choice of ratings from 100 to 600 PIV, in increments of 100... from 70 to 420 maximum RMS voltage, in incre- ments of 70.
You'll find additional specifications spelled out in the new Tarzian catalog. Free copies, and free application engi- neering service, are yours for the asking. Ask!
World’s Leading Manufacturers of TV and FM Tuners « Closed Circuit TV Systems e Broadcast Equipment « Air Trimmers «
FM Radios « Magnetic Recording Tape « Semiconductor Devices
SARKES TARZIAN
iInc., SEMICONDUCTOR DIVISION BLOOMINGTON, INDIANA In Canada, 700 Weston Rd., Toronto 9 Export: Ad Auriema, Inc., New York
2 CIRCLE 2 ON READER SERVICE CARD
NEW
TARZIAN 6-AMP
RECTIFIER
electronics
Arnold Pulse Transformer Cores ate individually tested
under actual pulse conditions
Here’s technical data on
ARNOLD SILECTRON CORES
Bulletin SC-107 A
. this newly- reprinted 52-page bulletin contains design information on Arnold Tape Cores wound from Silectron (grain-oriented silicon steel). It includes data on cut C and E cores, and uncut toroids and rectangular shapes. Sizes range from a fraction of an ounce to more than a hundred pounds, in standard tape thicknesses of 1, 2, 4 and 12 mils.
Cores are listed in the order of their power- handling capacity, to permit easier selection to fit your requirements, and curves showing the effect of impregnation on core material properties are included. A valuable addition to your engineering files—write for your copy today.
ADDRESS DEPT. E-12
December 29, 1961
The inset photograph above illus- strates a special Arnold advantage: a 10-megawatt pulse-testing installa- tion which enables us to test-prove pulse cores to an extent unequalled elsewhere in the industry.
For example, Arnold 1 mil Silectron “C” cores—supplied with a guaran- teed minimum pulse permeability of 300—are tested at 0.25 microseconds, 1000 pulses per second, at a peak flux density of 2500 gausses. The 2 mil cores, with a guaranteed minimum pulse permeability of 600, receive standard tests at 2 microseconds, 400 pulses per second, at a peak flux
density of 10,000 gausses.
The test equipment has a variable range which may enable us to make special tests duplicating the actual operating conditions of the trans- former. The pulser permits tests at .05, .25, 2.0 and 10.0 microsecond pulse duration, at repetition rates varying anywhere from 50 to 1000 pulses per second.
This is just another of Arnold's facilities for better service on mag- netic materials of all description. @ Let us supply your requirements. The Arnold Engineering Company, Main Office & Plané, Marengo, Il.
wARNOLD
SPECIALISTS in MAGNETIC MATERIALS
BRANCH OFFICES and REPRESENTATIVES in PRINCIPAL CITIES Find them FAST in the YELLOW PAGES
CIRCLE 3 ON READER SERVICE CARD
electronics December 29, 1961 Volume 34 No. 52
a Published weekly, with Electronics Buyers’ Guide and Reference issue, as part of the subscription, by McGraw-Hill Publishing Company, Inc. Founder: James H. McGraw (1860-1948).
Title ® registered U.S. Patent Office; Copyrighted © 1961, McGraw-Hill Publishing Company, Inc. All rights reserved, including the right to repro- duce the contents of this publication, in whole or in part.
Executive, editorial, circulation and advertising offices McGraw-Hill Build- ing, 330 West 42nd Street, New York 36, N. Y. Telephone Longacre 4-3000. Teletype TWX N.Y. 1-1636. Cable McGrowhill, N. Y. PRINTED IN AL-
BANY, N. Y.; second class postoge paid.
OFFICERS OF THE PUBLICATIONS DI- VISION: Nelson L. Bond, President; Shelton Fisher, Wallace F. Traendly, Senior Vice Presidents; John R. Calla- ham, Vice President and Editorial Di- rector; Joseph H. Allen, Vice President ond Director of Advertising Sales; A. R. Venezian, Vice President and CLircu- lation Coordinator; Daniel F. Crowley, Vice President and Controller.
OFFICERS OF THE CORPORATION: Donald C. McGraw, President; Hugh J. Kelly, Harry L. Waddell, Executive Vice Presidents; L. Keith Goodrich, Executive Vice President and Treas- vrer; John J. Cooke, Vice President and Secretary.
Subscriptions are solicited only from those actively engaged in the field of the publication. Position and com- pony connection must be indicated on orders. Subscription rates: United States and Possessions, $6.00 one year; $9.00 two years; $12.00 three yeors. Canade, $10.00 one year. All other countries $20.00 one year. Single Copies, United States and Possessions and Canada 75¢; Buyers’ Guide $3.00; Single copies all other countries $1.50; Buyers’ Guide $10.00.
THE PUBLISHER, UPON WRITTEN RE- QUEST FROM ANY SUBSCRIBER TO OUR NEW YORK OFFICE, AGREES TO REFUND THAT PART OF THE SUB- SCRIPTION PRICE APPLYING TO COPIES NOT YET MAILED.
Subscribers: Please address all cor- respondence, change of address notices, subscription orders or com- plaints to Fulfillment Manager, Elec- trénics, at above address. Change of oddress notices should provide old os well os new address, including postal zone number if any. If pos- sible, attach address label from re- cent issue. Allow one month for change to become effective.
Postmaster: Please send Form 3579 to Fulfill t M ger, Electronics, 330 West 42nd Street, New York 36,
New York.
©:
Audited Paid Circulation
CROSSTALK
Shakeup, Not Shakeout
WE’RE WONDERING what happened to the big shakeout in the electronics industry that so-called experts have been predicting for the past couple of vears. As this vear winds up and the reports come in we still don’t see this major holocaust.
We see changes in technology. We see new patterns of sales and distribution. We see new markets opening up. The sight of the nation’s cities littered with the corpses of electronics com- panies, however, is something we don’t see... nor do we expect to.
Against this bullish attitude, adequately bolstered from within our industry, we do see areas where glamor dazzled reason. This, however, has been on a small scale in terms of the entire industry.
In all likelihood, fingers that were burned would have gotten that way had they been handling electronics, apple pies or costume jewelry.
We cannot, from anything we know, extrapolate a picture of companies falling by the wayside in droves. The declines within the electronics industry derive from changing technology. What some observers-from-without fail to realize is that tech- nological improvement does not create voids. It fills needs. For each category of equipment that declines from the market, a new category or class of categories comes into being.
The manufacturer sensitive to the changing technologies of this industry will change with it and prosper. The inflexible management, seeing no view but the one immediately before it, will bulldog its way to oblivion and not be missed by the industry at large.
The more doomsday predictions we hear about the electronics industry the more we recall Mark Twain’s quip following the mistaken appearance of his obituary in a small town newspaper. “The reports of my death have been grossly exaggerated !”
Coming In Our January 5 Issue
SUMMING UP. For several years, throughout the industry, U. S. our way of editorially greeting and foreign government officials. the new year has been to take a Finally, they condensed the facts long-range look at electronics into 32 pages and picked an ap-
market opportunities. This year, we assigned four men—backed up by our regional editors—to hunt up fresh, authoritative sta- tistics, evaluation and _ predic- tions. They used the News Sys- tem (North, East, West, South), contacting top executives
propriate title, “Our Growing Markets.”” Appropriate because they found that wide-awake com- panies with a talent for research, development and production will find many opportunities for new products and bigger sales in the years ahead.
electronics
“Is that the new Norton
You bet it is!
It’s dog-eared and marked up because it’s in constant use by men who want better materials — high purity refractory materials which will stand up under the most extreme thermal, mechanical, chem- ical, electrical, and radioactive conditions.
This valuable, well-illustrated reference describes in detail the many Norton re- fractory materials which are helping to solve widely different product and proc- essing problems. Uses range from aiding
December 29, 1961
eZ Ll
chemical reactions to stopping neutrons, handling molten metals, protecting rocket engines — and taming lightning.
Catalog lists physical, chemical and electrical properties of CRYSTOLON* Sili- con Carbide, ALUNDUM* Aluminum Oxide, MAGNORITE* Magnesium Oxide, NORBIDE* Boron Carbide, and Fused Zirconia. It’s thought-provoking...areal “idea-starter!”
You may well profit from this book in solving your own processing problems. No charge or obligation, of course, write for “Norton Refractory Grain,”
NorRTON ComPANY, Refractories Division, 692 New Bond St., Worcester 6, Mass.
*Trade-Marks Reg. U.S. Pat. Off. and Foreign Countries
(NoRTONy
REFRACTORIES Crystallizing ideas into products
CIRCLE 5 ON READER SERVICE CARD
¥ a SSeS BES &
SPRAGUE PIEZO- ELECTRIC CERAMIC ELEMENTS
ELEMENTS FOR ALL _ APPLICATIONS = AS WELL AS COMPLETE TRANSDUCER ASSEMBLIES FOR MOST APPLICATIONS, SUCH AS UNDERWATER SOUND AND VARIOUS ORDNANCE AND MISSILE —
ae
Bi be.
Te eae
e _
Samba
Oe
ENE EP AMIS
Sea
Sprague-developed mass cauhidaties and quality-control techniques assure lowest possible cost consistent with utmost quality and reliability. Here too, complete fabrication facilities permit prompt production in a full,
wide range of sizes and shapes. Look to Sprague for today’s most advanced ceramic elements — where continuing intensive research prom- ises new material with many proper- ties extended beyond present limits. YOUR INQUIRIES
ee ar ARE INVITED
oa) WRITE FOR _= = LITERATURE SPRAGUE ELECTRIC COMPANY
35 Marshall Street, North Adams, Mass.
SPRAGUE
THE MARK OF RELIABILITY
CIRCLE 6 ON READER SERVICE CARD
COMMENT
Proprietary Rights
I want to congratulate you on the excellent editorial on proprie- tary rights that appeared in the Oct. 27 issue (p 98).
I have personally been faced with this problem on a good many occa- sions, particularly when I was with Aircraft Radio Corporation. I think one point that I might add, that possibly has not been stressed enough in your editorial or other articles on this subject, although it is usually mentioned, is that a sup- plier of electronic equipment to the military must assume that the mili- tary will need drawings and speci- fications for certain replacement parts in order to catalog them prop- erly. They will also need informa- tion for the maintenance and over- haul of the equipment and this means that a certain minimum number of drawings and specifica- tions must be supplied, whether the manufacturer wants to or not.
The manufacturer cannot assume that the equipment is to be deliv- ered and then be forgotten about
Transistor Circuit Design
forever. If arrangements can be made with the Contracting Officer to supply specific drawings for the above purposes only, I think the manufacturer will have done his duty and the military will have re- ceived all the information that they really need for operation and main- tenance. A. W. PARKES, JR. President Ballantine Laboratories, Inc. 3oonton, New Jersey
Plasma Engineering
I think your articles [p 47, July 14; p 33, Aug. 4; p 29, Sept. 1] gave a concentrated but compre- hensive picture of current plasma physics research. The outlook for industrial plasma research in the U. S. was especially interesting.
In Uppsala, our work on low- inductance capacitors and very fast discharges continues. We will keep you informed about results.
LARS HOGBERG Fysiska Institutionen Uppsala, Sweden
In the Nov. 3 issue (p 48) there were errors in the article, Computer-
Derived Curves Simplify Transistor Circuit Design,
Martin.
In the sentence following Eq. 7 (p 49), change R,/R,
by D. McLarin, of
= $to R,/R, = &
Graph F (p 50) should be labeled R,/R, = 3, rather than R,/R, =
In Eq. 17 (p 51), Z,,
is stated incorrectly.
One term of the numerator
is missing, and part of the denominator is placed above Eq. 18 in the next column, Equations 17 and 18 should be as follows:
Zin —
tRin R, + Rin
ty = te zs
The sentence following Eq.
igh Ry (1 + joC rs) + Riley (1+ Be) RiR2 (1 + jwCeR;) + (Ri + R2) [Rs (1 + 8) + hie 1 + joCrRs))
(17)
(18)
30 (p 54) should be: Substituting Eq. 17
and 1/eC, in Eq. 30, rather than 1/oC.,,. Equations 31 and 32 (p 54) will be in error due to the error in Eq. 17. Equations 31 and 32 should be as follows:
1 RiRz thie + wCrlishie + Ra VL + B2)}
(31)
wl, RyR2(1 + wR» + (R, + RD IR: 1 + fe) + hie 1 + @CoRs)]
co. — Riles (1 + wCoRs) + (Ri 4 Seni
Equation 34 (p 54) should be
] Rihie
we Ra + Ris
The Martin Company Orlando, Florida
- Rs) [Rs (A + 2) +h; e(l + wR) | wR, R. [hie + wl "2Rshie + R; (i + Bo )}
(32)
STANLEY C. LOGAN Information Services
electronics
10,000 VARIATIONS...
all stamped with the T-MARK of total reliability
Other spring fasteners may Jook like Tinnerman SPEED NUTS. But only those stamped with the T-mark really are SPEED NuTs, made to Tinnerman’s high, precise standards of reliability. Tinnerman quality controls are the most stringent in the industry. And only Tinnerman stocks a half-billion SPEED NuTS... is tooled to turn out 10,000 variations
... develops 25 new designs each week. Protect your product’s good name by insist- ing on genuine SPEED Nuts. Stamped with the Tinnerman “T”—the mark of total reliability. Tinnerman Products, Inc., Department 12, Box 6688, Cleveland 1, Ohio.
CANADA: Dominion Fasteners Ltd., Hamilton, Ontario. T j N i E oa M A a
GREAT BRITAIN: Simmonds Aerocessories Ltd., Treforest, Wales. FRANCE: Simmonds S.A., 3 rue Salomon de Rothschild, Suresnes (Seine).
Cra, iy Vi @ aS WOO jj ‘), V,/] GERMANY: Mecano Simmonds GMBH, Heidelberg. CYQ266 / CLL)
Look for the Tinnerman “T”
December 29, 1961 CIRCLE 7 ON READER SERVICE CARD
MEASURE
VOLTAGE to 500 KC
WITH YOUR
DC
VOLTMETER
electronics
NEW @ 457A AC TO DC CONVERTER
New ® 457A AC to DC Converter lets you inexpensively measure ac voltage, 50 cps to 500 KC, with the ease and high resolution of a dc digital voltmeter.
The average-responding 457A permits ac measurements to +0.3% of reading +0.001 v to 50 KC and +0.75% +0.001 v to 500 KC. This accuracy permits you to read ac voltages on a dec digital volt- meter (such as the # 405BR/CR) with three digits resolution.
Waveform errors are minimized by this new converter. The dc output of the 457A is always between 0 and 1 volt for up to full scale input. Full scale is selected manually in decade ranges. Your measurement convenience is further increased with overranging by more than 2 to 1 and an input impedance of 1 megohm.
The 457A Converter can be used with an # 560 Series Digital Re- corder, plus a digital voltmeter, to provide a permanent printed record. Either the 457A analog or digital voltmeter output data is suitable for other data logging equipment. The digital data may be transferred, for example, to card or tape punches.
New ® instrument modular packaging permits easy stacking of instruments on the bench, and simple conversion to rack mount.
Specifications
input Range: 0 to 300 v rms, in 4 decade ranges cor- responding to 1, 10, 100 and 1,000 v rms full scale.
50 cps to 500 KC
+0.3% of reading +1 mv, 50 cps to 50 KC; +0.75% +1 mv, 50 KC to 500 KC.
0 to 1.0 v dc, responding to average value of ac input, with output cali- brated as rms value of sine wave.
Output Impedance: 10,000 ohms.
Input Impedance: 1 megohm, shunted by 30 pf.
Size: 16%4” wide, 3%” high, 1344” deep.
Weight, 12 Ibs. $350.00
Frequency Range: Accuracy:
Output:
Price:
@ DEPENDABLE AUTOMATIC DIGITAL VOLTMETERS
& 405BR/CR Digital Voltmeter
Ideal for use with the 9 457A AC to DC Converter, the ® 405BR/CR Digital Voltmeters feature auto-
matic ranging, simple touch-and-read measurement and bright, clear readout. By using the # 405 in conjunction with the 457A, you can read ac voltages on the 405 to three digits with an overall accuracy of +0.4% of reading +0.001 v to 50 KC, +0.75% of reading +0.002 v to 500 KC. The ® 405BR and CR are identical except that the 405CR includes (a) provision for external sam- pling command, (b) digital recording outputs, plus (c) reading hold-off capability, (d) print command when overranging, and (e) remote readout outputs.
Specifications
Ranges: 0.001 to 999 v dc, 4 ranges. Presentation: 3 significant figures, polarity indicator. Accuracy: +0.2% of reading +1 count. Ranging Time: 0.2 sec to 2 sec. input Impedance: 11 megohms to dc, all ranges. Response Time: Less than 1 sec. AC Rejection: 3 db at 0.7 cps; min. 44 db at 60 cps. Size: 7” high, 19” wide, 13%” deep
behind panel. Weight, 26 Ibs.
Price: @ 405BR, $850.00; @ 405CR, $925.00.
FOR EVEN GREATER SYSTEMS FLEXIBILITY, USE DYMEC 2401
INTEGRATING DIGITAL VOLTMETER!
DY-2401 integrating Digital Voltmeter
Unique flexibility for simple and complex systems applications is yours with the Dymec 2401 Integrating Digital Voltmeter, which effectively eliminates the effects of noise and hum by reading the average value of voltage applied over a definite, selected sample period. Range, sample period and sample rate are externally pro- grammable. Applications are further extended by the nature of the 2401, actually a voltage-to-frequency converter, combined with a 300 KC electronic counter.
Equally versatile in systems application is the Dymec Model 2410
Multi-Converter (not shown) , which converts ac volts, resistance
and dc volts to a proportional dc voltage with i volt nominal full- scale output. $1,975.00.
Call your Hewlett-Packard /Dymec representative today for further information or for a demonstration on your bench.
HEWLETT-PACKARD COMPANY
1091C Page Mill Road Palo Alto, California, U.S.A. Cable “HEWPACK” DAvenport 6-7000
Field representatives in all principal areas
December 29, 1961
Specifications
DC Voltage Ranges: +0.1, 1, 10, 100, 1,000 v nominal full scale.
0.05% nominal.
Greater than 0.01%/day, 1 v range and above.
1 megohm on 1 v and higher ranges, 100,000 ohms on 0.1 v range.
$3,750.00.
Overall Accuracy: Stability:
Input Impedance:
Price:
Data subject to change without notice. Prices f.0.b. factory.
HEWLETT-PACKARD S. A. Rue du Vieux Billard No.1 _ Geneva, Switzerland Cable “HEWPACKSA” Tel. No. (022) 26. 43. 36
CIRCLE 9 ON READER SERVICE CARD
UNRETOUCHED PHOTOGRAPHS MAGNIFIED 424 TIMES
FLIP-FLOP GATE HALF-SHIFT REGISTER
“F" Element “G”" Element “S" Element
HALF-ADDER BUFFER COUNTER ADAPTER
“H" Element “B” Element “Cc” Element
are a compatible set of integrated digital functional blocks in which transistors and
resistors are diffused via the Planar proc- ess into a single, monolithic chip of silicon. This family of functional elements is sufficient to efficiently fabricate a com- puter logic section. No other components are required.
They are designed to operate in a full military environment, over a temperature range of —55 degrees C to +125 degrees C. When integrated into a computer, they will operate at 1 mc clock rates over the above temperature range.
Micrologic elements are designed primarily to permit highly reliable data processing logic at very low cost. They make possible a simplified approach to the job and hence greatly reduce the lead time to the prototype computer.
The cost savings are to computer manufacturers and the computer user. The choice of the elements and the nature of the package, are great factors in the tota! cost reduction associated with the reliability, maintainability, repairability, logis- tics, and training.
The size reduction (one order of magnitude) gained with Micrologic is an important by-product of the main objectives of
the program.
EL eae IMMEDIATE AVAILABILITY E™y All 6 Micrologic elements are available now for immediate vol- - } FR Cc ei i LD
ume delivery. Contact your Fairchild Field Sales Office.
RE ERE SE: 90% COST REDUCTIONS SEMICONDUCTOR IN LOGIC DESIGN & ASSEMBLY 545 WHISMAN ROAD, MOUNTAIN VIEW, CALIF.- YORKSHIRE 8-816] - TWX: MN VW CAL 853
° . i A DIVISION OF FAIRCHILD CAMERA AND INSTRUMENT CORPORATION Micrologic elements can cut logic system design and assembly costs up to 90%; space requirements up to 95%; power needs up to 75%. These savings are made possible through simplified lay- GENERAL SPECIFICATIONS FOR MICROLOGIC ELEMENTS
outs, standard handlings of TO-5 type packages, fewer inter- Speed * 50 nsec. delay per stage for all
board connections, single clocks, one power supply. pecan ee mine
Power * 15 mW per node
PLANAR RELIABILITY FanOut « 5° over tomo. range of —55° C. Fairchild Micrologic elements have been life tested for 1,000,000 Voltage -« mel + 30%
element operating hours at 125°C without a single electrical Package * 8 lead TO-5 type (.170 height) failure. The Fairchild Planar process provides total protection *The buffer element has a fan out of 25 with its integral oxide surface.
pul and wLogic are trademarks of Fairchild Semiconductor, a Division of Fairchild Camera and Instrument Corporation
10 CIRCLE 10 ON READER SERVICE CARD electronics
KLECTRONICS NEWSLETTER
Thermionic Solar Power System Passes Test
>
FEASIBILITY tests of a full-scale solar thermionic power system indicate such systems have a potentional energy conversion effi- ciency of 15 to 20 percent, General Electric reported last week. Future system for space applications may produce 10 w/b.
