I c

I ‘ I I 1 I I I 8 I 1 I E 1 I I I I I

THIN-FIIM PERSONAL COMMUNICATIONS

1 AND !lEUmlTR.Y SYSTEM g.FPcTs)

For the period -3 of eptember 24, 1966 t o December 24, 1966

-- 2c J Contract No. M A S 9-3924 27 6

Submitted t o

National Aeronautics and Apace Administration Planned Spacecraft Center

Houston, Texas

b

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TABU OF CONTENTS

1. INTRODUC !IT ON

2. TECHNICAL DISCUSSION

2.1 RF Modulatiorl. 2.2 RF Buer Amplifier 2.3 Receiver RF 2.4 I!? AmpWier

3 . PROJECT SCHEDULE

3.1 PERT Chart 3.2 Estimate of Thin-Film Components

4. MODULE PROCESSING INFORMATION

Appendix A -0 Deposition Mask Drawings

Page

1

2

2 4 4 7

7

9 11

ll

A-1

F

LIST OF ILLUSTRATIONS

Figure

1 w 2 R F

Modulation Stages,

Power Amplifier

Oscil lator and "ripler

3 Receiver RF Amplifier

k IF Amplifier, AGC, and Audio Circuits

PERTChart

Page

3

5 6

8

10

1. INTRODUCTION

T h i s report f o r t he third quarter of Phase B is submitted i n om-

pliance with Contract NAS 9-3924 between NASA-HousCon and Melparp Inc. The

ultimate objective of the contract is to construct a thin-film personal

communication and telemetry system, During Phase B, the objective i s t o

design and qonstruct the circuit modules t ha t will be used i n Phase C to

package the t o t a l syatem. Each module i s designed t o incorporate thin-film

c i r c u i t r y t o the greatest; extent gossipls.

Progress during the past quarterr did not meet our e a r U e r expec$ations.

Three problem areas which contributed delays are:

1. Epoxy packaging of VCO's: The center frequency and range of the

VCO's changed a f t e r pottiqg,

2. Thin-film t rans is tor stakciliby and noise: Attempts t o use the

tun-f i lm Cretnsirstors have bssn d$acouragiqg ouwg t o t h e i r dc i n s t a b i l i t y

and high noise figure.

3. 300-Mc tuning procedures: It i s desirable t o use fixed capacitors

and tunable inductors i n the tkdn-film RF modules,

d i f fqcul t ies i n designing the capacitor networks i n t h i n - f i b form.

We have encowtered some

These problems will not in te r fe re with the overal l t ask objective,

but will require tha t the module delivery schedule be modified,

FERT chart is included i n this report,

A revised

The epoxy coating tha t has been used f o r an outer oovering on the

modules provtdes a r ig id package, but appareQtly induces stress on the cir-

cui t camponents,

require t ha t the bd iv idua l components remain essenltially unchanged a f t e r

I n the case of the VCO's, the c i r c u i t specifications

1

potting.

epoxy covering and del iver the modules with the wax covering only o r with an

outer coating of RTV.

I n the next attempt a t packaging the VCOfs, we w i l l eliminate the

Development work is continuing on the thin-film transis tors . We were

able to use the t rans is tors i n the source followers i n the "Summing Resistqr

Netwrk" module.

o the r module s . We will continue t o evaluate the t r ans i s to r s f o r use i n Che

The HF tuning procedure is d i f f i c u l t because the in te rs tage capacitor

networks determine both the impedance match and the frequency of operation.

The thin-film oapacitors must be deposited with close tolerance t o the d e s i p

values because trimming methods for capacitors introduce paras i t ic indvctancs

or resistance.

trimming procedure,

Further design e f for t w i l l be required t o f ind a suitable RF

2, mmcAL DISCUSSION

I n previous repor%s, we have given the schematio and c i r c u i t d e s c r i p

t i o n of the t r a n m i t t e r except for RF modulation and power output stages,

These a i r c u i t s and the receiver c i r c u i t s will be described i n t h i s report.

