HARRIS TR-0017-E Sitepro Base Station User Manual TX Synth

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Maintenance Manual

LBI-38640G

VHF TRANSMITTER SYNTHESIZER MODULE

19D902780G1

TABLE OF CONTENTS

Page

DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Front Cover

GENERAL SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

CIRCUIT ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

VOLTAGE CONTROLLED OSCILLATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

RF AMPLIFIERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

REFERENCE BUFFER AMPLIFIER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

PRESCALER AND SYNTHESIZER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

LOOP BUFFER AMPLIFIERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

AUDIO FREQUENCY AMPLIFIER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

VOLTAGE REGULATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

LOGIC CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

TEST PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

ALIGNMENT PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

OUTLINE DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

ASSEMBLY DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

SCHEMATIC DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

PRODUCTION CHANGES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

IC DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

DESCRIPTION

The principle function of the Transmitter Synthesizer

Module is to provide the RF excitation for input to the

MASTR III station power amplifier. The output of the syn-

thesizer is a frequency modulated signal at the desired fre-

quency. The module contains the following functional

blocks:

•A voltage controlled oscillator.

•A chain of integrated circuit RF Amplifiers.

•A reference buffer amplifier.

•Dual modulus prescaler and synthesizer integrated

circuits.

•Loop amplifiers and passive loop filter.

•An audio amplifier and a pre-modulation integrator.

•IC voltage regulators for +5 and -5 Vdc. A discrete

component regulator for +8 Vdc, and an Opera-

tional Amplifier regulator for +4 Vdc.

•Logic circuitry: address decoder, input signal gates,

and a lock indicator circuit.

M/A-COM Wireless Systems

3315 Old Forest Road

Lynchburg, Virginia 24501

(Outside USA, 434-385-2400) Toll Free 800-528-7711

www.macom-wireless.com Printed in U.S.A.

Table 1 - General Specifications

ITEM SPECIFICATION

FREQUENCY RANGE 136 to 174 MHz

in 4 bands 136 to 144 MHz

142 to 152 MHz

150 to 162 MHz

160 to 174MHz

RF POWER OUT(50 Ohm load) 10 to 13 dBm

(10 to 20 mW)

RF HARMONICS <-30 dBc

NON-HARMONIC SPURS

1 to 200 MHz <-90 dBc

200 MHz to 1 GHz <-60 dBc

CARRIER ATTACK TIME <50 ms

REFERENCE INPUT

input level 0 dBm ±1.5dB

input impedance 50 Ohm

frequency 5 to 17.925 MHz (must be integer divisible by

channel spacing)

MODULATION SENSITIVITY 5 kHz peak dev/1 Vrms

AF INPUT IMPEDANCE 600 Ohm

AF RESPONSE

10 Hz ±1.5 dB

1000 Hz 0 dB reference

3 kHz ±1.5 dB

10 Hz SQUARE WAVE MODULATION <10%

Sq wave droop

HUM & NOISE -55 dB

POWER REQUIREMENTS 13.8 Vdc @ 275 mA

-12.0 Vdc@ 10 mA

CIRCUIT ANALYSIS

VOLTAGE CONTROLLED OSCILLATOR

Transistor Q1 and associated circuitry comprise a low noise

Voltage Controlled Oscillator (VCO). Inductor L1 and associ-

ated capacitors form the oscillator resonant circuit (tank). The

noise characteristic of this oscillator is dependent on the Q of

this resonant circuit. The components used in the tank are

specified to have especially high Q. Diode D1 aids in setting

the bias point for low noise operation. (Any field replacement

of oscillator parts should use identical parts).

Switches SWIA, SWIB, SWIC and SWID set the fixed

capacitance in the tank and therefore set the frequency range

over which the oscillator can be voltage tuned. Table 2 shows

the switch settings for the various frequency ranges.

Switches SW1E (SW#5) and SW1F (SW#6) also set the

fixed capacitance in the tank and perform the frequency

trimming function. These two switches are factory set and

should not need resetting unless any oscillator components

are changed. (See alignment procedure section of this man-

ual for instructions on resetting SW1E and SW1F).

The oscillator frequency is voltage tuned by the signal

applied through R5 and L5 to the two varicap diodes D2 and

D3. Additionally, audio modulation is applied as an AF

voltage to the two varicap diodes. This AF voltage varies the

oscillator frequency at an audio rate (i.e., it frequency modu-

lates the oscillator). Low frequency audio is applied along

with the varicap control voltage through R5 and L5 while

high frequency audio (MOD) is applied via C16.