However, efficiency obtained in the initial test was low: 12.18 w were produced, using 195 sq ft of petal-shaped aluminum honeycomb collectors and 105 vacuum thermi- onic converters. Average converter temperatures during the test were about 250 C below the optimum of 1,150 C. GE says the converters are capable of 1.5 watts at 2.65 percent efficiency.
More efficient cesium vapor con- verters have been developed and advanced vapor types could be 25 percent efficient. One purpose of the tests, performed under a $300,- 000 Air Force contract, is to indi- cate design improvements.
The system includes switching to apportion output between battery and load during light and dark pe- riods, a regulator to maintain out- put at 26 to 29 v, a 23-cell nickel- cadmium battery and solar orienta- tion sensors. The latter adjust pedestal through servo controls.
Nuclear Generator Runs Buoy, Weather Stations
SNAP-7A NUCLEAR power generator is being tested by AEC and Coast Guard as a power source for ocean navigation buoys. Similar gener- ators are now being used at auto- matic weather stations in the Arctic and Antarctic.
The buoy power supply, made by Martin Marietta, consists of stron- tium-90 pellets whose radioactive decay heat is converted to electric- ity by 60 thermocouples. Output of 10 w at 5 v d-c is converted to 32 v d-c to trickle charge nickel-cadmium batteries. Life expectancy of the power system is 10 years. Regular buoy batteries must be recharged every year or so.
Also this month, the Navy de- livered to its base at McMurdo Sound the Antarctic’s first nuclear
December 29, 1961
power plant. Martin prefabricated the 1,500-Kw plant. Instrumenta- tion was supplied by Tracerlab.
First of New Satellite Tracking Stations Built
NASA REPORTS it is testing the key station in its new network to track and receive data from satellites. The $5 million station, near Fair- banks, Alaska, has an 85-foot dish antenna and enough automatic equipment to keep operating crews small.
The program calls for a second station at Rosman, N. C., and others in the Far East, Newfoundland and possibly elsewhere. The stations will record data from orbiting as- tronomical and geophysical observa-
Ben Franklin—1962
NEXT SUMMER, the bronze-hulled school Azara will be sailing around the Caribbean, trying to get hit by lightning.
Originally outfitted as a gen- erator of artificial atmospherics, the Azara is used for research in vif propagation and the poten- tial uses of both natural and man-made sferics for navigation and long-range communications (ELECTRONICS, p 53, July 22, 1960).
New program, directed by E. A. Lewis, of Air Force Cam- bridge Research Lab, will seek to intercept lightning bolts, some of which generate a terawatt of power for about 100 usec. Bolts will be triggered by shooting wires into clouds with rockets.
tories. The first OGO, scheduled for 1963, is to contain 19 experi- ments.
NASA is building another 85- footer near Fairbanks to receive data from future Nimbus weather satellites.
FCC May Give Community Tv Grants a Back Seat
WASHINGTON—FCC has tentatively decided that if a proposed com- munity antenna tv service threatens an existing tv station, the tv sta- tion will be protected. The commis- sion has directed its staff to write a decision denying a microwave grant to Carter Mountain Trans- mission Corp., which is seeking per- mission to provide service to three Wyoming communities. If FCC adopts the decision, it will report- edly be the first time it has denied such a grant to protect a going tv station.
Pistol-Packaged Laser Offered to Researchers
PORTABLE laser was commercially introduced last week by Kollsman Instrument for research and dem- onstration applications in such fields as optical communications, crystallography and medicine. The 9-in.-long ruby laser head is packaged like a pistol with double trigger grips. Power supply, oper- ating from battery or line vower, is in a case occupying less than a cubic foot. Laser threshold pump power is 90 joules, coherent light output wavelength is 6,943 A and light pulse train duration is 0.2 msec.
Looks Like West Ford Package Is Space Junk
INTENSIVE RADAR search for Project West Ford dipolés has yielded addi- tional returns indicating that the orbiting package has broken up into several pieces. Several small ob- jects in the right orbital plane ap- pear at times close to the calculated schedule.
The returns were picked up by MIT Lincoln Laboratory’s Millstone
1
Hill radar, not the West Ford radar, indicating the binder still hasn’t released the dipoles. Chances are the fragments will wind up as space junk.
Neither Lincoln Lab nor Air Force will say if there are plans to try again. Unofficial sources point out that the first launch was made only after presidential ap- ’ proval and that a second try is not likely until it is determined what went wrong.
Airborne Computer Scans Jet Engine Performance
COMPLEXITY of jet aircraft panels is reduced by a digital computer- scanning system announced last week by Bendix. In the Air Force’s four-engine test plane, 10 indicators monitor 80 engine performance conditions.
The system automatically calcu- lates which engine is operating at its most critical value for a flight situation. This engine’s conditions are displayed on vertical scales with movable indices indicating maxi- mum efficiency values.
If an engine function exceeds a critical value, the crew is alerted to the engine number. The crew can check any engine at any time by using selector switches.
Time Moves Faster, NBS Changes Frequency
IRREGULAR rotational speed of the earth—it’s getting faster—has prompted National Bureau of Standards and U. S. Naval Observa- tory to change the standard fre- quency and time broadcasts.
At zero hours GMT,. Jan. 1 (7 pm EST, Dec. 31), standard fre- quencies transmitted by NBS sta- tions (ELECTRONICS BUYERS GUIDE, p R47, July 20) will be made higher by two parts per billion.
Time pulses in 1962 will be off-
set from atomic time to correspond with time based on earth rotation. In 1962, frequencies will be 13 parts per billion lower than the cesium atom clock, whose frequency is 9.192631770 Gc. Changes will
12
also be made by Coast Guard’s east coast Loran-C stations.
Microwave Tube Center Is Slated for Midwest
CHICAGO—Hallicrafters and Com- pagnie Generale de Telegraphie sans Fil (CSF), of France, will set up a firm to produce high-power microwave tubes. The new com- pany will be called Warnecke Elec- tron Tubes, after the director of CSF’s tube division. Ground for a 17,000 sq-ft plant will be broken in February at one of three loca- tions now under consideration in the Chicago suburbs.
Robert F. Halligan, Hallicrafters president, said at a meeting of com- pany stockholders last week that it will have complete facilities for microwave tube R&D and produc- tion. Hallicrafters, which is invest- ing some $250,000, will have a 42 percent interest, CSF the rest. Maurice Ponte, of CSF, will be chairman of the new firm.
Seattle Schools Plan F-M Emergency System
SEATTLE—School board plans to in- stall an f-m emergency signal radio system in 119 school buildings. The installation, subject to FCC ap- proval, is primarily a civil defense safety measure, but will also give the schools what amounts to a closed-circuit communications sys- tem. Additional expense will be $28,800 for receivers plus $60 for each installation.
Four Subcontractors Named for Apollo
NORTH AMERICAN AVIATION last week named four subcontractors for the command module of NASA Apollo spacecraft. Collins Radio will receive more than $40 million for telecommunications; Minneapolis- Honeywell Regulator, $30 million, stabilization and controls; AirRe- search, $10 million, environmental control, and Radioplane, $1 million, recovery system.
in ‘Breee:.... 5
MAGNETIC Recording Industry As- sociation members expect sales gains of 12 to 15 percent in f-m stereo and 20 to 50 percent in tape. Tenney Engineering esti- mates environmental test and equipment volume in 1961 was $225 million, up $75 million.
SIMULTANEOUS control of as many as 20 satellites will be studied by Planning Research Corp. under Lockheed contract.
BURROUGHS is setting up its own finance corporation to expedite computer sales and leasing.
TRAINING simulator contracts in- clude $2.2 million to Curtiss Wright and $668,000 to Link, from Navy. Link will also build four fighter pilot trainers for Japan, which is getting 200 F104J’s.
GROUND DATA handling subsystem of the AN/USD-7 Air Force re- connaissance system will be made by Airborne Instruments Lab under $4 million contract. The $40 million system is being de- signed and produced by AIL, General Telephone, Sperry Rand, Raytheon and Filtron.
OTHER AIR FORCE awards include $7.5 million to Adler Electronics for long range, transportable communications systems; $2 mil- lion to AC Spark Plug for stellar inertial guidance R&D; $1.6 mil- lion to CompuDyne for analog- digital engine test stands; $1.8 million to Raytheon for radar countermeasures.
NAVAL equipment contracts include $300,000 to Transonic for sono- buoy transducers; $195,000 to Packard Bell for a digital svs- tem; $140,000 to Nytronics for airborne decoders.
ARMY orders include $922,000 to Taffet Electronics for field com- munications components; $250,- 000 to Craig Systems for com- munications shelters; $105,000 to Datex Corp. for an automatic meteorological data acquisition system.
MOTOROLA will build a 500-mile microwave relay for Santa Fe Railway; Philco, a 250-mile net from Voice of America studios in Washington to the 4.8-Mw transmitter at Greenville, N. C.
electronics
Model 187B-SL
COMPLETE LIN OF VERSATILE,
Model 187B-XB 13%”
for SL, S, C, XB and X Frequency Bands x grea i)
Model 187B-X ”
Five models covering five bands These Sierra high-power waveguide terminations are extremely
useful as dummy loads in calorimetric power-measuring systems. They feature rugged construction, with rigid plastic water tube mounted in waveguide section, diagonally oriented for impedance matching. Chokes and shielding minimize rf leakage, and a heater element built into each model permits rapid, accurate calibration of a calorimetric power-measurement system
against a low-frequency standard,
Three models useful iri pressurized systems VSWR less than 1.10
High average, peak power ratings
Low rf radiation
Calibration heaters in all models
Model Number:
Frequency Range: VSWR:
Power Average:
Peak Power: (Unpressurized) Max. Air Pressure: Waveguide:
Connector:
Recommended Water Flow: Pressure Drop at Rated Flow: Max. Water Pressure:
Water Temperature:
Water Capacity:
Water Renewal at Rated Flow: Heater Resistance:
Heater Rating:
Length:
Price: *Not pressurized
187B-SL
1.7 to 2.6 kme < 1.10 to 2.4 kmc < 1.15 to 2.6 kme
20 kw
2 megawatts * RG-105/U UG-437A/U 2 gpm for 10 kw 10 psi 80 psig 0 to 70°C 18.5 cu. in. Once per 2.5 sec, 4.5 ohms 10 kw at 2 gpm 50 in. $600.00
1878-S
2.6 to 4.0 kmc less than 1.10
10 kw 1 megawatt
RG-75/U UG-584/U 2 gpm for 10 kw 10 psi 80 psig 0 to 70°C 3.5 cu. in. 2 times per sec, 9 ohms 5 kw atl gpm 32 in. $500.00
Data and prices subject to change without notice. Prices f.0.b. factory
187B-C
§.8 to 8.2 kmc less than 1.10
5 kw
500 kw 45 psig RG-50/U UG-344/U 1 gpm for 5 kw 10 psi 80 psig 0 to 70° C 0.85 cu. in.
4.3 times per sec.
14 ohms 3 kw at 1 gpm 20 in. $425.00
187B-XB
7.0 to 10.0 kmc less than 1.10
3 kw
250 kw 45 psig RG-51/U UG-51/U 0.6 gpm for 3 kw 10 psi 80 psig 0 to 70° C 0.42 cu. in.
5.3 times per sec,
20 ohms
1 kw at 0.6 gpm 17.25 in. $400.00
187B-X
8.2 to 12.4 kmc jess than 1.10
2kw
150 kw 45 psig RG-52/U UG-39/U 0.4 gpm for 2 kw 10 psi 80 psig Oto 70°C 0.20 cu. in. 7.4 times per sec. 20 ohms 1 kw at 0.4 gpm 13.5 in. $375.00
For complete details, see your Sierra Representative or write direct.
Sierra also offers its Model 186 Series Coaxial Water Loads, covering dc to 4 kme.
SI@rra SIERRA ELECTRONIC CORPORATION
A Division of Philco Corporation 6807A BOHANNON DRIVE . DAvenport 6-2060 . MENLO PARK, CALIFORNIA, U.S.A, Sales representatives in all principal areas Canada: Atlas Instrument Corporation, Ltd., Montreal, Ottawa, Toronto, Vancouver Export: Frazar & Hansen, Ltd., San Francisco 6807
December 29, 1961 CIRCLE 13 ON READER SERVICE CARD 13
COAXIAL ca BL E-S
-».-FOAMED DIELECTRIC
Raychem Corporation's irradiated modified cellular polyolefin miniature coaxial cables fill a specific industry need. Small high temperature cables manufactured with conventional dielec- tric materials have solved many prob- lems of space and weight, but not without sacrificing certain important mechanical properties.
A series of cables utilizing high strength, solderable, irradiated cellu- lar polyolefins have been created. For a specific impedance they are dimen- sionally equivalent to standard poly- tetraflouroethylene dielectric miniature RG series cables.
The unique foam, with its low dielec- tric constant of 1.5, permits a radical increase in center conductor size. This results in elimination of the widespread problem of center conductor breakage while significantly lowering both ca- pacitance and attenuation. Coincident weight reductions of up to 50% are also achieved.
leader in radiation chemistry
®
RAYCHEM
CORPORATION
OCAKSIOE AT NORTHSIOE REOWOOD CITY. CALIFORNIA
CIRCLE 14 ON READER SERVICE CARD
WASHINGTON OUTLOOK
MINUTEMAN PRODUCTION will be in- creased as a result of the Pentagon’s deci- sion to scrap the mobile version and concen- trate on fixed-base deployment. Funds initially earmarked for the mobile system will now be spent on additional underground launching silos. Concern over guidance was a factor in the decision, but the overriding reason was cost. The railcar version costs close to 50 percent more than the fixed-base missile.
NAVY will use its own advanced fire control system in the carrier-based version of the TFX tactical fighter plane which it and Air Force are developing jointly. Navy’s fire control system will presumably be optimized for air-to-air operations, as distinguished from the Air Force’s emphasis on air-to- ground combat. Navy’s Bureau of Weapons plans to award an R&D contract shortly for the new system.
Similarly, Air Force plans to award the prime contract on TFX within the next couple of months. TFX is planned as a suc- cessor to the Air Force’s Republic F-105 and the Navy’s McDonnell F4H. Initial operation is scheduled for about 1966. Mean- while, the Air Force plans to buy F4H air- craft next year and reduce scheduled pro- duction of the older F-105.
UPCOMING CONSOLIDATION of military supply management of electronic parts will cover 450,000 different common-use Penta- gon catalog items, including a considerable quantity of electrical components. The items represent a military inventory worth $600 million with annual purchases now averaging $150 million. No decision has been reached on when the consolidation will be made.
CENSUS BUREAU has started issuing its detailed statistics from the 1960 census on the use of appliances, tv and radio sets in U.S. homes. Brief advance summaries have been issued for a number of states. Both advance reports, and the vastly more detailed final reports, have been issued for Utah and Vermont. The rest can be obtained as they are issued, between now and May 1, from the Bureau.
Validity of comparisons between the 1960 and 1950 census figures has been questioned because of changes in reporting methods. For example, in 1950 census takers asked the questions, but last year, those selected for detailed queries filled out the forms themselves. In addition, the definition of “household” was broadened in 1960. In some cases, the number of homes having a particular appliance increased, but the saturation per- centage declined.
electronics
FOR THE MISSILE
December 29, 1961
RAYCHEM WIRE AND
COAXIAL .
CABLES
AND SPACE AGE
CORPORATION
4 RAYCHEM ®
CIRCLE 15 ON READER SERVICE CARD
15
| % | | a a .
AND PRECISION FORK 1 TO 40,000 CYCLES
i : | i ll
TYPE 2007-6 FREQUENCY STANDARD
Transistorized, Silicon type Size, 1%" dia., x 342” H., Wt., 7 oz. Frequencies: 360 to 1000 cy. Accuracies: 2007-6 + 0.2% (—50° to +85°C)
This frequency standard (360 R2007-6 + .002% (+15° to +35°C)
W2007-6 + .005% (—65° to +85°C) Input: 10 to 30V DC at 6 ma. Output: Multitap, 75 to 100,000 ohms
TYPE 10
145° x! en
or 400 cycles) is accurate to + 50 parts per million at 10° to 35°C. Aging has been greatly minimized. TYPE 2001-2 FREQUENCY STANDARD Size, 334” x 442" x 6” H., Wt., 26 oz. Frequencies: 200 to 3000 cycles Accuracy: +.001% at +20° to +30°C Output: 5V at 250,000 ohms TYPE 2007-6 P , Input: Heater voltage, 6.3 - 12 - 28 B voltage, 100 to 300 V, at 5 to 10 ma. TYPE 25 > : Accessory Modular units are available to TYPE 2001-2 divide, multiply, amplify and power this - unit.
External power of 1.4 volts at 6 mitroamperes powers the unit.
TYPE K-5A FREQUENCY STANDARD
Size, 342” x 3” x 1%"
Weight, 11 lbs.
Frequency: 400 cycles
Accuracy: .03%, —55° to +71°C
Input: 28V DC +10%
Output: 400 cy. approx. sq. wave
at 115V into 4000 ohm load (approx. 4W)
TYPE 25 PRECISION FORK
Size, 56” dia. x 2%"
Weight: 2 ounces
INQUIRIES INVITED Frequencies: 200 to 1000 cy.
Accuracies:
For over 20 years we have made fre- R-25T and R-25V + .002% (15° to 35°C) quency standards and precision tork 25T and 25V + .02% (—65° to 85°C)
units for applications where consistent For use with tubes or transistors accuracy and rugged dependability are ;
vital. Shown ore just a few typical examples.
Some users integrate our products with
instruments of their own manufacture. In
other cases we develop complete assem- & M E R I C a N T I M E P R O D U C T S blies to meet special needs. DIV. OF BULOVA WATCH COMPANY, INC.
You are invited to submit any problems 61-20 Woodside Ave., Woodside 77, L. I., N.Y
within the area of our activity for study
by our engineering staff. WESTERN OFFICE, 234 N. LAKE AVE., PASADENA. CALIF
16 CIRCLE 16 ON READER SERVICE CARD
electronics
ESSING THE BEAM
WHAT IS E-BEAM EQUIPMENT? WHAT IT IS: Alloyd Electronics’ WHAT DOES IT DO? CAN IT BE PUT TO possible contamination free,
electron beam equipment con- sists of a line of completely self- contained units employing elect- ron bombardment heating, carried out in a vacuum, for evaporating, welding, brazing or zone refining.
MAJOR APPLICATIONS: Evaporation: Alloyd electron beam equipment can be used to produce high purity thin metallic and non- metallic films by vapor deposition of high temperature materials. Films can be made from the most difficult ma- terials, including beryllium, tantalum, silica, alumina. Useful thin-film applications: Electronics, where thin films can perform as capacitors, resistors, magnetic memory devices, etc. . . . optics, where thin films with unusual optical properties are being developed . countless other applications.
..and
WORK FOR YOU ECONOMICALLY?
narrow heat affected zone welds in titanium, beryllium, tungsten, molybdenum, etc.
MAJOR ADVANTAGES OF ALLOYD EQUIPMENT: 1. Modular design, for flexibility: basic components of any Alloyd system, including electron gun and power supply, vacuum chamber, and vacuum pumping system are available in practically unlimited combinations for maximum flexibility, and can be easily and economically tailored to any application. 2. Voltage is low and safe (30,000 volts max.) eliminating x-ray hazards to the op- erator. 3. Maintenance is simplified. For example, the electron gun filament in any Alloyd unit can be serviced without removing the gun. 4. Operation is simplified. Fingertip controls, located directly underneath the cham- ber, make for maximum operating ease and efficiency.
Benefits to be derived from Alloyd’s look-ahead modu- lar design are both numerous and substantial, not only in terms of reliability, but in terms of flexibility and cost.
It will be well worth your while to write today for com- plete information.
Welding: Alloyd Electron Beam Welders (see below) are designed for experimental or production welding and brazing of refractory and reactive metals. High vac- uum is coupled with high power density — makes
alloyd electronics corporation WF 35 Cambridge Parkway, Cambridge 42, Massachusetts
4 Mark Vi Electron Beam Welder — for clean, crack-free welds in even the most refractory and reactive metals by electron bombard- ment. High vacuum eliminates contamination. Ultra-narrow heating zone permits optimum control and precision in handling very thin pieces or welding thin-to-thick sections.