2.1 BF ModulaOion

A c i r cu i t diagram of the RF modulation, osc i l la tor , and 'Fripler stages

is shown i n figure 1,

quarterly report (Phase B),

0.7 V peak t o peak when loaded with the fol lowbg stage.

The osc i l l a to r and t r i g l e r w e r e described i n the first

The RF signal f r o m the t r i p l e r i s approxhate3.y

A single stsge of

gate modulation w i l l not provide the required l i n e a r i t y using insulated-gate

f ie ld-effect transistors. When a second stage is modulated i n tandem, as

2

E6923 0 TO-6 V BIAS

~ MODULATION IN

Figure 1. R F Modulation 'stages, Oscillator and Tripler

TO POWER AMPLIFIER

shown i n figure 1, the modulation is l inea r t o within 4 percent and the

percent of modulation is greater than 9!$* The t rans is tor used i n these

stages i s the KMC 1201. Resistors (330 K) are placed between gate and

source t o protect the t ransis tors fram damage owing t o s t a t i c charges,

The modulation signal frm the "Filter and RF Modulator Moduleft drives

both stages identically, Fixed capacitor impedance transformatiop networks

are used between stages and tuning is accomplished with inductors.

output is an AM signal with a peak-to-peak amplitude of 8 V in to a 2 K

load, o r approximately 1 mW carr ier power, This signal i s then fed t o

the transmitter power amplifier.

2.2 HF Power Amplifier

The

The low-power modulated signal. is fed in to a conventional t rans is tor

amplifier; i.e., g s i n d e stage of c lass A followed by two stages of c lass C.

(See f$gum 2.) The f i n a l output can be driven t o 16 V peak t o peak acrogs

50 ohms f o r a peak power of 820 mW. U t h o r without modulation the oar r ie r

power is 1 9 mW. !-

2.3 Bceiver RF

F'igw 3 shows the receiver FU? input, A 2N3823 FET i s used aq the RF

amplif$er,

t ransis tor .

An IF frequency-bypass network i s included i n the interstage coupling net

wgrk. The liF stage has B gain of 10 dB and the t o t a l voltage gain (taking

The input network patches the SO-ohm antenna t o the input of @ae

Thq second stage is a m i x e r using the same type of transistor. .z I*

f

I

i n t o account the conversion gain of the mixer) i s approximately 100. There

are two AGC points i n the receiver RE' as indicated i n figure 3. The RF AGC

detunes the input so t h a t saturation is avoided a t the maximum input signal

c levels.

4

*t

Y

E6924

C-l

I ,I

Figure 2. RP Power Amplifier

s-c

PEAK - PEAK E,

PEAK POUT

PEAK PIN

N

= 16 VPP

= 820 MW

= 4.1 W

= 20%

I 1 ' ff 1 I 8 II I

NOTE: BYPASS CAP S 6 0 0 p f MIXER BIAS 8, AGC

4 '

E6925

- 200 R

4 b 50K

E iBP - - 0.04

4 Pf 2N3823

4 1 0.06

- - 1 OK

RF - AGC ; - - BP O

B+

L io SIG IN

Figure 3. Receiver RF Amplifier

6

The loca l q sc i l l a to r i q essent ia l ly the same a s the oscil lator+

t r i p l e r shown i n figure 1.

2.4 IF' Amplifier 4

The I F amplifier, A N , detectors and audio amplifier are shown i n

figure 4. the first section

(Q1 through Q,) consists of four amplifier stages and is used to develop

an AGG signal f o r the RF ampllfier end mixer; the second section i s five

The IF amplifier consists of two sections:

stages with three sections of gain control.

f o r AW amplifiers ra ther than amplifying the detected s ignals with dc

amplifiers,

is designed tq be compatible with thin-film device capabili t ies.