Resistors R6 through R9 provide a two volt negative bias

on the varicap diodes.

Figure 1 - Block Diagram

Transistors Q101 and Q102 and associated circuitry form

the oscillator enable switch. This switch allows the station

control circuitry to turn the VCO ON or OFF via the

ANT_REL line. Setting the ANT_REL line to a logic low

causes Q102 to conduct. The five (5) volt output at Q102

collector (OSCON) enables the fault indicator gates, U705C

and U705D, and turns on Q101. Q101 starts to conduct,

providing a ground path for Q1. This turns ON the VCO.

RF AMPLIFIERS

Integrated circuits U201 and U202 and U203 and tran-

sistor Q201 form a chain of RF amplifiers. These amplifiers

serve two purposes; amplifying the RF signal for input to the

power amplifier and providing a signal to the Phase-Locked

Loop (PLL) .

Integrated circuits U201, U203 and transistor Q201

provide amplification for the RF signal which will be fed to

the station power amplifier. U201 operates with a gain of

about 5 dB. Its output is fed to a resistive signal splitter

composed of R203 through R210.

One of the resistive signal splitter outputs drives U203.

U203 operates with a gain of about 10 dB. Q201 and associ-

ated circuitry comprise the output amplifier which has a gain

of about 6 dB. This amplifier is followed by a 190 MHz

cutoff low -pass filter (C216, C217, L203 and L204) and a 6

dB resistive attenuator (R219 through R221). The final out-

put at the front panel BNC connector (J2) is nominally 11.5

dBm into a 50 ohm load.

Table 2 - Frequency Range Switch Settings

FREQUENCY

RANGE (MHz) SW1A

(SW#1) SW1B

(SW#2) SW1C

(SW#3) SW1D

(SW#4)

160-174 OPEN OPEN OPEN OPEN

150-162 CLOSED OPEN CLOSED OPEN

142-152 OPEN CLOSED OPEN CLOSED

136-143 CLOSED CLOSED CLOSED CLOSED

LBI-38640G

The other output of the resistive splitter drives U202.

U202 is a buffer amplifier with a gain of about 10 dB. U202

drives the synthesizer prescaler (i.e. it provides a signal to

the PLL).

REFERENCE BUFFER AMPLIFIER

Transistor Q401 and associated components comprise a

buffer amplifier for the reference oscillator signal. (The

reference oscillator signal is produced by the receiver syn-

thesizer module of a MASTR III station.) The 0 dBm refer-

ence oscillator signal is fed through the front panel BNC

connector J1. Resistor R405 provides a 50 ohm load to the

reference oscillator. The output of the Reference Buffer

Amplifier is fed directly to the synthesizer integrated circuit.

The output level at TP9 is approximately 3 volts peak to

peak.

PRESCALER AND SYNTHESIZER

Integrated circuit U402 is the heart of the synthesizer. It

contains the necessary frequency dividers and control cir-

cuitry to synthesize output frequencies by the technique of

dual modulus prescaling. U402 also contains an analog

sample and hold phase detector and a lock detector circuit.

Within the synthesizer (U402) are three programmable

dividers which are loaded serially using the CLOCK, DATA,

and ENABLE inputs (pins 11, 12, and 13 respectively). A

serial data stream (DATA) on pin 12 is shifted into internal

shift registers by low to high transitions on the clock input

(CLOCK) at pin 11. A logic high (ENABLE) on pin 13 then

transfers the program information from the shift registers to

the divider latches.

The reference signal is applied to U402 pin 2 and divided

by the "R" divider. This divides the reference signal down to

a divided reference frequency (Fr). The typical reference

frequency is 12.8 MHz and the typical divided reference

frequency is 5 kHz providing for synthesizer steps of 5 kHz

for use with both 25 kHz and 30 kHz channel spacing. Other

channel spacings are possible by providing proper program-

ming.

The "A" and "N" dividers process the loop feedback

signal provided by the VCO (by way of the dual modulus

prescaler U401). The output of the "N" divider is a divided

version of the VCO output frequency (Fv).

Synthesizer U402 also contains logic circuitry to control

the dual modulus prescaler U401. If the locked synthesizer

output frequency is 150 MHz. The prescaler output nomi-

nally will be equal to 2.34375 MHz (150 MHz/64). This

frequency is further divided down to Fv by the "N" divider

in U402. Fv is then compared with Fr in the phase detector

section.