Mark V Electron Beam Evaporator— a reasonably priced, highly flexible unit for producing thin metallic and non-metallic films by vapor deposition through electron bombardment heating. Completely self-contained. An invaluable research and development tool for thin- film applications, including micro-miniaturized electronic circuitry, optical filters, resistors, capacitors, memory devices, countless other components.
The Electron Beam at your service — Our laboratory is part of an advanced, complete facility for electron beam welding, brazing, evaporating, melting and zone refining maintained by Alloyd to meet custom requirements. We also offer engineering, consulting and R&D services in systems design and development. Ask us for complete information.
5 l=Y=) EYE
CIRCLE 17 ON READER SERVICE CARD CIRCLE 18 ON READER SERVICE CARD->
Almost all security minded nations depend on
ePEARY
4 HS Som de), Iie TUBE DIVISION
systems using Sperry electronic tubes
SPERRY RAND CORPORATION GAINESVILLE, FLA. GREAT NECK, N. Y.
With Wrap” tools
these hands wrap up wiring jobs fast
Keep expensive hands working at top efficiency and ingly secure, conquer vibration failure and corrosion. get permanent, solderless electrical connections in a And only Gardner-Denver offers a complete line of hurry with Gardner-Denver “‘Wire-Wrap”’ tools. equipment for making such connections— including
Proved superior by leaders in communications and custom-designed, automatic machines to expedite electronics, solderless wrapped connections are last- multiple operations.
Air-powered Electric-powered Manual wrapping and Hand-Squeeze “Wire-Wrap” tool. “Wire-Wrap” tool. unwrapping tools. “Wire-Wrap” tool.
EQUIPMENT TODAY FOR THE CHALLENGE OF TOMORROW
GARDNER - DENVER
Gardner-Denver Company, Quincy, IIlinois—Offices in principal U.S., Canadian and Mexican cities in Canada: Gardner-Denver Company (Canaca), Ltd., 14 Curity Ave., Toronto 16, Ontario international: Gardner-Denver International Division, 233 Broadway, New York 7, N. Y
Internationa! Offices: Buenos Aires. Argentina; Artarmor, N.S W. Australia: Brussels, Beirium. Rio de Janeiro, Brazi Santiago, Chile: Barranquilla, Colombia; Lima, Peru; Ndola, N. Rhodesia, Salsbury, S. Rhodesia, Johannesburg Transvaa
20 CIRCLE 20 ON READER SERVICE CARD electronics
1 Microsecond
Now available from Daystrom as standard units, these 1 »sec modularized core memories permit manufacturers of digital machines to eliminate expensive component development. The modules offer design flexibility never before available to computer engineers. Full read-write cycle time for the modules is 1 psec or less, and access time is typically 0.5 psec. The standard memory has a capacity of 1024 words, 50 bits to the word, and can be expanded in multiples of this capacity up to 4096 words and 200 bits per word. Components are stacked to give high package density. Only two different voltages ...+20V and —20V... are required, and the full driv- ing current is only 360ma. All solid-state and highly reliable, the standardized modules reflect Daystrom Military Electronics Di- vision’s extensive experience with MIL memories and circuitry such as the NORC and 465L systems. Send for technical data.
| DaAYstRom , INCORPORATED Lv
MILITARY ELECTRONICS DIVISION
ARCHBALD, PENNSYLVANIA «+ JERMYN 876-1500
December 29, 1961 CIRCLE 21 ON READER SERVICE CARD 21
#
7
An unusual combination of advantages found only in mercury-wetted relays has led many design engi- neers to specify them for tough switching jobs. Here are but 3 typical characteristics of our JM series:
RELIABILITY. Sealed-in-glass mercury contacts are renewed with every operation. Won't pit or weld. Make or break is positive . . .every time. No bounce, no chatter. Signals ranging from a few micro amps to 5 amps are switched with singular consistency.
LONG LIFE. Think in terms of billions of operations when considering JM series relays. Proper applica- tion, of course, is a requisite.
SPEED. Operate time is just less than 3 milliseconds using 2 watts of power. Release time is about 3.2 milliseconds. Thus, relays can be driven 100 times per second.
If your project calls for exceptional relay perform- ance, perhaps the answer lies in our JM Mercury- Wetted contact relay.
DIVISION OF AMERICAN MACHINE & FOUNDRY COMPANY .
IN CANADA:
¢
sorree & GRY
IF YOUR RELAYS MUST
SWITCH UP TO 100 TIMES
PER SECOND
HAVE A LIFE
IN EXCESS OF
A BILLION CYCLES
BE COMPLETELY RELIABLE
AND FREE FROM CONTACT BOUNCE
THEN SPECIFY
P.B
MERCURY WETTED
CONTACT RELAYS
| ontact Relays?
JM SERIES ENGINEERING DATA
Contact Rating: 5 amperes maximum 500 volt maximum 250 volt-amp max. with required contact protection.
Contact Configuration: Each capsule SPDT. Combination of capsules in one enclosure can form DPDT, 3PDT, 4PDT. (All Form D.)
Terminals: Plug-in or hook solder; 8, 11, 14, or 20-pin headers.
More information? | :
Write today for free catalogue. _
Coil Resistance: 2 to 58,000 ohms.
P&B STANDARD RELAYS ARE AVAILABLE AT YOUR LOCAL ELECTRONIC PARTS DISTRIBUTOR
POTTER & BRUMFIELD
PRINCETON, INDIANA
POTTER & BRUMFIELD, DIVISION OF AMF CANADA LIMITED, GUELPH, ONTARIO
PSI ... Lhe industry’s Number One supplier
of Silicon Welded Assemblies now announces
MICRO LOGIC MODULES
Circuits at prices as small as their size
Dual Emitter Follower Dual Inverter
|Flip Flop [eal
Psi9i3 4
“And” Gate “Or” Gate
all operating at two megacycles
Here is the logical answer to the logic circuit designer seeking micro-size units for the microminiaturization program he needs to put into effect now!
Delivery is good ... prices are surprisingly low... performance and reliability are tops! These new 2mc Micro Logic Modules will measure up to your most exacting standards of reliability because PSI Micro- Diodes and Micro-Transistors are used in every unit.
All-welded assembly and epoxy encapsulation assures high resistance to shock and vibration . . . excellent moisture integrity. The Micro Follower, Inverter and Flip Flop are %” cubes; the gates only 7/16”. Terminals are on .1” grid spacing.
For detailed specifications, prices and delivery sched- ules call any PSI Field Engineering office. See your Yellow Pages.
A Pacific Semiconductors, Inc
AN A SUBSIDIARY OF THOMPSON RAMO WOOLDRIDGE INC.
12955 Chadron Ave., Hawthorne, California e« Cable: PSISOCAL TWX: HAW CAL 4270 OR 8-4711, OS 9-2281
~<—CIRCLE 22 ON READER SERVICE CARD
CIRCLE 23 ON READER SERVICE CARD 23
+ '
[ |
(Actual Size)
Alternate Action Lighted Pushbutton
In one cubic inch: double-pole double- throw switching; split-color screen (your choice of 15 color combinations); two lamps under screen. Also available in same size: momentary action switch, and indicator unit without switching function. Write for Data Sheet 182:
MICRO SWITCH ... FREEPORT, ILLINOIS A division of Honeywell In Canada: Honeywell Controls, Limited, Toronto 17, Ontario
Honeywell MICRO SWITCH Precision Switches
electronics
nae
MICRO SWITCH
HAS MORE ANSWERS FOR CUSTOMIZING
YOUR CONTROL PANELS!
‘i i Modular earicts
795 Rocker “6 AT" “13 AT” toggle “17 AS” rotary “2 PB” push-button “Series 2”
actuator switch t | itch ith indi lecto itch itch a mobi “50 PB” lighted ctu r swi oggie switc with tabindicator select r swite switch assembly push-button assembly
MORE SWITCH DESIGNS, MORE FLEXIBILITY IN THE MICRO SWITCH PUSH-BUTTON LINES
When you want a control panel precisely tailored to your equipment and absolutely reliable, start with MICRO SWITCH. You'll find the wider selec- tion fits your ideas, rather than your ideas having to fit the selection.
New “302 PB” Miniaturized Lighted Push- Button Switches provide infinite lamp life, double-pole double-throw switching and 2-color indication in a unit requiring only one cubic inch of panel space.
Modular “Series 2” Lighted Push-Button Switches offer customized combinations of eight
different basic switches and dozens of colored indicators—and they snap together without tools. New truncated display screens add dimensional visibility.
MICRO SWITCH also makes the “Series 50 PB” lighted push-button switches as well as hundreds of different toggle switches and assemblies. Everything you need for customizing control pan- els. See the Yellow Pages for the nearby MICRO SWITCH Branch Office. Write for illustrated cata- logs on push-button and toggle switches for con- trol panels and machine control stations.
December 29, 1961 CIRCLE 25 ON READER SERVICE CARD 25
MICROWAVE RADIOMETER
The measurement of this noise radiated by all objects according to their temperature and surface characteristics makes possible:
Detection of distant invisible radio stars tric Amplifier with regulated Location of icebergs through clouds from high flying aircraft
pply developed for use in
D me range Mapping of the surface of the sun
All-weather celestial navigation
Detection of objects under the ground or snow Mapping of the earth’s surface from moving aircraft
MELABS has been a pioneering leader in this relatively new field. Its activities have ranged from theoretical studies to development and manufacture of a wide range of radiometer systems and components.
SYSTEMS: RMR-1 35 Gc Radiometer System (illustrated to the left Ferrite SPDT Switches—electronically switched at 100-1000 cps for above) features 0.5°K sensitivity and 0.8° antenna resolution. Uses switching between antennas and reference loads. Available from 1 ke ferrite reference switch. Reference is adjustable from 77 K 1 to 35 Gk
to 15,000°K
TWT Radiometers at 1400 and 3000 mc feature low noise TWT broad- band amplifiers
Solar Spectroheliograph—3000 mc radiometer for mapping TWT Preamplifiers—for broadband radiometers with noise figures of sun's surface. 5-10 db. Mounts on antenna
Ferrite Circulators and Isolators with ultra-low loss, (0.1 db typical for radiometer front ends
COMPONENTS: Parametric Preamplifiers—availabie from 700 mc to Masers—broadband traveling wave types for the ultimate in 6000 mc with broad bandwidths (20% or greater system sensitivity
Melabs invites your inquiries on Radiometer Systems and Components.
3300 HILLVIEW AVENUE /STANFORD INDUSTRIAL PARK/PALO ALTO. CALIFORNIA
TELEPHONE: DA 6-9500, AREA CODE: 415; TWX: PAL AL 138
Employment opportunities at Melabs are exceptional for ambitious engineers and physicists; write in confidence,
DEPT. B-7 AN EQUAL OPPORT
26 CIRCLE 26 ON READER SERVICE CARD
electronics
A basic formula from Information Theory ... provides a measure of the amount of information in a particular type of message, such as TV ... helps determine the frequency bandwidth, for example, required to transmit the messages. Information Theory, pioneered at Bell Laboratories, guides the search for better communications systems
DISCOVERY
AT BELL TELEPHONE LABORATORIES
New knowledge comes in many forms. Sometimes it comes in a mathematical formula. Usually it comes after much thought and experiment and the fruitful interaction of different minds and abilities. Most often, too, a particular discovery is small. But many small discoveries have a way of leading to big ad- vances at Bell Laboratories—advances like the transistor .. . or, more recently, the gaseous optical maser, forerunner of communications at optical frequencies. Opportunities for dis- covery are enhanced by the abilities of the scientists
and engineers and the range of the facilities at Bell
Laboratories, world center of communications re-
search and development.
Iterative Techniques Widen Applications ot
Small analog and digital computers at Eastern Joint Computer Conference
point up data processing trends. Input-output systems gain in speed
1
By WILLIAM E. BUSHOR,
Senior Associate Editor
WASHINGTON—-Iterative techniques —-opening the door to application of analog systems in statistical work— was one of the important trends evi- dent on the exhibit floor at the Eastern Joint Computer Confer- ence. While big computers were prominently showcased, it was the smaller computers—both analog and digital—which set the pace.
Shown was GPS _ Instruments’ iterative analog computer for simu- lating missile flight paths. High- speed predictions of impact point location can be determined from given missile data.
The computer, operating in a fast, repetitive mode, accepts flight data as its initial conditions. It com- putes the flight paths, evaluates how far the missile will miss the target and makes_ incremental changes in flight path parameters to minimize miss distance.
The new parameter values are fed back to the missile control system to correct the trajectory. New flight data is then used for another itera- tive solution series. In the photo, an engineer varies the controls to simulate changing flight data. Ef- fect on missile trajectory prediction is displayed by the cro and an x-y plotter.
The system gives 50 solutions a second. Because a time scale com- pression of 3,000 to 1 is used, wide- band components such as a d-c to 1-Mc operational amplifier and d-c to 40-Ke multiplier are needed.
GPS expects this approach can also be used to simulate sampled data systems and transport delays, and to evaluate double integrations using multiple time scale _ inte- grators.
Another new analog computer is
28
Electronic Associates’ solid-state Pace TR-48. This desk-size unit has enough capacity for complex re- search and engineering problems, particularly in the aerospace and process sciences, but does not need an air conditioned environment or special power supply. It can be placed on a cart and wheeled around labs or engineering areas.
While parts of the computer are operating at high repetitive speeds, the remaining circuits can work on other problem variables at slower repetitive rates or real time. Thus, it can handle certain classes of de- sign problems—such as multidi- mensional flow and heat transfer— ordinarily solved on larger com- puters, EIA says.
Among other small computers were Comcor’s analog system, Har-
EJCC SIDELIGHTS
Change was the byword for this, the 19th Joint Computer Confer- It had a new sponsor, the American Federation of Informa- tion Processing Societies. IFIPS does not plan to continue the re- gional format next year.
Attendance, more than 4,000 con- ferees and over 90 exhibits, was the largest yet. There were 29 papers —selected from a total of after 961 and 27 movies presented.
The theme was “Computers: Key to Total Systems Control.” The keynote speaker was D. L. Bibby, president of Remington Rand. He urged that the ratio of time spent in hardware’ development as against improving computer utili- zation, 1,000:1, be changed.
Computers, he feels, are not ex- ploited sufficiently for benefit to ness, manufacturing medicine,
ence.
242
manuscripts reviews—
now about
maximum national defense, busi- techniques, sciences and education.
vey-Wells Electronics’ general-pur- pose digital system and Control Data’s 160-A. The latter, a desk- sized digital computer, exchanges data with input-output devices at any rate up to 70,000 words a sec- ond. It buffers data while comput- ing or while the operator manually enters data.
Continuing problems of develop- ing peripheral equipment able to match computer speeds aroused the usual interest in input-output de- vices. This year, the emphasis cen- tered on recording equipment.
For example, General Dynamics/ Electronics’ S-C 4020 can operate on-line at most computer speeds or can work off-line from magnetic tape. It records characters at 21,000 a second and plots graphs at 12,500 points a second. Complex multiview engineering drawings, schematics, numerical tool paths or diagrams like the Pert network illustrated (ELECTRONICS, p 30, Nov. 17) can be made in a half second. Curves, tables, alphanumeric printing or a combination of these, derived from digitally-coded data, are displayed on a shaped beam tube. The image is split optically to fall on the lenses of microfilm and _ photorecording cameras, producing both films for storage and hard copy on paper.
A special projector allows conven- tional formats to be combined with the image, making preprinted forms unnecessary. An axis gener- ator draws horizontal and vertical graph axes starting at any point in the display area. A vector gener- ator draws straight lines between any two points.
Omnitronics’ Omni-Data ETR-7 gets around mechanical tape punch- ing by electrostatically producing black spots on tape in the same code configurations used on punched tape. The company says this meth-
electronics
Analog Systems
GPS analog system plots changing missile trajectory
od is reliable, long-lived and can be
used with high-speed digital com-
puters. Demonstrated with Omnitronics’
photoelectric tape reader, the sys-
tem recorded 400 characters a sec-
ond. Higher speeds and greater
packing densities are possible, it
was reported. FLIGHT Ampex introduced a random-ac- _ !NITIAL SILE PATH
Ae ape CONDITIONS sige AND
cess ferrite core memory which op- —(veLocity, \
erates at 1.5 usec for each complete Ho Saas OMPUTATION a
operating cycle (667 Kc). Each DATA
module of 32 planes can store 2,048
56-bit words. The module uses a
linear (word select) drive system f
and operates in the read-restore, System uses
. . : automatic
clear-write and split read-and-write praeeereatae
ee MISSILE PARAME TERS COMPUTA logic control Basic unit of the TM-4 tape mem- — CONTROL TIONAL
ory is a plastic strip with 30-mil- SYSTEM
thick ferrite cores mounted along
the edge. A read and write drive
line traverses all cores associated
with one word. Planes contain 35
strips. Sense-digit lines are
threaded through each core in a
plane associated with a specific dig-
ital position in a word. For preventive maintenance of
tape, General Kinetics showed a
cleaner which removes loose oxide,
tape base chips and dirt without af-
fecting stored data. It uses high-
energy sonic and ultrasonic cavita-
tion in a detergent solution directed
at tape edges and surface. Operator of EAI computer can use oscilloscope for readout of repetitive Other systems, previously an- operation
nounced but exhibited for the first
time, included Digitronics’ system
for transmitting tape or card in- :
put information over phone lines to Turns |
a central computer at 1,500 wpm. . ANN | 1% } AY National Cash Register operated \ , | A} their memory which uses cards car- : : i
rying seven magnetic tracks. The
memory has 16 cartridges, each con-
taining 256 cards, each of which
can store 21,700 characters. Any
ay a Pert network is formed on image tube of GD/E recorder (left). Basic card can be selected in 170 msec.
unit of Ampex memory is string of cores on plastic strip
December 29, 1961
ate ae
orbeamienclt
ant atelectasis Patt aEe ei
gamete
Pilot’s reactions to flight problems are shown on control console
Safety engineer sits at monitor console as gondola moves inside ball-shaped plastic “universe”
Gondola Makes Dry Runs in Space
DALLAS—Space flight simulator controlled by an analog-digital com- puter system is being used by Ling- Temco-Vought to duplicate realis- tically flights in manned orbiting, lunar and interplanetary vehicles. All phases of a mission, including launch, orbit, rendezvous, mid- course guidance, reentry and land- ing, can be performed. To heighten realism, a tv system shows the pilot the type of space scenes he would
see through a periscope. The pilot _
is also watched, on a tv monitor.
The pilot sits in a single-place gondola with a complete set of working controls and instruments. Movement of the gondola, instru- ment operation and a star field are controlled by the computers as the pilot is subjected to flight : situa- tions. The company plans to add noise and other factors contribut- ing to pilot sensations and instru- mentation to measure his physical reaction to flight stresses.
A general purpose analog com- puter with added analog-digital conversion and digital computation capabilities is used. The system in- cludes 800 operational amplifiers and potentiometers, 11 multipliers, 47 multiplying servos, 31 function generators, 13 six-channel record- ers and six course plotters. All the cockpit instruments are repeated on the control panel.
The flight simulator is part of a simulator center under develop-
30
ment. An automatic controls evalu- ation simulator is also in operation and an environment simulator for testing satellites, vehicles and sys- tems will be added soon.
The company recently installed a nuclear facility with a 3-Mev Van
de Graaf accelerator and a plasma arc machine. It is being used to in- vestigate radiation effects on mate- rials and equipment, to design plasma engines, to study the nu- clear-powered missile, Slam, and for other development work.
Engineer Supply Drops Sharply
SHORTAGE of engineering graduates during the next several years is pre- dicted by the Engineering Man- power Commission of Engineers Joint Council, New York. The short- age will come at a time when de- mand is rising sharply, EMC said, indicating a “crisis” may be near.
A survey of 186 colleges showed that freshmen engineering enroll- ments have dropped two to three percent this vear, continuing the trend for the fourth vear. Only the East South Central, Mountain and Pacific states showed an increase. Middle Atlantic enrollments dropped the most, 6.6 percent.
Engineering students represented 10.8 percent of all freshmen in 1957. This year, they are less than seven percent. In 1950 there were 52,700 graduating engineers; in 1960, 37,800. Present enrollment will yield about 32,000 in 1965.
EMC points out that this will not
supply half the average annual de- mand forecast by the National Science Foundation: 81,000 engi- neers a year during 1961-70.
Some of the drop may be reflected in increased science enrollments. Among 46 schools that supplied in- formation on both types of enroll- ments, science enrollments rose 24.4 percent, but engineering enroll- ments also rose 2.5 percent in these schools.
Computer Runs Parking Garage
NEW YORK—A fully automatic ele- vator garage opened here this month. One attendant-cashier sit- ting at a console selects a parking stall for a customer and collects the fee. The rest of the operation—
electronics
from parking and retrieving the car to computing the fee—is han- dled by a small computer and other controls.
Developed by Speed Park, Inc., and Otis Elevator Co., the garage on West 43rd St. has two elevator towers, each servicing two parallel sections nine stalls long and eight stalls high. Some 27 cars can be parked in 10 minutes.