This method uses IT stages

!he resul t ing system is not so affected by b ias changes and

Three separate detectors are used t o provide AGC. The first IF

sect ion drives two detectors, one f o r the Eli' stage and one f o r the lllixer

stage. The third AGG detector is driven from the second IF section t o

provide i ts own A N . A fourth detector is used t o provide the audio signal,

Each stage i n the I F amplifier consists of an amplifier ard a s o w e

follower, This i s necessargto prevent sapacitive loading from one stage

t o the next. A frequency selective twin-T f i l t e r is used i n the second

sect ion t o provide some degree of s e l ec t iv i ty aml noise reducC;Lon. The

output o f Q17 i s fed back t o the input of Q through &he twin-T ne+work. l4

3. PROJECT SCHEDlJU

The objective fo r this phase of tbe project i s t o del iver finisbed

modules with schematics ard specifications,

7

8 .

i 8 s 1 It Jc 3 t: II I 0 I I 8 1 I 1

8 ' E6926

0.005~ f

47af

i

l00K

1K ? *lo” 0 . 0 0 2 N f -- T %Opf

7 5 0 r E 2 y 0 .005~ f

%OPf

- P +lev

45.5H 45. H

- - I

4 AUDIO OUTPUT

‘8-& Figure 4. IF Amplifier, AGC, and Audio Circuits

The following revised list represents the complete set of modules

tha t w i l l be required f o r the transceiver along with notations on the

progress made t o date:

Module #l - Transmitter Audio Amplifier:

Module #2 - 2.3-KC Low-Pass EYlter:

Modules #3-@ - VCO's: Two modules were completed but changed

Ready f o r Delivery,

Ready fo r deposition,

character is t ics when potted. A secmd attempt a t packaging is i n process.

Modules #lo, #ll, #12 - Twin-T Notch Fi l te rs :

Modules #13 and #l4 - Diplexer &it, IMplexer Receive:

delivered.

Redesign is

required.

Module #ls - Mixer Operational AmpUfier:

Modules #16 and #l? - Xmit RF, Receiver RF:

Ready f o r packaghg.

Thin-film design i n

progress.

Modules #18-#U: - Receiver IF, AGC and Audio: Ready f o r mask fabr i -

cation.

Module #22 - Summing Resistor Network:

Modules #23, #23 - Power Supply: These modules w i l l not be f ina l ized

Ready for delivery.

u n t i l a l l okher modules are reduced t o t h i n film form. '

3.1 PERT Chart

A revised - PERT chart i s shown i n figure 5. The ta rge t dates f o r the

completion of modules have been changed t o r e f l ec t the present estimates.

Some of the modules w i l l not be completed during Phase B.

af fec t the overall system integration, since discrete component modules

can be used t o evaluate the finished portion of the system.

This will not

9

Y

I5 API(L I Y." I S M T

21 FE8

T R u l y c Am EVALUITION

I SEPT

DELIVERY

ISNOV

IRlY11NG A N D EVALUATION

IS Dfc

TUIYIWG AND EVALUATION

I , JAN

TRIUWNG AND EVALUATION

TRIUYNGIND EVALUATION

- .

W W W . m u . I5 APRIL 1 \ I

\ I5 APRIL

6 SEPT

f6- t .. I Figure 5. PERT Chart

10

a

1 I

3.2 Estimate of Thin-Film Components

Table I shows the pa r t count f o r the various types of components.

The current percentage figure for thin-film cmponents i s 75.

i s lower than previously reported owing t o the increased use of d i scre te

t ransis tors .

be incorporated i n the design.

T h i s figure

As improvements a r e made i n thin-film transis tors , they will

4. MODULE PROCESSING INFORMATION

Appendix A contains the deposition mask drawing for:

a.

b. Operational amplifier

e. Audio amplifier trenhnaitter

d.

Summing resistors and source followers.

2.3-90 filter and RF modulator

5. SUMMARY AND NEXT PERIOD OBJECTIVES

Same delays have occurred i n the fabrication of thin-film modules.

Most of the modules wi l l be completed during the next quarter and system

integrat ion can begin on schedule. The RF and power supply modules will

not be reduced t o thin-- form u n t i l the first quarter of Phase 0.

Fhristing discrete component modules will be used f o r the RE' portion during:

the ea r ly par t of system integration.

TABLE I

COMPONEXT PARTS FOR THIN-FIU

Transistors co i l s Discrete Discrete T,F.