The motorist drives his car onto one of two parking stations and leaves it. A barrier is raised around the car. The attendant selects a key numbered and cut to designate the stall. The key is inserted in a key- hole. Photoelectric cells sense the stall location from the key shape. The key is given the motorist as his claim check, along with a printed record of stall number and time.
The car is lifted in the station on parallel ribs. Steel fingers on an ele- vator draw the car into the ele- vator. The elevator delivers the car to the stall. The operation is re- versed when the motorist returns with the key. The parking fee is displayed on a screen and time and fee are printed on a receipt.
The parking computer is based on standard digital logic modules made by Digitronics Corp. It has a magnetic memory of some 8,100 cores, 30 for each stall. They store information on whether a stall is occupied, parking time and date.
Key inserted in control board selects parking stall
Car is lifted from parking station by fingers of elevator
CIRCLE 31 ON READER SERVICE CARD—>
PS-207 7-channel recorder used in Trieste bathyscaph
THINK DEEP
You're looking at the natural habitat of the Pl tape recorder. Beneath the surface, you'll find Pl tape machines at work in conventional and nuclear submarines, in exploration of the ocean floor, in ASW sounding and detection buoys, and in oceanographic research. You'll find them wherever there’s an exceptional premium on reliability — cruising under the polar ice cap, probing the darkest depths aboard the Trieste bathyscaph, handling important Polaris telemetry and computer assignments.
You needn't go very deep to discover why Pl recorders need very little of man’s most valuable undersea commodity — space. They pack far more performance into far less space than conventional recorders, require less power, generate less heat, need less mainte- nance. Their rugged, light-weight, all-solid-state design offers simpler installation, easier mobility.
Pl recorders aren't all beneath the surface. They're veterans of orbital satellite flight, and are familiar equipment in hundreds of laboratory, scientific, and industrial applications. They’re made in numerous configurations, for analog or digital recording on 1 to 16 or more tracks, in standard speed ranges push-button controlled from 15/16 to 60 ips, with frequency response from 0 to over 200 kc.
Whether your recording applications are under the sea or above it, we'd like to demon- strate Pl’s approach-in-depth. And whether you are presently using strip charts, punched tape, or pad and pencil to gather data, you may find that upgrading to magnetic tape not only provides increased flexibility and reliability, it may also more than pay for itself through savings in time and money. Ask your PI representative for our current brochure, or write direct.
1011 Commercial Street * San Carlos «+ California Phone LyYtell 11-4441 . Representatives in principal cities throughout the world
TWX: SCAR BEL 3O
(J) PRECISION INSTRUMENT COMPANY
Pl invites inquiries from design, application, and sales engineers.
Ar.
"MODEL 500 "INTERFERENCE LOCATOR
a me tm te hr
This versatile instrument is a highly sensitive interference lo- cator—with the widest frequency range of any standard available unit! Model 500 tunes across the entire standard and FM broad- cast, shortwave, and VHF-TV spectrums from 550 kc. to 220 me, in 6 bands.
It’s a compact, portable, rug- ged, versatile instrument—engi- neered and designed for most efficient operation in practical field use. It features a transistor- ized power supply, meter indi- cations proportional to carrier streagth as well as sensitivity of 5 microvolts minimum for 5% meter deflection over entire tun- ing range.
For full details, send for bro- chure IL-106,
SPRAGUE ELECTRIC COMPANY
35 Marshall Street, North Adoms, Mass.
SPRAGUE
32
THE MARK OF RELIABILITY
CIRCLE 32 ON READER SERVICE CARD
Members of the Project Oscar Association with their satellite
Hams Orbit Their Own Satellite
AMATEUR RADIO operators officially got into the space business shortly before noon on Dec. 12 when Oscar (Orbiting Satellite Carrying Ama- teur Radio), a ten-pound transmit- ter, piggy-backed into space from Vandenberg Air Force Base on Dis- coverer 36.
Oscar separated shortly after- wards to establish its own orbit. Initial radio pick-up was made by KC4USB, Marie Byrdland, at 1:08 PST as the satellite made its first pass over the South Pole.
Continuing around the world, the orbit’s second fix was established at Kodiak, Alaska by KL7EDM at 2:08 PST. Subsequently, it heard in the Hawaiian Islands and again at the South Pole, establish- ing that it was in its expected orbit.
Project Oscar, conceived and exe- cuted by a group of radio amateurs in the San Francisco Bay area, ulti- mately aims at providing the world’s hams with an international satellite communications system to back up conventional communica- tions in time of emergency. First satellite of the program is merely a transmitter which beams out the word HI at approximately 10 times a minute. The group hopes to build relay capabilities in future satel- lites.
Oscar operates on a band of two meters at a frequency of 145 Mc, and puts out a 100 milliwatt beacon signal. Expected life was three weeks to one month. Hams with sensitive receivers and high gain antennas should be able to pick up the signal as far away as one thou-
Was
sand miles. The American Radio Relay League estimates that many of the world’s 300,000 radio ama- teurs are participating in tracking.
The satellite uses transistor oscil- lator, power amplifiers and keyer. The rate at which it sends its signal is governed by a thermistor. Out- side measurements of the satellite are one ft square by six in. deep. The mechanism which ejected the satellite from its parent satellite automatically turned on the trans- mitter and erected the antenna.
Project Oscar was originated in 1959 by Donald Stoner, Alta Loma, Calif. He was joined in the effort by several engineers from various California space and missile com- panies. Director of field operations for the project is Fred Hicks. Both are employed by Lockheed Missile and Space Division in Sunnyvale, Calif.
All work on Oscar has been per- formed by the group during off- duty hours and funds for the effort have been privately raised.
Satellite is a foot square and a half-foot deep
electronics
MEETINGS AHEAD
RELIABILITY AND QUALITY CONTROL Symposium, PGRQC of IRE, AIEE, ASQC, EIA; aa Hilton Hotel, Washington, D.C., Jan. 9-11, 1962.
OPTICAL CHARACTER RECOGNITION Sym- posium, Nat. Bur. Stds.; Dept. of Int. Aud., Wash., D.C., Jan. 15-17, 1962.
ELECTRICAL ENGINEERING for electrical-electronics AIEE; N.Y. 29-Feb. 2,
Exposition
industry, Coliseum, N.Y.C., Jan. 1962.
REDUNDANCY TECHNIQUES FOR COMPUT- ING SYSTEMS, Office of Naval Re- search; Dept. of Interior Aud., Wash- ington, D.C., Feb. 6-7, 1962.
MILITARY ELECTRONICS Convention PGMIL of IRE; Ambassador Hotel, Los Angeles, Feb. 7-9, 1962.
SOLID STATE CIRCUITS, Internat. Conf., PGCT of IRE, AIEE; Sheraton Hotel and U. of Penn., Philadelphia, Pa., Feb. 14-16, 1962.
APPLICATION OF SWITCHING THEORY TO SPACE TECHNOLOGY Symp., USAF, Lockheed Missiles & Space; at Lock- heed, Sunnyvale, Calif., Feb. 27-Mar. 1, 1962.
SCINTILLATION AND SEMICONDUCTOR Counter Symp, PGNS of IRE, AIEE, AEC, NBS; Shoreham Hotel, Wash- ington, D.C., Mar. 1-3, 1962.
MISSILES & ROCKET TESTING Sympo- sium, Armed Forces Communications & Electronics Association; Coca Beach, Fla., Mar. 6-8, 1962.
EXTRA-HIGH VOLTAGE COMMUNICATION, CONTROL & RELAYING, AIEE; Baker Hotel, Dallas, Tex., Mar. 14-16.
Coli- New
IRE INTERNATIONAL CONVENTION, seum & Waldorf Astoria Hotel, York City, Mar. 26-29, 1962.
Clinie, Rochester Univ. of Rochester, Mar. 27, 1962.
QUALITY Soc. for Rochester,
CONTROL
Q.C.; IN: ks
ENGINEERING ASPECTS OF MAGNETO- HYDRODYNAMIcs, AIEE, IAS, IRE, U. of Rochester; U. of Rochester, Rochester, N.Y., Mar. 28-29, 1962.
SOUTHWEST
SHOW; Rice April 11-13,
IRF Hotel, 1962.
CONFERENCE Houston,
AND Texas,
JOINT COMPUTER CONFFRENCE, PGEC of IRE, AIEE, ACM; Fairmont Hotel, San Francisco, Calif., May 1-3, 1962.
HUMAN PGHFE May 3-4,
FACTORS in of IRE; 1962.
Electronics, Los Angeles, Calif.,
ELECTRONICS COMPONENTS CONFERENCE, PGCP OF IRE, AIFE, FIA; Marriott Twin Bridges Hotel, Washington, D.C., May 8-10, 1962.
NATIONAL AEROSPACE Electronics Con- ference, PGANE of IRE; Biltmore Hotel, Dayton, Ohio, May 14-16, 1962.
MICROWAVE Theory & Techniques Na- tional Symposium, PGMTT of IRE; Boulder, Colo., May 22-24, 1962.
December 29, 1961
Advertisement
SPRAGUE'S ALL-NEW TYPE 2N2100
ECDC TRANSISTOR...
| Volt-Second Calibrator for Magnetic
Core Testing
POOR TR Menage ge oe := — eq
The Model 1W22 Volt-Second Calibrator, a recent development of Sprague Electric Company’s Special Products Division, is a_highly- specialized instrument which gener- ates a train of identical pulses.
The volt-second area of the pulses, | continuously variable over a wide | range, is accurately determined at any time by multiplying the current flowing through an associated pre-
square-loop core toroid undergoing a pulse test.
The Model 1W22 is intended for the calibration of electronic inte- grators used in measuring the volt- second areas of “‘fast’’ voltage pulses. It is particularly useful in square- loop core testing systems, including cores such as bobbin, ferrite, and small tape-wound cores.
The flux change in a core under test is determined by integrating the core output response with an elec- tronic integrator. The output of the integrator is proportional to the flux change and can be expressed in terms of volt-seconds or in equiv- alent flux units, such as Maxwells.
The output of the calibrator con- sists of uni-polar voltage pulses of 60 pps, each having a pulse width of approximately 0.5 sec. The actual volt-second area of each out- put pulse from the calibrator mav be varied, from 2.5 to 550 Maxwells, continuously and precisely.
| Model 1W22, housed in a rugged steel cabinet, is intended for bench | use. Model 1W20, for standard rack | mounting, is also available.
For complete technical data, write for Engineering Bulletin 90,100 to Technical Literature Section, Sprague Electric Company, 35 Marshall St., North Adams, Mass.
CIRCLE 200 ON READER SERVICE CARD
cision ammeter by the calibration | constant of the instrument. The wave | mums) which is far superior to any- | shape of the pulses is similar to |
| those which are produced by a |
Head-and-Shoulders Above Any Other Core Driver on the Market Today!
| Sprague Type 2N2100 Germanium
Electro-Chemical Diffused-Collector Transistors, especially developed for
| high current core driver applications,
offer a combination of ratings (with 15 guaranteed minimums and maxi-
thing you've ever seen before.
ECDC construction combines the optimum features of the electro- chemical precision-etch techniques and diffused-collector techniques in one highly-mechanized process. That’s why the 2N2100 meets all of the conditions for an “ideal” transistor.
Compare these characteristics and ratings with those of any other core driver!
Ves —40v Vees 35V Ves -2V —500ma
fre (min. at lec
Sor: = 1.5V) Vce (SAT) (max. atic = 200ma Ip = 10ma) Vee (max. at lc = 200ma 12ua at 15V te = 10ma) 40 at Cob (max.) lc = 100ua fr BVces (min.) 40 tr (nsec. max.) BYVceo (min.) 20 ts (nsec. max.) BV eso (min.) 4 tt (nsec. max.)
le Pa (25°C case)
Pa (25 € ambient) Iceo (max.) BYceo (min.)
750mw 250mw
For complete technical information on Type 2N2100 Transistors, write for Engineering Bulletin 30,401 to Technical Literature Section, Sprague Electric Company, 35 Marshall Street, North Adams, Massachusetts.
*Trademark of Sprague Electric Co. RS rae
SPRAGUE
THE MARK OF RELIABILITY
CIRCLE 33 ON READER SERVICE CARD 33
Highly Reliable HITACHI ‘‘SEMI-CONDU
For Industrial Use Switching Transistors and Diodes
Hitachi semi-conductors provide the basis for the excellent capacity of the Hitachi Electronic Computer
HITAC 103. ‘ 1N344™ 1N35 iIN38AP INS6A . IN60 1$77 | 1$78 1$79 >
we
AR i a tite aig
Se en ek EP E Ei PPPS a BP ee eee
% we
@ am pet 6 aes cas Cable Address # “HITACHY” TOKYO \BBack of HITAC 103.
34 CIRCLE 34 ON READER SERVICE CARD electronics
PULSE POINTERS -
SERVO modular serial word generators offer broad test flexibility for digital circuitry and logic design
Servo’s fully transistorized modular serial word generator standardizes such features as variable sync bit loca- tion, NRZ and complementary pulse outputs into its specifications. This is the ideal instrument for handling a wide range of digital circuitry and logic design problems.
Pulse and NRZ outputs allow use of the equipment for generating variable duration widths, coded logic levels for gating applications, or NRZ data for use in conjunction with digital elec- tronic equipment.
MODEL 5510
Fully modularized construction ena- bles additions or changes of standard plug-in modules to faster rise times, erystal controlled time bases, and higher output amplitudes.
A broad range of special digital instrumentation requirements can be met by using this pre-engineered series as a base, and enlarging and modifying performance using standard broad- function modules to meet specific requirements. Let our pulse specialists analyze your specific pulse problems.
STANDARD OUTPUTS — Set for seven bit word length, 1011100 data
__| clock | | | |
ee PT Le
| Sync
|
att Pulse | |
gag
7
Ul LI
| | Complementary Pulse
NRZ
bes
Flexible basic design features:
® Clock Rate: Pulse spacing continu- ously variable 0.5 to 10,000 usec— 2mce. to 100 cps Syncs: Variable and delayed 80 bit capacity Word length selectable by two 10 position switches—1 to 99 bits
® Arbitrary coding
Clock output 0.2 usec wide, pos. 4.5v into 600 ohms
Complementary pulse output simul- taneous positive and negative out- puts with pulse tops at ground. 12v open circuit 6v into 50 ohms each NRZ
One of 33 cataloged instruments in a broad Electro-Pulse line (which includes as many as 200 standard pulse and digital circuit modules—both tube and transistor type), the Electro-Pulse precision pulse generator couples advanced pulse techniques and cir- cuitry with traditional Servo Corpora- tion instrument quality and reliability.
Fill in coupon for details.
Servo Corporation of America 111 New South Road Hicksville, L. L., N. Y.
Gentlemen:
(] Please send detailed catalog.
‘om |
C) Please contact me for demonstration.
C) Please send me a free SERVO slide rule.
(name)
(title)
(organization)
(address)
(city, zone, state)
Electro-Pulse Products
i”) SERVO CORPORATION OF AMERICA
111 New South Road « Hicksville, L. |., N.Y. +» WElis 8-9700 Sales & service offices coast-to-coast * Representatives in major cities
single pulse generators - double pulse generators - word generators - pulse train and pulse code generators - time delay and gate generators + current generators and core testers - modules
December 29, 1961 CIRCLE 35 ON READER SERVICE CARD 35
DROPOUT PROTECTION
MINCOM SERIES CM-100 RECORDER / REPRODUCER
Data loss from dropouts is practically eliminated in the CM-100, due to this unique system's predetection recording capability. In ordinary post-recording, a dropout more than 6 db down is gen- erally considered a data loss; the CM-100’s operational predetection performance retains such signals through superior phase characteristics and extended bandwidth. Mincom’s CM-100 tecorder/Reproducer, performing longitudinal recording with fixed heads up to 1.5 mc at 120 ips, also offers 7 or 14 tracks, trouble-free dynamic braking, complete modular plug-in assembly, built-in calibration, instant push-button selection of six speeds. Versatile, reliable, a model of simple main- tenance and operation, the CM-100 is tops in its field. Write today for detailed specifications.
Mincom Division 3m MINNESOTA MINING & MANUFACTURING EO.
LOS ANGELES 25, CALIFORNIA + WASHINGTON 4, D.C.
CIRCLE 36 ON READER SERVICE CARD
electronics
electronics
~ December 29,1961
o «
~ -
FIG. 1—Partially disassembled underwater object locator. Front portion mounts transducer and forms beam pattern. Compass pro- vides directional information
Portable Sonar for Frogmen
Has a range of 120 yards with both active-search and passive-listen
modes. Range is presented as a variable audio tone
By I. R. COLLDEWEIH E. L. WALLS R. D. LEE
Dalmo-Victor, Division of Textron Inc., Belmont, California
SCUBA (self contained underwater breathing apparatus) swimmers have always been handicapped in their operations by limited under- water visibility. Only in a few geo- graphic areas is the water clear, and even on bright days the usable light from the sun extends only about 50 feet below the ocean sur- face. In muddy rivers and bays, visibility is reduced to only a foot or slightly more and underwater
December 29, 1961
searchlights are only a partial solu- tion because they are extremely limited in their application.
The portable underwater object locator, shown partially disassem- bled in Fig. 1, has been developed to extend the scuba swimmers ability to locate and identify submerged objects within a range of 120 yards regardless of water clarity. The design provides for two modes of operation; an active-search mode, and a passive-listen mode capable of receiving ultrasonic marker buoy signals.
The
is a
underwater object locator continuous-transmission fre- quency-modulated sonar that pro-
duces a narrow, sharply-defined acoustic beam. The output signal is a linearly decreasing f-m signal whose repetition period is deter- mined by the range scale. Returning echos from _ under- water objects are heterodyned with the transmitted signal and pre- sented to the operator as an audio tone in his water-tight headset. The pitch of the tone indicates the distance to the target; the lower the tone, the nearer the operator is to his object. A magnetic compass that may be illuminated by press- ing a button indicates direction. Thus, the equipment provides both range and bearing information to
37
SAWTOOTH GEN
AMP
POST HEADSET DRIVER
HEADSET
cTor| J
FEEDBACK CIRCUIT
Wl
FIG. 2—F-m oscillator is modulated by the sawtooth generator in the search mode and by manual frequency control in the listen mode
—€\
E
TO BLANKING
+ 3V CIRCUITS
FIG. 3—Sawtooth generator uses a series of emitter followers to reduce output impedance. Sawtooth period is determined by selection of resistor
the scuba diver operating it.
By positioning the active-listen- ing control in the listen position, the operator can use the under- water object locator to locate marker beacons transmitting in the range of 30 to 40 Ke. The operator manually tunes the local oscillator until an audible signal is received. The pitch of the tone is not an in- dication of the distance to the marker beacon, but the direction to the marker buoy can still be de- termined because of the beam pat- tern of the receiving hydrophone. The device is enclosed in a two-part cast-aluminum water-tight housing. The front portion of the housing is an inverted right circular cone that mounts the transducer and forms
38
the acoustic beam pattern. The rear hemispherical portion of the housing contains the printed-circuit board and flashlight battery power supply. The control knobs, headset connectors, and an illuminated com- pass are externally mounted on the housing. Two large guide handles are provided for aiming the equip- ment while in operation. The ob- ject locator is designed to be 3 pound buoyant when submerged to provide for easy handling and di- recting. Seals are used between the case halves and shafts to prevent water leakage into the equipment. The set contains a leak detector to provide an audible signal to the operator in case of failure of the water seals. Two water proof head-
sets provide for the operator and a buddy swimmer.
Figure 2 is a block diagram of the equipment. The sawtooth gen- erator provides a linearly decreas- ing voltage whose repetition rate or period is a function of the range scale. The sawtooth voltage is ap- plied to a voltage sensitive multi- vibrator or frequency-modulated oscillator.
The multivibrator output is amplified to drive the projector por- tion of the transducer. The re- ceiver consists of a balanced modu- lator mixer, slope amplifier, post amplifier, blanking amplifier and headset driver. Signals received from the hydrophone are hetero- dyned with a sample of the trans- mitted signal in the balanced modu- lator, resulting in many sum and difference frequencies. Only the difference between the received and transmitted frequency is used. The echo signal traveling from the unit to the target and return undergoes a time delay resulting in the re- ceived frequency being higher than the transmitted frequency. The greater the distance, the greater the difference frequency and conse- quently, the higher the tone pre- sented to the operator. The rate at which the frequencies are swept in a sawtooth manner is adjusted to permit the difference frequency to be in the audible range for the three range scales of 0-20, 0-60 and 0-120 yards. With experience, the oper- ator becomes proficient in estimat- ing target range, depending on the scale in use.
In the listen mode of operation, a manually controlled d-c voltage is substituted for the sawtooth gener- ator. Additional capacitance is switched into the frequency-modu- lated oscillator to allow the oper- ator to tune over the frequency range of 30 to 40 Ke. The power amplifier, projector and blanking amplifier are switched out of the circuit as they are not used in the listen mode.
One of the major problems in the design of the underwater object locator was to obtain an output fre- quency which varies linearly with time over the temperature range of 0 to 50 C and with variations in battery voltage. Since the range signal presented to the operator is the instantaneous difference be- tween the transmitted and received
electronics
signals, linearity of AF/AT is es- sential to present accurate in- formation as a trained operator can detect linearity variations of less than 1 percent. To achieve the re- quired linearity, temperature com- pensation was introduced in the sawtooth generator and f-m oscil- lator circuits. A schematic is shown in Fig. 3.
The sawtooth period is controlled by capacitor C, and resistor R,, R, or R, as selected by the range switch. Transistor Q, provides a constant current to charge capaci- tor C, The constant current characteristic is achieved by main- taining the base of transistor Q, at a constant voltage obtained from silicon diodes D, and D., operating in a forward-biased condition. Transistor Q, causes capacitor C, to charge negatively while the ser- ies of emitter follows, Q,, Q. and Q, provide high input impedance so that the base of transistor Q, will not load the constant-current cir- cuit. The output of this series of emitter followers is obtained at the emitter of Q, where the circuit im- pedance is low. The output signal from transistor Q, drives the fre- quency-modulated oscillator and the recycle circuit. The recycle circuit blanks the transmitter output at the end of each sawtooth period.
The frequency modulated oscil- lator, is shown in Fig. 4. Emitter follower Q, gives a high input im- pedance while transistors Q, and Q, operate as an astable multivibrator.
Acoustic energy traveling through a water medium is attenu-
ated inversely as the fourth power of distance traveled. The receiver circuit has a sloping frequency- gain characteristic to compensate for this acoustic transmission loss and effectively provide an output signal level independent of range to the target. A schematic diagram of this portion of the receiver cir- cuit is shown in Fig. 5. The re- ceived signal from the hydrophone is supplied to a balanced ring mixer circuit. The instantaneous _ re- ceived signal is mixed with the out- going transmitted signal to produce a difference signal whose frequency lies in the range of 250 to 2,500 cps, dependent upon the range to target. This difference frequency signal is applied to the base of the transis- tor. The capacitor-inductor net- work in the collector circuit pro- vides the _ slope-frequency gain characteristic. The design of this network required consideration be given to the frequency response of the following amplifier stages, as well as the headset response. The net effect of the combination is to produce a constant audible signal level in the headset as the operator swims toward a target. To accom- plish this, the system response in- creases approximately 10 db per octave over the receiver frequency range.
The leak detector consists of a pair of wire electrodes extending from the printed circuit board to the lowest point in the case. Cur- rent between the electrodes due to salt-water conductivity provides a regenerative feedback path around
TO DRIVER
the receiver audio amplifer circutts. Entrance of only a few drops of water is sufficient to complete the circuit and cause the receiver to oscillate at an audible frequency, thus alerting the operator and pre- venting extensive water damage.
The headset design uses a bone- conduction element to withstand the hydrostatic pressures encount- ered at depths as great as 200 feet. The elements are mounted in molded Neoprene ear cushions attached to a beryllium copper headband. Waterproof quick-dis- connect plugs provide for attach- ment of the headsets. The acoustic response of the elements provides a rising frequency response char- acteristic to compensate for the target range, but cuts off sharply above approximately 3,000 cps to eliminate unwanted noise.
The transducer contains a series of concentric rings of barium titanate connected to form the transmitting projector and receiv- ing hydrophone. The hydrophone consists of ten separate elements and the projector six elements. The projector is acoustically isolated from the hydrophone by Coprene rubber spacers. The crystal assem- bly is encapsulated in a Rho-C ma- terial to match to the acoustic im- pedance of sea water, the entire unit is protected by a rubber boot.
The underwater object locator was conceived by engineers at the U. S. Naval Electronics Labora- tory, San Diego, California, who constructed ‘several vacuum-tube models for naval evaluation.
ia I tit]
4 AMPLIFIER
FROM SAWTOOTH GENERATOR
FIG. 4—F-m oscillator can be placed in either the auto- It is an astable multivibrator
matic or manual mode.
December 29, 1961
OUTPUT SIGNAL FROM DRIVER
FIG. 5—Slope amplifier has frequency-gain characteristic to make output level independent of range
39
Semiconductor Functional Blocks
THESE blocks
SEMICONDUCTOR functional perform multiplication or division by a process similar to that
used by a slide-rule. Logarithmic addition or subtraction, followed by extraction of the antilogarithm, gives the product or quotient of two inputs. Forward-biased p-n junc- tions provide the logarithmic rela-
tionship, because in the range where the effects of series and shunt resistances and saturation
current are negligible, diode volt- age is directly proportional to the logarithm of the current. Functional blocks for multiplica- tion were constructed to have an input range of 10 to 1 and an out- put range of 100 to 1. Accuracy was within 5 percent at higher out- puts, with a maximum error of about 10 percent at the lowest out- puts. Built-in temperature com- _ pensation provides stable opera- tion over a reasonable temperature range without significantly increas- ing the heat generated within the block. By applying the same fab- rication processing to uniform ma- terial for all p-n junctions in each
40
block, diodes were produced with identical electrical characteristics.
One functional-block design uses an output transistor, rather than an output diode. This modification gives more useful power output levels than can be obtained from the all-diode block. Multiplication accuracies of the transistor-output blocks are not as good as with the all-diode blocks.
When the logarithms of two quantities are added, the sum is equal to the logarithm of the prod- uct. Thus, if Z = XY, then log Z = log X + log Y.
The forward V-I/ (voltage-cur- rent) characteristic of a_ typical semiconductor p-n junction is loga- rithmic over a considerable range. Where diode series and shunt re- sistance are negligible, the V-/ characteristic of a p-n junction can be described by
I =I, (emer — 1) (1)
where 7 is the current, I, is theo- retical saturation current, q is elec- tron charge, V is the voltage across the junction, k is Boltzmann’s con-
Diode and transistor elements fabricated from monolithic semiconductor
blocks form analog
multiplification
and division circuits
By H. C. LIN, C. E. BENJAMIN, P. W. SMITH, B. S. ARONSON,
Central Research Labs., Westinghouse Electric Corp., Pittsburg, Pa.
stant, 7 is absolute temperature, and vn is a constant involving vari- ous physical processes in the junc- tion region, with values from 1 to greater than 3 for different junc- tions.’ In the region where e‘’’"*’ >> 1, Eq. 1 can be expressed as
InJ/I, = qV/nkT (2) Thus, if J is made proportional to one of the quantities to be multi- plied, V is proportional to the loga- rithm of J.
The equivalent circuit of the multiplier is shown in Fig. 1A. Di- odes D, and D, convert input cur- rents J, and 7, into logarithms V, and V.. The sum voltage V, = V, + V. is proportional to the logarithm of the product /,J.. The antiloga- rithm of V, is the current J, through p-n junction diode D,.
For each diode D,,
Vn = (nkT/q) loge (1m/Tom) (3) Therefore by adding the two loga- rithms of the two inputs and taking the logarithm of the output
Ts = (To3/To1 Lo2) Th 1 (4)
The analysis holds only for d-c
operation. For small-signal a-c
electronics
Perform Multiplication and Division
operation the addition of a-c volt- age drops of known a-c currents passing through diodes does not yield a sum a-c voltage proportional to the logarithm of the product. This is due to a term proportional to the sum of the inputs as well as one proportional to their product, and the former term is usually larger than the latter.
Unfortunately, the d-c character- istic of a semiconductor p-n junc- tion is sensitive to temperature. At room temperature, the J, of a silicon diode will change by about 9 percent per deg C; this change is approximately proportional to qE,/ nkT*, where E, is the energy gap (1.1 ev in silicon).
In the expression for J, in Eq. 4, the proportionality factor is equal to I,3/1., J... Since all of the satura- tion currents have the same tem- perature coefficient, the quantity I 4s/Io. Toe is as temperature sensitive as any one saturation current alone, that is, it will vary by about 9 per- cent/deg C.
To compensate for this tempera- ture variation, another p-n junc- tion diode, D,, is introduced (Fig. 1B). If J,, J., J;, and J, are the for- ward currents through the four re- spective diodes, and /,,, I.., I.., and I,, are the theoretical saturation currents of these junctions, output current J, can be shown to be
_ I tet hls : I; = (i: i) x I (5)
Because the saturation currents all have approximately the same tem- perature coefficient, the quantity in parentheses will not vary with tem- perature. Thus if J, is held con- stant, then /, will be proportional to the product /,/J,. For best accu- racy, good thermal coupling should be maintained between the four di- odes to equalize the temperature. A monolithic structure provides in- timate thermal coupling within the semiconductor crystal.
For maximum accuracy inde- pendent of temperature (7), both (OV/0O log I); and (OV/0OT), must remain constant. Measured curves of V versus J as a function of T and
December 29, 1961
V versus T as a function of J for a typical forward-biased diffused sili- con diode are shown in Fig. 1C and 1D. These relationships hold except at relatively high temperatures and low currents. The diode whose characteristics are shown has a junction area of 0.19 square inches, and would be used in a multiplier/ divider block as D,, D., or D, at rel- atively high currents, to avoid op- eration in the low-current range. Smaller-area diodes, such as those more commonly used in the func- tional blocks, would not show devia- tions such as shown in Fig. 1C and 1D until higher temperatures or lower currents, because these devia- tions are due to the —1 becoming significant in Eq. 1; this effect be- comes more pronounced with in- creasing /,, and this current is di-
BD, V3yt Vi +V2
Ploue
(Cc)
100pu0 CURRENT
™)
DIODE VOLTAGE
rectly proportional to the area.
The arrangement of the junc- tions shown in Fig. 1B involves ohmic interconnections of ” regions to p regions at points a and b. On the other hand, in Fig. 1E all four diodes are connected back-to-back (p region connected to p region and n region connected to n region), and no external interconnections or separate interconnection regions are needed. For fabrication in a monolithic block, this is the most desirable arrangement, even though no common connection is permitted between the two input circuits.
If an appreciable portion of either input current shuld flow through the output branch instead of the desired input diode, accuracy would be impaired. Output current I, in Eq. 5 would then be modified
Vv IN VOLTS
1 40 50 60 70 80 90 TEMPERATURE IN DEG C
DEVIATION DUE TO SERIES RESISTANCE
DEVIATION DUE TO SATURATION CURRENT
LOGARITHMIC RANGE
/ ‘
"Shaaaaas DUE TO SHUNT RESISTANCE
(E) (F)
CURRENT (LOG I)
FIG. 1—Basic multiplier (A); with temperature-compensation diode added (B). Curves for silicon diode in (C) and (D) are for V versus I and V versus T, respectively. Configuration of diode multiplier in (E) aids fabri- cation. V-I curve for typical Si diode (F)
41
DIODE VOLTS (Vv)
0.2
1
MONOLITHIC BLOCK
= |
MILLIVAC VY }MV270 O-C pv
a - nn
(a) Z 5.
CURRENT {I)
(Cc)
ae
pon ee er a ee
FIG. 2—Construction and equivalent circuit (A) of 4-diode multiplier-divider; V-I characteristics of its diodes (B). Test circuit for checking multiplication characteristics (C)
as
aie? (I, Is) (Is—1s) n= (Feit) x Uti) ©
Equation 6 shows that for accurate multiplication J, should be very small compared with /,, J., and J,.
The specifications for ranges of operating values were one decade for each of the inputs and two dec- ades for the output. Therefore, since I, is derived from the current ‘sources for J,, J, and J,, J, should be less than 1/100 that of J,, J, and J, so that the loading effect is insig- nificant. If we insert this require- ment into Eq. 5 by making J, I., and J, = 100 J,, then Jus To/To. Ice = 0.01. The saturation currents I,, are proportional to the junc- tion” areas of their respective di- odes. If D,, D., and D, have equal areas, Eq. 5 will be satisfied by making the area of D, 1/100 that of the other diodes.
All four diodes must exhibit the desired V-I-T relationship over the full ranges within which they will operate. In a forward-biased p-n junction, the V-log J proportionality does not hold at low currents where the operating current is small com- pared to the saturation current (that is, where e‘” ~ 1 in Eq. 1, where * = q/nkT) or to the shunt leakage current. Operation at greater than approximately 0.2 volt (so that e“” >> 1) !s neces- sary. To minimize effects of shunt-
42
leakage current, proper junction fabrication techniques must be used, along with mechanical protec- tion and surface stabilization at the junction periphery.
At high currents, the series re- sistance predominates over the logarithmic relationship, and the voltage drop in this region is linear rather than logarithmic. These ef- fects are shown in Fig. 1F, where log J is plotted against V for a typi- cal silicon diode. For a diffused- junction diode, a low series resist- ance is obtained by making the junction area (particularly D,) large and the thickness and resis- tivity of adjacent semiconductor material low. The resistance of out- put current meter, J, in Fig. 1E, should be as small as possible.
It is important that all four di- odes exhibit the same logarithmic slope (dV/d log I). From Eq. 2 it can be seen that the multiplication operation
(h/To1) (I[2/To2) = Is/Tos (7)
is obtained by making eFV1 y ekV2 = ekVs (8) where * = q/nkT and is inversely proportional to the logarithmic slope. Therefore accuracy does not depend on the value of *, as long as it is identical for all of the diodes, but if logarithmic slopes should vary among the diodes in a block, serious errors will be introduced. Several basic physical phenomena
are involved in making x different from the value of unity used in Shockley’s original analysis of p-n junctions.* Recombination within the p-n junction space-charge re- gion’ will produce adjacent por- tions of the forward characteristic with n = 1 and n = 2; however in practice the distinction between these regions is so obscure that a considerable region often exists with a value of n constant at some value between 1 and 2. For more abrupt junctions, internal field emission’ will result in even higher values of n and excessively high values of J,. However, the struc- tures have extremely graded junc- tions, with correspondingly low fields, and effects from this phe- nomenon appear to be negligible.
For silicon diodes made by vari- ous processes, logarithmic slopes have been observed from 0.08 to 0.18/current decade, corresponding to values of n from 1.3 to 3. How- ever, by using uniform semiconduc- tor material and processing all four diodes identically, uniform loga- rithmic characteristics can be con- sistently obtained. All of the dif- fused junctions used in multiplier/ divider functional blocks exhibited logarithmic slopes of approximately 0.09 v/current decade, correspond- ing to an n of 1.5.
Details of construction and the equivalent circuit of the four-diode
electronics
multiplier/divider are shown in Fig. 2A. The monolithic block was fabricated from a wafer of low re- sistivity silicon of overall dimen- sions * in. x 2 in. x 0.006 in. The block has a p and an n layer. Metal foils are alloyed for ohmic contacts and reduction of thermal resist- ance. Region isolation is provided by the troughs.
To determine the quality of a completed multiplier, the forward V-I characteristic of each diode was measured for the four diodes of a typical unit (Fig. 2B). Each diode must be operated in a region of its characteristic curve linear on this graph. For diodes D, and D., a straight line region of one current decade is necessary; for D, two cur- rent decades are required. The cur- rent through D, is set to permit op- eration of D. over its best two- decade region, while allowing D, and D, to operate at current levels that are as high as possible. This adjustment feature allows multi- plier/divider functional blocks with diodes of different characteristics to be set for operation in their op- timum regions without additional circuits.
Inputs to D, and D. were 0.2 ma to 2 ma, with D, driven from 1 ya to 100ua. The current required for D, is that which causes 1 ya of cur- rent through D. when D, and D each have a current of 0.2 ma. When J, and J, are each 0.2 ma, V, and V are each approximately 0.35, for a total of 0.70. The voltage across D should be about 0.24 to cause /, to be 1 wa. Thus, bucking voltage V, must be 0.70 — 0.24 = 0.46v. A current through D, of 1.1 ma pro- duces V,.
Multiplication characteristics were checked in the circuit shown in Fig. 2C. Each input current was varied independently over its full one-decade range, and output cur- rent was monitored by the d-e mi- crovoltmeter, which measures the voltage drop resistor R,. Output current, which is propor- tional to the product of inputs / and J., was then obtained by divid- ing the measured voltage by the re- sistance of R,.
Figure 2B shows that the d-c re- sistance of D, at the bottom of the operating range (1 pa) is 2.5 x 10° ohms, and at the top of the operat- ing range (100 pa) it is 4 x 10° ohms. Therefore, the voltage drop
across
December 29, 1961
across R,, a 10-ohm resistor, is neg- ligible.
The analog multiplier can be used as an analog divider by having the input currents fed to diodes D, and D, of Fig. 2C. The combined voltage is (V, — V,), a logarithmic difference, corresponding to the logarithm of the quotient in divi- sion. Diode D, supplies the anti- logarithm as /,, thus producing an output current proportional to the quotient of the input currents. Di- ode D, is used for temperature com- pensation and bias.
A typical unit exhibited division accuracy within 5 percent for about 14 decades; at higher output cur- rents series error was introduced
'
|
|
|
1
!
| ——_—— ot, MONOLITHIC
BLOCK
—Diode-transistor
Vy )
Pa. » multi-
plier-divider block and test circuit
as the output current became com- parable to that of one of the inputs. This problem is more serious with dividers than with multipliers, since in multiplication the maxi- mum output current is obtained only when both inputs are at their maximum, with division maximum output is obtained with one of the inputs at its minimum. Input diodes that are logarithmic at higher currents would eliminate this error.
As in multiplication, the output diodes must be logarithmic two decades if the inputs are al- lowed to vary independently over one decade each in division. Since diodes D,, D., and D, all have the same area in this design, the unit can be used for either multiplica- tion or division by interchanging D, and D, for the input and tem-
whereas
over
perature-compensating.
The output information from the four-diode multiplier/divider func- tional block is difficult to work with in practical circuits. Being a d-c voltage in the microvolt range, such information requires d-c amplifiers to raise the output to a level that can be used in the conventional cir- cuits of computers or controls. Since the transfer characteristic of a transistor (Jwu.-V;,) is also logarithmic, a transistor can be substituted for the output diode of a four-diode block (Fig. 3). Tran- sistor output current /. is propor- tional to the product of the two in- put currents, requiring no auxiliary circuits for practical applications. This transistor is incorporated into the monolithic block in place of the output diode. The inherent current gain of the transistor allows its input current to be small enough to be negligible with respect to the input diode currents, while the out- put current can be at usefully high levels and is relatively insensitive to load. The transfer characteristic generally does not depend upon cur- rent gain fall-off at low currents in the transistor.
Multiplication accuracy of the al- loyed emitter multiplier divider block is good. Curves of V-J-T have also been measured for the transfer characteristics of transistors being fabricated within multiplier ‘divider blocks. Although the families of curves are not as linear and parallel as those for simple diodes, they are of the same general character and tend to provide the same tempera- ture compensation.
The work described here part of the Molecular Electronics Program under Air Force Contract AF33(600)-39378. The authors thank E. M. Black and G. Machiko for valuable assistance in fabrica- tion and testing.
was
REFERENCES
(1) J. L. Moll, The Evolution of the Theory for the Voltage-Current Character- istics of P-N Junctions, Proc IRE, 46, p 1,076, June 1958.
(2) H. C. Lin and R. E. Crosby, Jr., A Determination of Thermal Resistance of Silicon Junction Devices, IRE Nat'l Conv Record, 1957, part 3, p 22.
(3) W. Shockley, The Theory of P-N Junctions in Semiconductors and P-N Junction Transistors, BSTJ, 28, p 435, July 1949
(4) C. T. Sah, R. N. Noyce, and W Shockley, Carrier Generation and Recom- bination in P-N Junction Characteristics, Proc. IRE, 45, p 1,228, Sept. 1957.
(5) A. G. Chynoweth and K. G. McKay, Internal Field Emission in Silicon P-N Junctions, Phys Rev, 106, p 418, May 1957.
43
ILLUMINATION STABILIZER
for Photosensing System
Feedback circuit generates precise pulses to control light levels of light-sensitive devices that
use a lamp as the light source. Feedback loop obviates elaborate circuits usually associated with
switched control stabilizers
By J. R. DYKE, Computer Developments Limited, Middlesex, England
(A)
FIG. 1
? CONTROL :
ELEMENT
AMPLIFIER MEASURING
ELEMENT
REFERENCE
FOR RELIABLE OPERATION of the pho- tovoltaic system in a punched-card or punched-tape reader, the illumi- nation level of the card at the read- ing station should be constant.
Stability control includes lamp output in the feedback loop (A) and uses transistor as a control element (B)
REFERENCE (SLICING) LEVEL
TIME
nd (A) OUTPUT FROM PHOTOVOLTAIC CELL
TIME
(B) oirterence BETWEEN CELL OUTPUT AND REFERENCE AFTER AMPLIFICATION
| IME
(C) wioth contRoLten PULSES GENERATED BY SLICING THE WAVEFORM OF (B)
FIG. 2—Waveforms of pulses generated by light stabilizer
ag
Where the light source is a low- voltage tungsten-filament lamp sup- plied through a transformer from the main power supply, constancy of light output cannot be assumed.