Transmitter audSo -PI 3

2 . 3 - ~ ~ f i l t e r 2

VCO’S (7) 28

D i plexe r s 4 Operational

amplifier 3

Tranmi t te r RE’ modules 7 9

Receiver RF modules 5 6

amplifiers 10

Detector 8e AGC 9

Receiver audio 2

Summing res i s tors 2

Power supply - - - 8

79 15 4

TRANSCEIVER

R TeF - 7

9

42

18

13

15

11

20

23

5 13

C Diodes T.F. u. Other - - 3 14

5 14 4 18

4

7

20

19

10

16 1

5 1

3

1 crys t a l

1 crys ta l

15 10 8 discrete 1 9 1 134 16/8 2

NOTE: The power supply will require 4 discrete capacitors. Audio amp1 i n receiver will requim 1 discrete capacitor. These figurns are f o r the primary system, are:

The t o t a l s f o r both systems

Transistors 127 discrete Coils 30 discrete 4 t h i n - f i b Re sis tqrs - 304 thin-fikn Capacitors 10 discrete 225 thin-film

18 thin-film Diodes 16 discrete Crystal s 4 discrete _-

12

II t o 1 I s

t

APPEXDIX A

DEPOSITION MASK DRAWINGS

A-1

E6927 0 0 0 0 0 0

(a) Chromium Conductor Mask

(b) First Conductor Mask

Figure A-1. Summing Resistor and Source Follower Masks A-2

E6927

(c) Resistor Mask

(d) Dielectric Mask

Figure A-1. Summing Resistor and Source Follower Masks (Continued) A-3

E6927

0 0 0

.

U e I

(e) Second Conductor Mask

1

-

(9 Protective Coatina Mask

F i w e A-1. Summing Resistor and Source Follower Masks (Continued)

E6928 1 8 '

0

0

0

0

E 0

(1 0

0

(a) Chromium Conductor Mask

0 00 (b) First Gnductor Mask

Figure A-2. Operational Amplifier Masks A-5

E6928

(e) Low Value Resistors

(d) High Value Resistors

Figure A-2. Operational Amplifier Masks (Continued)

A-6

t 8 8 1 I 8

E6928

0 n o 0

0 0

;(e) Dielectric Mask

I I

- 0 -n

n - b a Y

n - 0 1 1 - 0 n

n - I&- - u *

b J P-

i .

(f) Second Conductor Mask

Figure A-2. Operational Amplifier Masks (Continued) A-7

E6928 I * 1'

(9) Protective Coating Mask

Figure A-2. Operational Amplifier Masks (Continued)

A-a

E6929 1

000000000000

0

0-

0

1 1 1 1 1 l l l 0 1 1 1 1 1 0 0 1 1 1 1 1 0

(a) .Chromium Conductor Mask

I, 0 0

0 Y

o

Figure A-3.

(b) First (Conductor Mask

Audio Amplifier and Transmitter Masks

A-9

I 1 I 1 1 8 8 I 1 8 I

(c) Low Value Resistors

(d) High Value Resistors

Figure A-3. Audio Amplifier and Transmitter Masks (Continued)

A-10

,I I ' I 8

I 8 1 -1 I

E6929

0

8 8 1 I 8 8 8

8 a

(e) Dielectric Mask

008 0

0 -- n

(4 Second Conductor Mask

Figure A-3. Audio Amplifier and Transmitter Masks (Continued)

A-11

E6929 I 3 .

8 8 I 8 I I 8

00-

(9) Protective Coating Mask!

Figure A-3. Audio Amplifier and Transmitter Masks (Continued)

A-12

I ’ E6930

I ‘ I I 8

n I 8 8 I I I I I

(a) Chromium Conductor Mask

(b) First Conductor Mask

Figure A-4. 2.3-KC Filter and RF Modulator Masks A-13

I I I I "f

(1 I I I I d 1 1 I

0

(c) Resistor Mask

0 n u

(d) Dielectric Mask

Figure A-4. 2.3-KC Filter and RF Modulator Masks (Continued)

A- 14

E6930

1

I I Y 1

1 I I I I I 1

E I

m

m

0

0

a 0 I n v 'B -0

0

(e) Second Conductor Mask

'T I

(f) Protective Coating Mask

Figure A-4. 2.3-KC Filter and RF Modulator Masks (Continued)

A-15