Variations in illumination have been due to variations in main power supply and individual differ- ences between bulbs, changed regu- larly to avoid failures.
For a_ constant illumination source, not affected by changing bulbs, it is not enough to stabilize the voltage across the bulb or the current through the bulb, instead, the feedback system must include the light from the bulb in its con- trol loop, see Fig. 1.
Photoelectric cells, already used in the reading stations, were chosen for measuring the _ illumination level. Sensitivity of the cells is sub- stantially independent of ambient conditions, and they are rugged.
However, control for the lamp current presented a problem. Mag- netic devices were ruled out because of weight, bulk and expense. Sili- con controlled rectifiers were almost as expensive, and required more complex circuits. So transistor con- trols were chosen.
In a simple control arrangement, the base of a transistor may be sup- plied with a steady control current, or with pulses that switch the tran- sistor on and off. A resistor placed
‘across the transistor reduces dissi-
pation and, in the switched system, limits the peak voltage appearing across the transistor. Less power is dissipated in the transistor, espe- cially if the switching rate is low, but this usually requires a more
electronics
S2T! ZENER REF DIODE
J sal
N
P. Vv. CELL FERRANTI MSI
FIG. 3—Complete circuit of stabilizer.
complex amplifying circuit to gen- erate switching pulses of control- lable width. Since a 48-watt bulb was to be controlled, dissipation in the transistor was important, so a simple method for producing the required pulse was devised.
Pulse generation of the stabiliz- ing circuit (Fig. 3) is illustrated by Fig. 2. Light output from the bulb contains about 1 percent of 100-cps ripple, which lags nearly 90 deg on the 100 cps component of the sup- ply to the bulb because the thermal time constant of the filament is much longer than 0.01 sec. The dif- ference between the current from the photovoltaic cell in Fig. 2A, and the reference current, is amplified to the waveform in Fig. 2B. Apply- ing this pulse to a slicing transistor (Q. in Fig. 3) produces the width- controlled pulses of Fig. 2C. Pulse widths of this train increase with a reduction in the mean level of illumination, so that after amplifi- cation, these pulses drive the con- trol transistor (Q, in Fig. 3).
The circuit is polarity sensitive, not waveform sensitive. If the pho- tocell is connected the wrong way, feedback will be positive instead of negative, and the light output will not be stabilized.
In the stabilizer circuit, Fig. 3, the reference current is supplied from the Zener diode through R, and R,,. The difference between this current and the current from the photovoltaic cell is amplified by Q and applied to the base of Q.. These pulses are amplified by Q,, Q, and Q., and supplied to Q,.
The range over which the illumi-
December 29, 1961
—6.3V
Difference between reference current supplied by zener diode and current from photocell is amplified by transistor chain, and then supplied to control element Q, to adjust lamp current
nation is stabilized extends from the point where, with Q, conducting all the time, there is only enough current flowing to provide the re- quired illumination—to the point where, with Q, off all the time, too much current will flow. This range is determined by the transformer secondary voltage, and the value of R,,. The variation of illumination over the controlled range is equal to the percentage of ripple in the output of the bulb, usually one per- cent peak-to-peak.
Transistor Q, carries the full lamp current when conducting but, as it is saturated at this time, the mean dissipation is low. This is an important feature of the circuit.
The transformer power supply is followed by a full-wave rectifier so that the transistor deals with a unidirectional current. Thus the ripple problem is not aggravated by half-wave action.
The photovoltaic cell is mounted to obtain a mean short-circuit cur- rent of approximately 1 ya at the illumination level.
Nominal component values should not exceed the following tolerances: +5 percent variation of all resis- tors except R, and R,,; +5 percent variation in d-c supply voltages; 8 variation of GET872 transistors down to 20; 8 variation of GET571 transistors down to 20 at a collector current of one amp; 8 variation of GET572 transistors down to 15, at a collector current of 4 amp.
The dissipation in Q, is less than 2 watts; in Q., less than 200 mw. In each of the other transistors, dissipation is less than 10 mw.
Circuit stability is primarily de- termined by the stability of the reference current and of the photo- cell sensitivity. Drift can be caused by dust on the photocell or on part of the lamp facing the photocell, or by change in the leakage current of Q,. The cell must be mounted so that the sensitive area is not obscured by dust, while Q, is selected for low leakage. A silicon transistor can be used only if the circuit is modified to allow for the increased base- emitter voltage required to drive the silicon device.
The percentage of ripple in the light output of the bulb is the main factor determining the precision of the system. Since precision is in- versely proportional to the percent- age ripple, precision may be in- creased by smoothing slightly the output from the rectifier, or using a bulb with a longer time constant.
Precision is also dependent on the effectiveness of Q, in controlling the filament current. This is op- timum if Q, is arranged to be switched off during the time when the voltage from the rectifier is maximum. This operation, which also minimizes the ripple in the light from the bulb, is secured auto- matically because of the 90-deg phase lag introduced by the long thermal time constant of filament.
Effectiveness of control may be improved by increasing the value of R,,, but this increases switching losses in Q,. The precision of the system is independent of the gain of the transistors, providing this gain is sufficient to secure rapid switching of Q,.
DIGITAL CIRCUITS
Achieve Automatic Control
of Radar Range Tracking
Tracking modern high-speed targets imposes tremendous demands on radar systems. This digital system locks its range gate onto
the target and holds it there, adjusting the range gate with every
target movement, and producing a highly accurate range readout
By DARRELL L. NEPVEUX, Advanced Electronics Center, General Electric Co., Ithaca, N. Y.
ACCELERATION COMMAND
“TRACKING GATE (B)
FIG. 1—Only one ranging counter is shown in digital range tracking sys-
. tem (A). Pulse diagram (B) indicates relationship of tracking gate to main
46
bang
ALTHOUGH modern long-range sys- tems bear a basic resemblance to their ancestors, many new and mod- ified techniques have been made necessary by the extended require- ments of such systems. In first generation radars it was sufficient to look with the receiver system at any and all video returns between two radar transmission pulses. Range data was processed by the operator noting the track of a spe- cific video return pulse on a ppi cro. In using modern long-range radars, such techniques are no longer feasi- ble for these reasons: although radar range has been greatly ex- tended, the video of interest is normally confined to a small seg- ment of overall range; the ex- tended range usually requires a round-trip propagation time that extends over several interpulse periods of the radar prf. Due to the high performance capabilities of targets automatic tracking of
electronics
7" i PBR woe! Fe
a |
-
= E
‘At Ac eA Ae 2
t :
tae a -
‘
¥..._ A... YE...
. 4
ae NS
4
Master display and control console for pincushion radar set contains digital range tracking system, which is in cabinet
at right of operator
target-return video is necessary.
This article describes a digital automatic range-tracking system that tracks a single target or cluster of targets. The system defines range by surrounding a video (or group of video) return(s) with a tracking gate (Fig.1). A tracking gate may be manually c~ automatically placed or moved tc any position within overall range. In typical operation, the operator first cranks range in- formation into the system and then automatic tracking takes over the control of the tracking gate, which then follows the target through every range change.
To obtain accuracy and resolu- tion in range control, the control functions are implemented by digital logic and circuits. The range value (in ft) of a single binary bit in a digital system is derived from: ft of range/bit =
propagation velocity
“2 x clock frequency |
December 29, 1961
Thus, maximum range of the sys- tem is prescribed by a sequence of binary-arithmetic bits. The range value of a single binary bit deter- mines the maximum bit length of the binary sequence that is neces- sary to provide the maximum range of the system. Any point within the range is resolved to the ac- curacy allowed by the range value of a single binary bit. Placing the tracking gate in a range position is accomplished by counting out a specific binary number and relating the elapsed time of the count to the predetermined point in range. The tracking gate is moved by changing the binary number, either manually or automatically.
In Fig. 1A, the ranging counter controls the R (or range) param- eter (Fig. 1B) and the tracking gate width counter controls the W (or gate width) parameter. The video-integrator-difference detector block and the tracking loop provide
the automatic movement of the tracking gate by changing R; a manual input to control R is also shown.
The primary components of the system are the ranging counter and the memory counter. In operation, digital range information goes from the memory counter to the ranging counter, which then counts clock pulses.
The memory counter is the binary storage area, which con- tains at all times the digital equiv- alent of range R (Fig. 1B). It is a static counter, since the only allowable changes in its content are controlled by the operator’s variable control or the automatic tracking loop input. Maximum operating speed of the memory counter is dictated by the maxi- mum rate at which corrections in binary value of range are to be made. This speed is nominally an order of magnitude less than the
47
LOGIC OuTPUT ™
DIODES 0;,02, 03, 04,05 & Dg ARE IN65S9'S K=X 1,000
GATING OUTPUT
y iN277
GATING LINE
CLOCK / TRIGGER LINE LINE
RESET
FIG. 2—High-speed buffered flip-flop of ranging counter
clock frequency. The memory counter is a_ reversible counter since both an increase and decrease _in decimal range must be _ per- mitted. Binary range information held by the memory counter goes to external processors or recorders, as well as to the ranging counter.
Generation of a signal pulse that indicates the beginning of the tracking gate is performed by the ranging counter. This counter is an n-Stage shift register, which can count to the maximum value of range, and operates at the system clock frequency. Counting in this unit is done dynamically. The unit begins to count clock pulses at the appearance of a radar transmission pulse and continues to count until a number of clock pulses equivalent to the decimal range has been ceunted. At this point, it generates a signal pulse which starts the tracking gate.
To provide a high range-resolu- tion capability, the clock pulse fre- quency is high. Clock frequencies in the 1 to 10 Me range are usually specified. These clock pulses are counted in the ranging counter, which is composed of a series of transistor flip-flop stages. The first stage of this register must there- fore count at the rate of the sys- tem clock. This stage, a high-speed buffered flip-flop, is shown in Fig. 2. Buffering is used in this circuit to increase the load-handling cap-
48
ability and maintain operating speed.
The counting technique in this portion of the system provides the least complicated performance of the ranging counter. The technique allows the ranging counter to start from a preloaded condition with the restraint that the number of clock pulses necessary to take the counter from its preloaded condition to its full condition (when all of its stages are in the ONE state) is equivalent to the decimal range. This restraint is met by taking the complement of the decimal range and preloading this into the rang- ing counter. Since the decimal range value is contained in a parallel binary form in the memory counter, it is simple to complement each digit of this binary number and preload the complemented decimal range into the ranging couniers. The ranging counter can then be turned on by the trans- mission pulse (main bang) of the radar, count clock pulses until it reaches a full count, then generate a carry pulse that fixes the location (in time, relative to the radar transmission pulse used to start the counter) of the tracking gate. The ranging counter functions as an asynchronous counter having a high-speed counting capability in its first few stages. Although the ranging counter functions asyn- chronously as a unit, its first few
the high
stages run synchronously (this was required to implement another function).
Since the ranging counter tabu- lates the elapsed time between a main bang and the desired begin- ning of the tracking gate, it is necessary to use the main bang to initiate counting in the ranging counter. However, the maximum range of the radar may include several interpulse periods of the radar prf. Therefore, there must be sorting or counting of radar main bangs before they are used with the ranging counters.
Figure 3 shows how this is per- formed. The radar main bangs are accepted into the system seri- ally, on a single line. System spe- cifications dictated the number (m) of the parallel ranging count- ers necessary to cover the maxi- mum range. Each counter is started sequentially, in the 1 m sequence, by a main bang. Only a single such ranging counter ap- pears in Fig. 3. The main bangs are divided in a 1/m counter to provide the sorting, with one main bang being fed to each ranging counter in sequence. Each main bang sets a_ start-stop flip-flop which, when set, opens a clock gate allowing clock pulses into the rang- ing counter which has been pre- loaded. (There are m flip-flops, clock gates and ranging counters.) On reaching a full condition, the ranging counter generates a carry pulse which resets the flip-flop, closing the clock gate and putting the ranging counter in condition to accept the next preloading of complemented decimal range. All
RANGING COUNTER
(n STAGES)
OCcK
L TRIGGER GATING LINE
BANGS
FIG. 3—Inputs and outputs identi- fied as 2 to m would go to other ranging counters that are not shown
electronics
INVERTER
AMPL
TRACKING GATE
(HALF INVERTED)
INTEGRATOR
| GATE OR Q.
2 2N706
FIG. 4—Output of this video integrator
preloading is accomplished at the command of a trigger pulse that occurs at some convenient time previous to the main bang used with the ranging counter.
The carry pulse generated by the ranging counter is now positioned in time at the point where, the tracking gate will begin. Since each of the m ranging counters
provides a carry pulse, and these occur in a serial time sequence, the OR bléck combines all of the carry
pulses on a single line, and delivers tracking gate triggers to the track- ing gate width control.
The tracking gate triggers are generated at a rate equivalent to the radar prf. If the information contained in the memory counter is not changed, the position of the tracking gate will not change.
The tracking gate width control provides some video return pulse selectivity and allows for the dis- persion of video pulses over a pre- determined range increment. The technique that provides this con- trol is identical to the technique that provides tracking gate place- ment. The operator throws a switch that supplies information, in parallel binary form, that deter- mines the width of the tracking gate. Since it is proper to expect the same resolution of the tracking gate width as obtained in the place- ment of the tracking gate, the range value of a single binary bit is identical to its value in the rang- ing counter, and the same clock frequency is used. Since the gate width counter is triggered at the
December 29, 1961
goes to difference detector
radar prf rate, only one such unit is necessary.
The memory counter controls the location of the tracking gate. In- formation is stored in the memory counter in binary form; therefore, all changes inserted into the mem- ory counter must be in binary form. To comply with the requirements of the system, changes in the con- tents of the memory counter are allowed in two modes: manual and automatic.
The method used in the manual mode is range-rate control and is the one preferred from a human- factors standpoint. The operator has one control that controls the frequency of a pulse source fed into the memory counter. Operating at any one frequency results in a con- stant rate of change of range, since a constant stream of pulses is fed into the memory counter, each pulse representing a single binary bit value of range. This method presents the advantage to the oper- ator of continuous control over movement of the range parameter without physical action, with the disadvantage of requiring a second source of information on the value of absolute range. This disad- vantage is overcome by providing a decimal readout of the range value.
The automatic control of infor- mation entered into the memory counter is determined by the track- ing loop. The requirement placed upon the system in the automatic tracking mode is that it maintain a predefined spatial relationship be-
tween a single video, or group of video, and the tracking gate, under specified conditions of target- return video velocity and accelera- tion. This requirement means that the tracking gate is centered on the video pulses appearing within its limits.
The operation of defining the center of the tracking gate is per- formed in the tracking gate di- vision block. This block receives manual gate width control informa- tion. The tracking gate division block contains a binary shift regis- ter into which this parallel-binary gate-width information is fed. The size of this shift register is such that the least significant binary digit of the width of the tracking gate is not entered into the regis- ter. Thus, a binary division by two is performed and counting out this register with clock pulses will -ause a carry pulse to be generated at the center of the tracking gate. The center of the gate is defined to a resolution of one bit value of range. The other inputs to this division block are the tracking gate trigger (indicates the beginning of a tracking gate), the carry pulse from the tracking gate width counter (indicates the end of a tracking gate), and the system clock. The outputs of the division block are three pulses, indicating the beginning, center, and end of the tracking gate.
Since the tracking-gate center is defined, it is possible to determine the video contents of each half of the tracking gate. To restrict the
49
influence of noise on the tracking loop, a video-signal-plus-noise-inte- gration method was used. The triggers of the tracking-gate-divi- sion block open two separate but identical integrator circuits. One of these integrator circuits is shown in Fig. 4. The first inte- grator accepts all of the video and noise signals within the first half of the tracking gate and performs a voltage-time integration, which yields a certain result. The second integrator performs a similar func- tion to the interval of time inclosed by the second half of the tracking gate. The results of these two integrations are then compared, providing two possible conditions: first, the two volt-time integrations yield identical results which means that either there is no video in the tracking gate or that it is properly centered; second, the integrations are not identical, which provides an error signal of proper polarity to cause the tracking gate to center on the video. Performing the inte-
gration function on the raw video and noise effects peaks.
reduces the random introduced by the noise The output of the video integrator and difference block is an error signal of proper polarity for use with the remaining com- ponents of the tracking loop.
The input to the tracking loop indicates the position of the video that must be tracked (it is in one of two halves of the tracking gate); at the other end of the loop is the memory counter. The rang- ing counter, tracking gate width counter, and tracking gate division components have no effect on the tracking dynamics, since their in- fluence is contained within a single tracking period, (where tracking period is defined as the time be- tween two adjacent main bangs). The memory counter, however, has a continuing effect on the tracking loop. Operating as a digital com- ponent, it is a position integrator.
The analysis begins from the tracking gate position. This is the contents of the memory-counter position integrator (since a paral- lel binary format is used). The position integrator is a binary shift register that accepts binary correc- tions and performs a binary inte- gration of these corrections. Thus,
50
on a long-term basis, the correc- tions provided to the position inte- grator must be a true indication of the velocity of the video being tracked; for example, video target pulses with constant velocity can be successfully tracked only if a con- stant number of range unit correc- tions are entered into the position integrator at the initiation of each cycle.
Some measure of tracked velocity must be obtained from the preced- ing components of the tracking loop for use with the position inte- grator. This uses the velocity inte- grator and stabilization network. The error signal output of the video integrator and difference detector is used as an acceleration command to the tracking loop. An integra- tion of these commands provides the tracked velocity information. This integration is performed in the velocity integrator. If a Bode diagram is drawn for the system, it would show the single, 40-db-per- decade slope caused by the two inte- grators in the loop, the position integrator and the velocity inte- grator. Since the zero-gain line is crossed at a slope of 40 db per decade, the system will not appear to be stable. This is the reason for the inclusion of the stabilization network, a lead network which provides an overall Bode diagram with a 20-db-per-decade slope at the zero-db crossover point.
The operations that must be performed by the velocity inte- grator and stabilization network on the error signal to yield the proper inputs to the memory counter (posi- tion integrator) can be implemented in either an analog or digital man- ner. The analog implementation, the least complicated of the two, requires conversion of the error signal pulses to an analog quantity. The integrator is a ca- pacitor and the stabilization net- work is a resistor-capacitor com- bination providing a wide range for selection of time constants. Digital implementation of the integrator is similar to that of the position integrator and can use the error signal pulses directly. The digital stabilization network is more com- plicated to provide the proper range of time constants.
The velocity performance of this
digital tracking system in the auto- matic tracking mode is a direct function of the maximum number of correction pulses that may be entered into the memory counter in one correction cycle, the number of correction cycles in one second and the range value of one correc- tion pulse. This last quantity is determined by the system clock frequency. Since the _ tracking gates are generated at the prf rate of the radar, the correction cycles per second will be equal to the radar prf. Therefore, the only parameter available for specifica- tion is the number of correction pulses per correction cycle, a quan- tity easily manipulated to meet system specification.
A similar approach yields infor- mation on the acceleration per- formance of the tracking loop. The important consideration is the time rate of change of velocity. In de- termining this factor, the weight- ing of the acceleration command and the time constants of the sta- bilization network are of prime importance. It is relatively simple to make changes in the velocity and acceleration capability of the track- ing loop. This is due to the digital nature of the data being processed in the tracking loop.
The system described above is truly minimal. A complete digital range tracking system would have many necessary and useful aux- iliary functions not mentioned. A few of these are visual range dis- plays and display triggers, auto- matic radar prf control, provisions for multiple tracking gates, auto- matic coasting on loss of video, and rate-aided manual acquisition. While these functions require extension and modification of some of the techniques covered, the components and techniques that are described are the primary require- ments of a digital range tracking system.
The digital range tracking sys- tem described has been designed and built, and is operational as a component of the Pincushion Radar system. This effort was part of a contract from the Advanced Re- search Projects Agency, as a proj- ect of RADC. The work was done on a subcontract for Raytheon, Inc. on the Pincushion Radar Project.
electronics
CAMERA PERISCOPE FOR
Cathode-Ray Tube Photography
Design of optics for photographing a crt display is straight
forward. An engineer working on the electronic system
complete the task by following explanation presented here
By DANIEL LEVINE,
Staff Scientist Lockheed Missile
and Space Co., Sunnyvale, Calif. IN PHOTOGRAPHING a radar, tele- vision or oscilloscope display, the camera may either be in-line with the cathode-ray tube, or the light path many be folded in a camera periscope, see Fig 1 (left). The latter arrangement is widely em- ployed to obtain more compact packaging or to permit simultan- eous viewing of the display by use
of beam splitters. The following ex- planation eliminates tedious com- putations in periscope design.
In Fig 1 (top center) the tri- angle represents a cross section of the outer limit of the cone of light between the crt face plate on the right and outer lens element on the left. All rays which enter the camera lens from the phosphor lie within this cone. It is important to note that the distance from the tube to the apex of the cone is not
A--4 CAMERA !
| CRT
! ¢-----[ >
OUTER LENS ELEMENT
PLANE OF PERISCOPE MIRROR
equal to the distance from lens to object used in the lens equation. The distance L, between the front lens element and the crt must be measured on an experimental mock- up, or else computed by means of the lens equation with allowance made for the length of the lens. Then the height of the cone, L, is determined by similar triéngles: as seen in Fig. 1 (top center). Then B= L, Ly Pu
= or L = (1) Pu PL Py ~ PL
15 a IN DEGREES
FIG. 1—Alternative arrangements (left) for photographing a display: (A) single bend, (B) folded optical path, (C) off- set camera indicator. The bounding cone (top center) is determined by the active sweep on the crt and the outer lens limit. Periscope installation (bottom center) between camera and ert with view of the elliptical intercept. Axes
of the ellipse are at right
December 29, 1961
51
10 5 20 a DEGREES ——> FIG. 2—Displacement of the center of the ellipse from the optical axis
OUTER APEX LENS
OF cm: CONE
DIMENSIONS IN INCHES
"IG. 3—Periscope design
2
Bae LENS
ELEMENT 7 FACE (A) = 0.3 IN OF CRT
LOWER
REFLECTOR REFLECTOR
the cone semi-angle, denoted bya, is equated as,
=_, Om a = tan L (2) The function of a periscope mir- ror is to bend all the light rays in the cone of Fig 1 (top center) through an angle of 90 deg. Thus, the sketch of Fig 1 (bottom center) reproduces the bounding cone of light, that has an elliptical inter- cept with the plane of the periscope mirror. This ellipse is the smallest surface that can reflect all the usable light emitted by the ert. When it crosses the optical axis a distance L, from the apex of the cone, its semi-axes are
a Vv 2 tana = 3) L, 1 — tanta ( b 1
-_ —_ (4) L, Vv cot?a — 1
so that the axial ratio is a 2 3 b- V 1 — tan’a °) In Fig 1 (bottom center), the center of the ellipse is not on the
optical axis, but displaced x.. The offset distance is,
, 1/9 b
» > Vv « 9 +) - =wvV2 (¢
Ly cota — 1 ({:) ;
The axial values may be read from the graph of Fig 1 (right), while the offset between the center of the ellipse and the optical axis is plotted in Fig 2.
As an example, a 5-inch ert with a usable sweep length of 4.6 inches is to be photographed with a 35-mm F/2.3 lens, and the measured value of L, for the desired image size is 12.20 inches. A two-reflector peri- scope to fold the optical path as in Fig 1B (left) is to be designed, with the mirrors at 4 and 9 inches from the tube face. Find the di- mensions of the reflective surfaces and their offset distances for mounting purposes.
First Method:
The diameter of the aperture of an F’/2.3 lens is equal to that of the front lens element when it is wide open. Consequently, the radius is
Maximum diameter ns
PL = o (7) - Focal length 2 (F-number of lens)
35
L= 5 @3) = 7.6mm = 0.3 in.
Then Eqs (i) and (2) lead to
(12.2) (2.3)
L _ 9 = 14 in.
os 14
(right) and Fig 2,
@ = tan" = 9.3 deg
from Fig 1
a ) [ee
The two values of L, (which is the distance from the apex of the cone to the reflector measured along the optical axis, are 10 and 5 inches. The corresponding mirrors have the design values:
= 0.167; i = 0.040.
a, = 2.40 in.; bh) = 1.67 in.; x2.. = 0.40 in.; a. = 1.20 in.; be = 0.84 in.; r,.2 = 0.20 in. The essential periscope dimen- sions are drawn to scale in Fig 3. The physical structure often is much larger than the bounding cone near the camera in order to retain good mechanical strength. When this is the case, light baffles with inner radii only slightly larger than this cone should be inserted in order to reduce the stray light. The periscope reflectors should not be much larger than the minimum dimensions. Second Method:
After computing p, by means of Eq (7), the tube face and outer lens element are drawn to scale with the known distance between them, as in Fig 4A. The triangle determined by these two line segments is then completed, and lines at 45 deg are inserted at the reflector positions on the optical axis, as in Fig 4B. This figure represents a cross section of the light cone before the reflectors are actually inserted to fold the light path. Consequently, the major axes of the ellipses and the offset distances can be measured directly on the scale drawing. The minor axes are found from the axial ratio of Fig 1 (right), which shows that for a = 9.3 deg,
a
lies 1.434 Alternatively, the minor axes may be found by rearranging Eq (6):
- ms 1/2 b [ * | - 0.8409 V x. L, v2
The results, of course, are iden- tical to those of the first method. In general, the second method is faster and slightly more accurate when the drawing scale is large.
electronics
NEWEST
in the most extensive line in the industry
CENTRALAB
CERAMIC
TRIMMER CAPACITORS
THAT MEET
MILC-81A
825 SERIES ACTUAL SIZE
Rated at 600 VDCW, 1500 VDCT, these units are well within MIL specifications for change in capacity under temperature and vibration extremes. Available in NPO, N300, N500 and N650 tem- perature coefficients in all standard capacity ranges.
TEMPERATURE CHARACTERISTIC
CAPACITANCE RANGE (MMF)
CRL
MIL LETTER
MIL CRL |NUMBER'
NPO
A
070
N300
120
N500
130
B Cc D
200 250 300
450
MICRO-MINIATURE ACTUAL SIZE
Rated at 100 VDCW, 250 VDCT, this unit measures only 0.201” in diameter and can be supplied on a ceramic base plate, to your specifications, as small as 0.25” square, plus leads or mounting. It is available in the following ranges: 1.5 to 5 mmf, 3 to 10 mmf,
and 7.5 to 25 mmf.
For detailed information on these and many other trimmer and special ceramic capacitors, write for Engineering
Bulletin Group ‘‘C."’
D-6118
THE ELECTRONICS DIVISION OF GLOBE-UNION INC. 914M E. KEEFE AVENUE + MILWAUKEE 1, WISCONSIN in Canada: Centralab Canada Ltd., P.O. Box 400, Ajax, Ontario
ELECTRONIC SWITCHES « VARIABLE RESISTORS « CERAMIC CAPACITORS « PACKAGED ELECTRONIC CIRCUITS ¢ ENGINEERED CERAMICS
December 29,
1961
CIRCLE 53 ON READER SERVICE CARD 53
RESEARCH AND DEVELOPMENT
Powerful Vhf Radar Probes Sun’s Corona
Half megawatt radar and 1,024-dipole antenna array are gathering data
about solar phenomena
LONG-TERM STUDY of radar echoes from the sun is providing valuable scientific information. The continu- ing systematic experiments could improve prediction of solar activity to avoid interruptions to radio com- munications and reduce hazards to space exploration.
The detailed study covers 32 radar measurements made during an eleven-week period from April 19 to July 7 near El Campo, Tex. Lincoln Laboratory of MIT is con- ducting the project with joint U.S. Army, Navy and Air Force support. Although the first radar contacts with the sun were made by Stan- ford in April 1959, these are the first regular measurements over an extended period.
Scientific Data Provided
Radar studies provide valuable information about the _ corona, which ejects huge showers of high- energy particles during sunspot ac- tivity. The particles cause interrup- tions of communications and present one of the most serious hazards to space travel. With radio and optical techniques, radar can
54
improve warning of these out- bursts, measure their location and intensity and possibly predict them. One indication of the tests is that the sun is 50 to 100 times less capa- ble of reflecting radio waves than reported by Stanford. However re- flectivity increased up to 50 times in later individual tests when solar activity was much more _ pro- nounced. Also these measurements are being made at 38.25 Mc, while those of Stanford were made at 26 Mc where reflectivity may be greater. These differences indicate the wide variations in solar phe- nomena associated with radar re- flections and the valuable informa- tion that radar can provide. Thickness of the _ irregularly shaped corona as observed by radar is comparable to the visible ball of the sun, called the photosphere. Re- flection (radar cross section) de- pends on size of the reflecting ob- ject and its reflecting efficiency. Although apparent diameter of the corona at these frequencies exceeds 1.5 million miles, average cross sec- tion in the experiments appears to be only a few hundredths the size
of the photosphere. This low reflec- tivity indicates the extent that radio waves penetrating into the corona are absorbed.
Measured cross section at this frequency is substantially less than had been calculated from theoretical models, which are based on assump- tions made without detailed infor- mation. One assumption is that elec- tron temperature in the corona is about 1 million degrees C. If tem- perature were assumed to be one- half million degrees, theoretical cross section for a quiet sun would be much closer to that measured.
Effective size and shape of the corona and its changing reflectivity with sunspot activity can be studied systematically with radar. Present observations of a quiet sun indicate that radar echoes were obtained up to a half million miles from the photosphere. The great fluctuations in effective size, shape and intensity of the corona expected because of violent solar activity have already been observed. Long-term radar ob- servations will yield quantitative data about these phenomena.
Radar Penetrates Corona
Radar reflections frtm the sun are unlike those reflected from solid objects that permit precise range measurements. Signals penetrate the gases of the corona distributing reflections over the depth. This phe- nomenon combined with the turbu- lence and irregular shape produce complex radar returns that enable radar studies to obtain data about the nature and extent of electrical phenomena and disturbances.
Violent activity associated with sunspots causes large clouds of high-energy particles to be ejected from the corona that interact with the ionosphere and disrupt radio communications. The effect occurs about 18 hours after the solar ac- tivity has been detected. These clouds, which are a menace to space flight, are sometimes sufficiently in- tense to damage or destroy elec- tronic instruments in space probes. Systematic radar observations can
electronics
REGULATED
BEST 0-30v dc/0-300 ma—$119.00 0-40v de/0-500 ma— $159.00 INVESTMENT IN
POWER SUPPLIES
0-30v de/0-300 ma— $99.00 REAR VIEW FOR ALL MODELS
ca | a fey | FEE Kol! |. Lael = Te TE fee ==, | oo 5S 9 SH Oo —"
“a o ea5.000
sn@me £0)8) BENCH
ed DIMENSIONS
MODEL VOLTS ; CURRENT uw Fw) Oo | PRICE ABC 30-0.3 | 0-30 | 0-300ma. | 4%” | ax | 556” | $ 99.00
ABC 40-0.5 | 0-40 | 0-500ma. | 4%” | 8%” | 956” | $139.00
Dood ~ _ ‘| 950” | $139.00 ABC 75-2 | 0-7.5 | 0-2amp | 4%” | 8%” | 9%” | $139.00 ABC 15-1 | 0-15 | O-1amp | 4%” | 8%” | 9%” | $139.00
For meter: add suffix “M” to Model No. and $20.00 to price. Rack Adapter: Model RA-4 (for 2 units), RA-5 (for 1 unit) available at $15.00 each.
0.05% Line/Load Regulation @ Control Amplifier Terminals and Stability included for:
0.5 mv (rms) Ripple Remote Constant Voltage
Programming Adjustable Overload Protection Remote Constant Current (Front Panel)
Programming Input 105-125v ac, 50-440 cps Remote Error Sensing Low Price is achieved by high Complementary Tracking — volume production without Voltage Compliance Extension
sacrifice in quality and Series or Parallel Slave reliability. Connections
December 29, 1961 CIRCLE 55 ON READER SERVICE CARD 55
simple, low-cost way to increase equipment
Patented
ie ; t-dis: ipating Electronic Tube
ge
= | A obits 5
ee replacement costs due to t way to meet your MTBF reliability contract requirements is to start with the tubes — it costs so little to make them ‘“‘TR safe’’!
_
WRITE TODAY FOR IERC TR TECH BULLETIN NO. 1121.
IERCES.ovisicw,
international Electronic Research Corporation 135 West Magnolia Boulevard, Burbank, California
Foreign Manufacturers: Europelec, Paris, France. Garrard Mfg. & Eng. Co., Ltd., Swincion, England
56 CIRCLE 56 ON READER SERVICE CARD
be a valuable supplement to radio and optical methods for studying the nature, scale and frequency of these disturbances.
The radar transmitter provides 0.5 megawatt continuous output. It feeds an array of 1,024 dipoles in 8 rows 15 feet apart and about 4 mile long. The fan-shaped beam is 15 de- grees in the east-west direction and } degree in the north-south direc- tion. It is aimed by adjustment of the individual dipoles.
Since the photosphere subtends an angle of about 0.5 degree viewed from the earth, beam thickness per- mits observation of the photosphere and the surrounding corona. The sun travels from east to west along the 15-degree beam width in a little over a half hour, which is the time for a complete radar run. The radar transmits continuously for 16 min- utes, which is the round-trip time of sun-reflected signals. After 16 min- utes when signals begin to return, the transmitter is switched off and the receiver on for 16 minutes.
The 38.25-Mc transmitting fre- quency is switched up or down 8 Ke every 8 seconds to distinguish echoes from cosmic and sun-gener- ated noise.
Circuit Permits Accurate Voltage Ratio Measurement By P. A. LENK,
Reactor Control Labs, General Dynamics/Electronics, Rochester, N. Y
ACCURATE measurement of the ratio of two voltages is provided by a simple circuit using readily avail- able parts. Its resolution is better than 0.1 percent.
The ratio of two voltages must often be measured accurately. For example, it may be necessary to measure an output voltage as a function of a maximum level or to determine linearity in terms of the ratio of input to output voltage.
The circuit in the figure was de- veloped specifically to measure the ratio of two in-phase a-c voltages of about 80 volts rms to within 0.1 percent. Potentiometer R, is a ten- turn potentiometer with a ten-turn dial. The diode provides the indica- tion of the ratio between the un- known voltage and a reference volt- age. In this case, a value of 5,000
electronics
UNKNOWN VOLTAGE
Voltmeter becomes accurate null de- tector when difference voltage is less than one half volt
ohms was suitable for R,.
A 115-volt, 6-watt incandescent lamp limits voltage applied to the voltmeter when the difference be- tween the unknown and reference voltages exceeds 0.5 volt. Both R, and the lamp must be selected for the particular application, includ- ing the maximum power they will be required to dissipate.
The value of R, is chosen so that a full-scale deflection is obtained on the meter when the difference be- tween the two voltages is maximum. Thus if the reference voltage were zero, full-scale meter voltage would be equal to the maximum value of the unknown voltage.
Circuit Operating Principles
In operation, diodes D, and D conduct when the difference be- tween the unknown and reference voltages exceeds 0.5 volt, and the meter is shunted by R,. Also, high voltage difference heats the lamp, which further reduces the voltage applied to the meter. The two volt- ages are balanced by rotating the potentiometer in a direction that reduces the meter deflection.
When the difference between the unknown and reference voltages is less than 0.5 volt, the resistance of the lamp becomes negligible and the two diodes do not conduct. The dif- ference voltage is now applied to the meter with no appreciable se- ries or shunt impedance so that the 3-volt meter becomes a _ sensitive null detector. At null, the ratio of the two voltages is indicated on the dial of the potentiometer.
The circuit has proved to be use- ful, particularly since it can be as- sembled from parts readily avail- able in most laboratories. Accuracy has not yet been fully determined. Resolution is better than 0.1 per- cent, which is the smallest incre- ment of adjustment provided on the potentiometer.
December 29, 1961
GUARANTEE of Quality This GUDEBROD Lacing Tape is Manufactured under strict Quality Control. Complete test data is on file for your protection under Lot #18861
THIS SEAL GUARANTEES YOU REAL LACING ECONOMY oo.
increased production
with fewer rejects ! Ts LE
Always specify Gudebrod whether you use one spool of lacing tape or thousands because Gudebrod lacing tape is produced under strict quality control. Gudebrod checks and rechecks every lot of tape to insure that it meets the highest standards . .. higher standards than those required to meet MIL-T specifications.
Gudebrod helps increase your production because we carefully test, measure and maintain close tolerances on such characteristics as slip resistance, fray resistance, breaking strength, wax content, fungistatic effectiveness. These and other tests assure you that when Gudebrod lacing tape is used production increases. Knots don’t slip . . . harnesses stay tied . . . assemblies remain firm . . . there are fewer rejects!
Whatever your lacing needs—Teflon*, dacron{, glass, nylon, high temperatures, special finishes—Gudebrod makes it or will produce a tape to meet your special re- quirements. If you want a tape to meet 1500°F . . . Gudebrod Experimental Research Project 173 is the answer. If you want a tape that meets MIL-T-713A . . . Gudelace® (Style 18 Natural) is the answer.
MAKE THE H-R TEST! Write for samples of Gudelace or other Gudebrod lacing tapes and have them tested in your harness room. Compare a harness tied with a “Quality Controlled” Gudebrod tape and any other tape. This test will convince you that when you specify Gudebrod you specify real economy—increased production with fewer rejects.
Write for our free Technical Products Data Book. It ex-
plains Gudelace and other Gudebrod lacing tapes in detail.
*Dupont’s TFE fluorocarbon fiber. tDupont’s polyester fiber.
GUDEBROD BROS. SILK CO., INC.
Electronics Division Executive Offices
225 West 34th Street 12 South 12th Street New York 1, New York Philadelphia 7, Pa.
CIRCLE 57 ON READER SERVICE CARD 57
COMPONENTS AND MATERIALS
Devices Featured At Japanese Forum
By CHARLES L. COHEN,
McGraw-Hill World News
TOoKYO—Interest here in small de- vices—crystal resonators, capaci- tors, resistors, photocells, magnetic materials, varactor diodes, and in- dicators for transistor circuits— was evidenced by more than 1,000 Japanese engineers who showed up to spot useful components for cir- cuit design at the recent three-day meeting of the Japanese Institute of Electrical Communications En- .gineers. Crystal Resonator Wafers
At one of these sessions, Atsushi Tachibana of Hibachi described the construction of quartz crystal resonators on 8 mm sq AI.O. micro- module wafers. Space occupied by the terminals leaves only 6 mm sq space available for mounting crys- tal. Total height from bottom of wafer to top of metal crystal cover
is only 2 mm. Crystal resonators measure 4.3 x 4.3 mm, resonance frequency is 45 Mc, resonance re- sistance is 20 to 40 ohms.
Another small component seen was the silicon oxide dielectric ca- pacitor, developed by Tsuyoshi Matsunaga of Nippon Electrical Co. The dielectric of this device is Si,O., rather than SiO and SiO, previously reported in Japan.
To construct this capacitor, an aluminum electrode is first evapo- rated on 10-mm-sq glass substrate in vacuum. Si.O, is evaporated at a pressure of 1 10° mm mercury, and then a second aluminum elec- trode is evaporated. Entire capaci- tor is baked after lead connections are made with silver paste.
Area of dielectric between elec- trodes is 0.25 sq cm, capacitance is 250 pf. Insulation resistance at 20 v d-c is greater than 2 10° meg- ohms, tan 6 at 1 Kc is better than
Heat Blanket for Accelerometers
A MOLDABLE, uncured silicone rub- ber and glass fabric with an alu- minum one side is helping to solve heat applications problems in several missile com- ponents at Thermal Systems, Inc, formerly Electro-Flex Corp., Gar- dena, Calif.
In an application on the Minute- man missile, a heater made from the silicone based material, Irving- ton brand SRGA fabric 0208, ( Min- nesota Mining and Manufacturing Co.), is used to maintain a constant temperature inside a black box in the autonetics system.
By using SRGA fabric to control environment for two accelerometers inside the box, designers of the heating assembly were able to hold down the weight of the heat blan- ket, reduce the wattage require- ments, conserving the limited power available in the missile, and reduce the insulation necessary to stabilize temperatures within the box.
coating on
Typical shapes of heaters for mis- sile electronic components made by Thermal Systems, Inc.
These fabrics are made of spe- cially woven and treated glass base cloth, coated with silicone rubber and a micro-thin facing of vapor coated aluminum which imparts a closely knit surface of highly-re- flective particles. Fabrics retain flexibility, drape and heat resist- ance characteristic of silicon rub- ber-coated cloths.
5 x 10“. Temperature coefficient between —40 and 85 C is 50 x 10° per deg C, capacitance change due to temperature cycling is less than 0.02 per cent. However at fre- quencies above 1 Mc capacitance increases slightly.
Resistors and Thermistors
Tadtsugi Ito, of Waseda Uni- versity, explained the theory of a potentiometer with no sliding con- tact. The gap between the parallel or concentric resistance element and the metal pickup element is bridged with CdS. Point of contact is moved by changing the position of a beam of light. Problems still remaining to be solved for practical use are reduction of the resistance of the CdS, which is too high for low-resistance potentiometers, and lowering of the CdS lifetime for fast response.
Precise reproducible thermistors were fabricated by Tomojiro Asaba, of Tokyo Institute of Tech- nology, from 35 to 45 ohm-cm ger- manium. Chemical etching after fabrication allows precise resist-
_ ance values to be obtained.
Also small are the silicon photo- voltaic cells for card reading in electronic computers, introduced by Hiroyuki Nishimi of Fuji Com- munications Apparatus Co. Major advantage of units in pilot produc- tion, which consist of two rows of nine cells each on the same silicon wafer, is ability to self-check. One row is used for reading, while the second row is used for checking.
Construction is similar to solar batteries. Boron is diffused into a 25 mm diameter wafer of 0.1 to 1 ohms silicon; then grooves are etched to separate individual func- tional devices on same wafer. Cells on wafer may be in rows, or in mul- tiple rows. Negative electrode is common, leads are attached to in- dividual positive electrodes. Effec- tive area of devices built to date is 1 to 25 sq cm.
Other advantages include small size, self-generating voltage which eliminates the need for bias sup-
electronics
“electronics
READER SERVICE
Use these handy prepaid READER SERVICE POST CARDS for more detailed information on: PRODUCTS ADVERTISED, NEW PRODUCTS “On the Market”, LITERATURE of the WEEK
CHECK COUPON FOR FREE REPRINT of the MONTH
“Logarithmic Transmission Line Charts,"’ by H. F. Mathis
S t mn be used t Otain straignt-iine O py per pers nly, if more are required » a
t ber the READER SERVICE post card at the right that corresponds to the
+ } + +} ss ~ fA - ore ea . a De Sane —— . - , ill f \A ber e bot Advertisement, New oduct item, or the Literature of the Week
re interested
F r All writter r be legible in order to be efficiently pro-
ALL FOREIGN INQUIRIES that cannot reach electronics before the expiration dates noted t meager Service f[ t ra t be mailed directly to the manufacturer. The manufacturer
ties for responding t juiries. electronics merely provides and clears
TO SUBSCRIBE TO OR TO RENEW electronics n the ‘‘For Subscriptions’’ area on the ard if esire t bscribe to or renew your present subscription to electronics. Send no electronics wil! | you at the addre ndicated on the Reader Service post card
MULTI-PRODUCT ADVERTISEMENTS — For informatior pecific items in multi-product
. - . ash } P storoctor ) precise pr ict in W yOu are interested.
ervice Department offers 4 types of reprints for sale: 1 Reprints of Special
with definite costs for varying quantities: 2 Reprints of Special Re
rts that ve appeared in past issues; 3 Reprints of other editorial material in the current minis rder 100); and 4 Reprints of editorial that has appeared in past issues
On other than Special Reports we cannot publish prices because the ing upon the length of the article
t t j arge oSstage, etc. bring the costs for Special Reports to: ent ra single reprint: 60 cents « for 11 to 24 copies; 50 cents each for 25 or more
electronics editorial article ever printed see
For tearsheets or single photocopies
erse side of tt
For list of Reprints of past Special Reports available see reverse side of this page.
——-
Name Title Company
Address
VER (901
CHECK HERE FOR FREE REPRINT of the MONTH
Oceans
————_— —_— EE a <—— ome
CHECK HERE FOR FREE | REPRINT MONTH
of the
* Medical Ele« Part Vi
tronics
R-19f
t SPECIAL REPORTS FEATURE ARTICLES f
n this issue, f tled nm page(s
past issues, fi!
Name . . _ Number and Street___ . —_ ” _
City, Zone Ne., State
TT Seercniiagne Section
DEC. 29, 1961 Card Expires
FEB. 28, 1962 For Foreign Mailings
MARCH 14, 1962
FOR SUBSCRIPTIONS
WU €
DOMESTIC
veal
CANADA FOREIGN
——Searchiight Section
DEC. 29, 1961
Card Expires FEB. 28, 1962
For Foreign Mailings
MARCH 14, 1962
DOMESTIC
."
CANADA FOREIGN
Product(s
+
REPRINT ORDER FORM
FOR SUBSCRIPTIONS
Observing Life Processes (I
DOMESTIC
mum order 10C opies
CANADA
FOREIGN
FIRST CLASS PERMIT NO. 64 NEW YORK, N. Y.
|
oO PX
te (
BUSINESS REPLY MAIL
ISTAGE STAMP NECESSARY IF MAILED IN THE UNITED STATES
6¢ Postage Will Be Paid By electronics
Reader Service Dept.
Box 611
Ridgefield, Conn.
FIRST CLASS PERMIT NO. 64 NEW YORK, N. Y.
|
|
NO P<
“iictal ie aA ia he a
BUSINESS REPLY MAIL Se MeCN
STAGE STAMP NECESSARY IF MAILED IN THE UNITED STATES Ge ee
OR, CU ES
6¢ Postage Will Be Paid By Ra RE
electronics een
Reader Service Dept. paces Box 611
Ridgefield, Conn. ne
| TOUR ey Pare
(5 SC ERAS
OTS IR:
ad
SE SS
ERS,
FIRST CLASS
PERMIT NO. 64 NEW YORK, N. Y.
0 PO
BUSINESS REPLY MAIL
TAGE STAMP NECESSARY IF MAILED IN THE UNITED STATES
6¢ Postage Will Be Paid By
electronics
Reprint Service Dept. 330 West 42nd Street New York 36, N. Y.
All electronics Editorial Matter
Can Be Made Available in Reprint Form
FOR SINGLE REPRINTS: electronics offers reprint r photo
rinte
} er le ' oril teq T ¢ e fr , — . v fora ’ [ var ; " r r r r T r Tr ?r Ke eT ri r { +} y t electronics Nest 42nd St.. New Y - ¢ r) ¢ Lt x 14 T T re rint Reprints Available on Past a by . . ~ Special Reports and Feature Articles (Order by Key No. Use REPRINT ORDER FORM on Reverse Side.) KEY NO TITLE OF REPRINT NO. OF PAGES SSUE R-5 Electronic Markets Special Report 3 R-7 Electronics Research and Development Around the World R-17 1960-61 electronics Buyers’ Guide Reference Section 64 Medical Electronics— R-19a Part |: Diagnostic Measurements R-19b Part Il: Diagnostic Systems and Visualization € R-19¢ Part Ill: Therapeutic Devices R-19d Part IV: Prosthetics—Hearing Aids and Blind Guidance Devices R-19¢ Part V: Prosthetics—Substitute Organs and Limbs R-19f Part VI: Observing Life Processes R-21 Electronics in Europe Plasma Engineering R-22a Part |: Generating and Heating F ma R-22b Part Il: Measuring Parameters R-22 Part Ill: Practical Applications of Plasma R-23 What's New In Semiconductors R.24 Reference Section 1961-62 electronics Buyers’ Guide R-25 1961-62 electronics Buyers’ Guide Product Listings Manufacturers Index Lasers: Devices & Systems R-26a tart Principles of Functioning a ser Mate R-26t Part I!: Communications, Navigati« Rang and Undersea Applicat 1s R-26¢ Part lil: Military and Computer Appi Frequency Tuning, Modula n, Demodula Mixing Techniques R-26d Part IV: Scientific and Medical Apr t aser Optics Commercial! Equipment : . 5 R-27 Missile And Space Electronics ) e ¢ € ¢ ea f ¢ ea
a . ft
plies, fast response, spectral char- acteristics similar to the human eye, insensitivity to temperature changes, and long life. Output cur- rent is approximately 50 »A/mm* for light source of 3,200 K, 10,000 lux; under these conditions output voltage is approximately 0.45 volts.
Also for computers is a method of using commercially available 1.2 mm ferrite cores in memories which feature non-destructive read- ing. This development, reported by Hiroji Ihara of Nippon Electric Co., makes use of reset, writing and symmetrical reading pulses.
Yukio Fukukawa, of Fuji Com- munication Apparatus Co., intro- duced a small three-electrode neon bulb indicator which operates with a small voltage change on its con- trol element. This tube is espe- cially useful as an indicator in transistorized computers and counters. Concept applied is remi- niscent of the Philips decade indi- cator (see ELECTRONICS, Nov. 3, p 60).
Varactor Diode Application
Akio Sasaki, of Kobe Kogyo, de- veloped a new method of controlling the frequency of reflex klystrons. The change of capacity of reversed biased varactor diodes was used to change the resonant frequency. Microwave Associate’s MA 4600 diodes were used in this experi- ment. With the diodes located in the cavity outside of the evacuated portion of the 7V204 reflex klys- tron, approximately 2.5 to 10 Me variation could be obtained at 7,000 Me.
It would be desirable to vary both repeller and diode voltage simultaneously to realize the fol- lowing conditions; ductance G, ance G
electron con-
plus circuit conduct- equal zero. Electric susceptance B. plus circuit suscept- ance B.. equal zero. Then output fre- quency could be varied over a rela- tively wide frequency band with almost constant power output. This would enable FM signals with small AM component and low differential modulation distortion to be ob- tained.
Several means of eliminating in- terference to X-band radar from rain and snow were explained by Noriomi Ochiai, of Tokyo Keiki Seizocho KK, in the symposium on
December 29, 1961
Aeronautical and Marine Radar. Cireularly polarized radiations were used. The metal grid circular- izer was developed for marine radars, which customarily use horn-fed reflector antennas. Ochiai showed a comparison of ppi radar patterns made using horizontal polarization and those made using circular polarization. A buoy clearly visible through heavy rain when using circular polarization was completely masked when using horizontal polarization.
Indium Antimonide Used As Voltage Regulator Element
OUTPUT VOLTAGE of this magneto- resistance voltage regulator is kept constant by an indium-antimonide semiconductor, measuring } by } by 0.004 inch, whose resistance varies in proportion to the strength of an applied field.
Designed specifically as a supply source for a tunnel diode, this de- vice is one of the first practical units to use the phenomenon of magnetoresistance. An increase in input produces a stronger field in the electromagnet (coiled wire in the photo), thereby increasing the resistance of the indium-antimonide element.
The regulator can maintain a 0.15-volt output within +5 per cent at 0.1 amp, even when load resist- ance changes 50 per cent with a simultaneous 10 per cent change in input voltage, which is normally 1.5 volts. Much more precise regu- lation than this can be achieved when magnetoresistance is used in regulators with outputs of one volt or more.
The regulator was developed by 3attelle Memorial Institute, Colum- bus, Ohio, as part of a program to determine the feasibility of em- ploying indium-antimonide in elec- tronic devices.
newest, simplest way to measure r-f power...
PRD 680 calorimetric power meter!
., With this new instrument you can measure power accurately
and directly, from a few micro- watts up to a half watt. No bolometers, barretters, thermistors, or external atten- uators are necessary. Nine power ranges can be selected on the front panel dial, and direct power reading in DB or watts can be made in seconds. Instrumentation is accurate to 2%. A lightweight (20 lbs.) , easily portable unit, the PRD 680 utilizes the PRD series of dry calori- meters which plug into the front panel interchangeably. Shown here is the N680, covering the range of 0 to 10 kme/sec. Waveguide plug-in units for X and K bands will be available soon.
Send for data!
PRD ELECTRONICS, INC.
202 Tillary St., Brooklyn 1, New York ULster 2-6800
1608 Centinela Ave., Inglewood. Calif. ORegon 8-9048 , A Subsidiary of
Harris-Intertype Corporation overs
HARRIS
INTERTYPE . onsen
CIRCLE 61 ON READER SERVICE CARD 61
PRODUCTION TECHNIQUES
Clock Motor
Speeds Servo Motor Tests
By THOMAS POTTS Servo Dynamics Corp. Somersworth, N. H.
MANY SERVO MOTORS in use today have never met the starting voltage requirement they were designed and tested for, due to the inade- quacy of the methods and test pro- cedures used to measure starting voltage. Over the past few years many different methods of measur- ing the starting voltage of a servo motor have been tried," * * * *° but all give values that are inconsistent and unrepeatable; usually the test must be repeated several times and the poorest result used as the best approximation. Even after tests have been run many times, it is still possible that the poorest value for a particular unit has not been found’.
Plots of starting voltage versus the initial position of the shaft may, under some conditions on some units, vary as much as five to one. In addition, clockwise and counter- clockwise tests (Fig. 1) shows that
Servo
62
motor test set-up showing special fixture for motor and related measuring equipment
ROTOR POSITION O
IN DEGREES
FIG. 1—Plots of starting voltage for cw and cew rotation. Rotor slots create localized effects where starting voltage essentially goes to zero
variations in maximum and mini- mum values 77 starting voltage are not necessarily the same for both directions of rotation. This is caused by magnetic and electrical anomalies, not bearing friction as is generally supposed.
To insure that a servo motor will always start in a system at rated starting voltage, the testing method should meet several requirements:
it should be practical for production testing, find all the points of high starting voltage for both directions of rotation, be easily and quickly accomplished with a minimum of extra equipment, and be repeatable from day to day and be independent of test operator judgment.
In actual system use, servo mo- tors are almost never run no-load. In most systems either a tachom-
FIXED p— PHASE VOLTAGE
RE- VERSIBLE Sw
SPEC. STARTING
COUPLING SWITCH VOLTAGE
FIG. 2—Clock motor is enough load on the servo motor to stop it if starting torque is below specs
electronics
R7NC “HEAVY DUTY”
BY-PASS DISCAPS,
SPECIFICATIONS POWER FACTOR: 1.5% Max. @ 1 KC weer: Type B DISCAPS meet or exceed all EIA POWER FACTOR: 2.5% Max. @ 1 KC RS-198 specifications for Z5U ceramic capaci- (after humidity) 7 , tors. Designed for by-passing, coupling, or WORKING VOLTAGE: 1000 V.D.C. filtering applications, Type B DISCAPS are TEST VOLTAGE (FLASH): 2000 V.D.C. manufactured in capacities between .00015 and .04 MFD. A heavy ceramic dielectric element provides INSULATION: Durez phenolic—vacuum a safety factor where steady or intermittent waxed high voltages occur. Type B DISCAPS show a INITIAL LEAKAGE RESISTANCE: Guoran- minimum capacity charge between +10°C and teed higher than 7500 megohms +85°C (see curve). AFTER HUMIDITY LEAKAGE RESISTANCE:
Guaranteed higher than 1000 meg- ohms
LEADS: No. 22 tinned copper (.026 dia.)
TYPICAL = CAPACITY VS. TEMPERATURE TYPE-B-DISCAPS 25° TO 85°C
25°C VALUE
PERCENT CHANGE
FROM
TEMPERATURE °C
DISCAP RADIO MATERIALS COMPANY
CERAMIC A DIVISION OF P. R. MALLORY & CO., INC. CAPACITORS \ GENERAL OFFICE: 4242 W. Bryn Mawr Ave., Chicago 46, III. >, Two RMC Plants Devoted Exclusively te Ceramic Capacitors
= weil
CIRCLE 63 ON READER SERVICE CARD 63
December 29,
MAKING ROOM AT THE TOP
omaeeamreeonererman tea Nt SOARES “OR hs ane SNARES REGRET MORBONRE HERETO
4 S F > teetbeod,,, e .** eehere -. —— oe us "bore,
x oe
See the 41 additional EICO instruments help- ful for your lab and line work. Write for free catalog and name of neighborhood distributor,
@ Dept. E-12¢ 3300 N. Bivd., L.1.C. 1, N.Y. cpg Export Dept.: Roburn Agencies, Inc. 431 Greenwich St., N. Y. 13, N.Y.
Add 5% in the West.
EICO creates a new, professional lab quality test instrument series
at moderate prices.
AC VTVM & AMPLIFIER
#250 Kit $49.95, Wired $79.95
VTVM: 12 ranges from imv to 300v
response absolutely flat from 10 cps to 600 kc; input impedance 10M shunted by 15uyzf; accuracy +3% of full scale.
Note: Average responding meter calibrated in rms. Linear 0-1, 0-3 scales. Decibel scales based on Odb=1mw in 600{2 with 10db in- terval between ranges.
AMPLIFIER: 60db gain on Imv range; response +0, —3db from 8cps to 800kc; output to 5V rms undistorted, variable down to zero by attenuator contro! at output; input impedance 10M22, output impedance 5K2; hum : noise —40db for signal inputs above mv.
DESIGN QUALITY: All frame-grid tubes; 60db frequency-compensated input attenuator ahead of cathode follower with 10db/step attenuator following; two-stage R-C coupled am- plifier and full-bridge meter circuit in one overall feedback loop; no response adjustment required in amplifier cir- cuit; single sensitivity adjustment; voitage-regulated power supply. 50/60 cycle operation.
EICO MODEL 255 AC VTVM identical to Model 250 described above, but less amplifier facility. 50/60 cycle operation.
Kit $44.95 Wired $72.95
64
CIRCLE 201 ON READER SERVICE CARD
The high standards of MITSUMI electronic
components are insured by a fully-auto- mated assembly system, and double-checked by rigid quality controls. Mitsumi Electric Company is Japan's largest manufacturer of components for radio, television and
communicetions equipment.
Good parts work best!
Intermediate Frequency Transformer \FT
MITSUMI PARTS
MITSUMI ELECTRIC CO., LTD.
Komae, Kitatama, Tokyo
CIRCLE 64 ON READER SERVICE CARD
POLYVARICON Variable Copacitor
eter, synchro, gear train, indicator, etc., presents some small load to the motor. Further, tests indicate that under conditions of a small load, the variations in maximum and mini- mum starting voltages increases. Thus there are larger discrepancies in the characteristics of a motor in a system than are predictable from normal methods of measuring start- ing voltage. To meet all of the above requirements, Servo Dynam- ics Corp. developed a method for testing each motor for all positions of the rotor in both directions of ro- tation, under conditions of a very light load. This test, shown in Fig. 2, is simple, quick, eliminates oper- ator judgment, and gives repeat- able results in production.
The reversible drive motor is a low speed clock motor connected to run so that the drive half of the
As long as the two halves of the coupling remain in contact, servo motor meets starting voltage specs
coupling linkage moves in the same direction as the motor under test. Thus the linkage acts as a brake or load on the motor being tested. Dur- ing the test the servo motor is ener- gized with normal fixed phase volt- age and with specified maximum starting voltage on the control phase. The reversible drive motor is then run and the operator ob- serves whether or not the two halves of the coupling linkage re- main touching at all times during one complete rotation of the motor output shaft. The phase of the con- trol voltage is then reversed and the drive motor is reversed. The test is then re-run, again observing whether or not the two halves of the coupling linkage remain touching for one revolution. If the servo motor stops, allowing the two halves of the coupling linkage to separate, then the starting voltage of the servo motor exceeds the specified maximum. The test has bee: vua'-
electronics
uable for production testing since it is a uniform and reproducible method that is wholly determined by the motor itself and is independ- ent of the skill or judgment of the test operator.
To find the actual maximum or minimum starting voltage of a mo- tor, the voltage on the control phase can be adjusted until the motor under test just rotates for both di- rections of test without permitting the linkage halves to separate. To eliminate marginal units, all motors can be tested at 95 percent of speci- fied starting voltage.
REFERENCES
(1) ARP-497, “Aeronautical Recom- mended Practice-Precision Control Mo-
ors”, SAE.
4 ARP-667, “Aeronautical Recom- Practice- Pre ‘ision Motor Tach- eter Generator’, SAE MIL-S- 17087, “Servo Motors-2 Phase, 400 Cycle”
(4) MIL-S-17 806, (NOrd), “Servo Mo- tor-T ache ymeter Generator, 2 Phase, 400 Cycle’
(5) MIL-S-22432 (WEP), “Servo Mo- tors-General Specification”.
(6) Bureau of Naval Weapons, “Study of Standardization of Servo Motor and Tachometer Generator Acceptance Test Equipment,” June 1960. Contract N164- 8637 of Lockheed Electronics.
Silicon Rectifiers Directly Soldered
A DIRECT soldering technique has been developed for manufacturing silicon power rectifiers. The method uses a diffused silicon junction to which copper disks are soldered; molybdenum or tungsten washers are not required. Cells with current ratings to 400 amps, and with peak inverse voltage ratings from 1,000 to 1,200, can be produced.
The technique is based on the stress, strain and thermal expan- sion characteristics of silicon and copper. Calculations show, and ex- periments confirm, that if ¢./D is approximately 0.2 or _ greater (where t. is the thickness of the copper electrodes and D the diam- eter), and if t,/D is approximately 0.02 or less (where t¢, is the thick- ness of the silicon disk and D its diameter), thermal stresses will not be strong enough to cause rectifier failure during normal operatio.. The two copper disks are the same diameter as the silicon disk and are the outer layers of the rectifier sandwich.
Otomi Fujii describes the process in the Summer 1961 issue of Toshiba Review.
December 29, 1961
JUST WHAT THE DOCTOR ORDERED
7 regen
LOW NOISE FIGURE
12 MILLIAMPERE POWER DRAIN flashlight
SMALL SIZE— Lisi WEIGHT 21" x a
THE NEMS- CLARKE
‘SOLID STATE TELEMETRY PREAMPLIFIER
| SOLID STATE PREAMPLIFIER |
a
Here’s your baby for outstanding performance and economy in the 225-260 megacycle telemetry range —the Nems Clarke SSP-101 completely solid state preamplifier. Featuring extremely low noise, flat response, and a hefty 25db minimum gain, it’s at home in any environment... installed either in the antenna mount or the coax cable. Its own external 12 volt power supply is available for rack mounting. Baby sitting? Forget it! The SSP-101 operates for thousands of trouble free hours at unattended locations.
Write for Data Sheet 999
ee
PRODUCERS OF NEMS-CLAREE EQUIPMENT
| 919 JESUP-BLAIR DRIVE, SILVER SPRING, MARYLAND / 2301 PONTIUS AVENUE, LOS