The phase detector output voltage is proportional to the

phase difference between Fv and Fr. This phase detector

output serves as the loop error signal. This error signal

voltage tunes the VCO to whatever frequency is required to

keep Fv and Fr locked (in phase).

LOOP BUFFER AMPLIFIERS AND LOOP

FILTER

The error signal provided by the phase detector output is

buffered by operational amplifiers (op-amp) U501A and

U501B. The audio modulation signal from U601B is also

applied to the input of U501B. The output of U501B is the

sum of the audio modulation and the buffered error signal.

The output of the second buffer (U501B) is applied to a

loop filter consisting of R506, R507, R508, C505 and C506.

This filter controls the bandwidth and stability of the synthe-

sizer loop. The VHF transmitter synthesizer has a loop

bandwidth of only several Hertz. This is very narrow, result-

ing in an excessively long loop acquisition time. To speed

acquisition, switches U502A and U502C bypass the filter

circuit whenever an ENABLE pulse is received by the Input

Gates.

AUDIO FREQUENCY AMPLIFIER

The transmitter synthesizer audio input line is fed to

U601A. U601A is configured as a unity gain op-amp. Resis-

tor R601 sets the 600 ohm input impedance of this amplifier.

(NOTE: Data for digital modulation is fed to the synthesizer

through the audio input line).

The amplifier output is split into two components and fed

to two variable resistors VR601 and VR602. VR601 sets the

level in the low frequency audio path and VR602 sets the

level in the high frequency audio path. (There is no clear

break between the low and high frequency ranges. All voice

frequencies are within the high frequency range. The low

frequency range contains low frequency data components).

The wiper of VR601 (low frequency path) connects to

the input of U601B, the pre-modulation integrator. U601B

performs the function of a low-pass filter and integrator. The

integrator output is summed with the PLL control voltage at

the input of loop buffer amplifier U501B. This integrated

audio signal phase modulates the VCO. The combination of

pre- integration and phase modulation is equivalent to fre-

quency modulation.

The wiper of VR602 (high frequency path) is connected

to the modulation input of the VCO through C16.

VOLTAGE REGULATORS

U301 and U303 are monolithic voltage regulators (+5

Vdc and -5 Vdc respectively). These two voltages are used

by synthesizer circuitry. The +5 V regulator output is also

used as a voltage reference for the +8 Vdc discrete regulator

circuit.

U302A, Q302 and associated circuitry comprise the +8 volt

regulator. Most module circuitry is powered from the +8 volt

line. The regulator is optimized for especially low noise per-

formance. This is critical because the low noise VCO is pow-

ered by the +8 volt line.

The +8 Vdc line also feeds the +4 Vdc regulator, U302B

and associated resistors. The +4 Vdc regulator provides a bias

voltage for several op-amps in the module.

LOGIC CIRCUITS

Logic circuitry (other than that inside the synthesizer IC -

U402) consists of the following:

•An address decoder

•Input gates and level shifters

•Lock Indicator circuitry

The address decoder, U702, enables the Input Gates when

the A0, A1, and A2 input lines receive the proper logic code

(110 for the transmitter synthesizer). After receiving the proper

code, Y3 (U702-12) sends a logic low signal to U701C. U701C

acts as an inverter and uses the logic high output to turn on

Input Gates U701A, U701B, and U701D. The Input Gates

allow the clock, data and enable information to pass on to the

synthesizer via the level shifters. The Level Shifter Transistors

Q701, Q702 and Q703 convert the 5 volt gate logic level to the

8 volt logic level required by the synthesizer U402.

The Fault Indicator circuitry indicates when the synthe-

sizer is in an out-of-lock condition. The fault detector latches,

U705A and U705B are reset by the enable pulse during initial

loading of data into the synthesizer. If at any time afterwards

the lock detector signal (LD) goes low, the high output of

U705B will cause the output of gates U705C and U705D to go

low. The low output from U705C causes Q704 to turn off, thus

turning on the front panel LED (CR701). The output of U705D

(FLAG) i s connected to J3-13C for external monitoring of the

Synthesizer Module. A logic low on the FLAG line indicates

an out-of-lock condition.

MAINTENANCE

RECOMMENDED TEST EQUIPMENT

The following test equipment is required to test the synthe-

sizer Module:

1. RF signal source for 12.8 MHz, 0 dBm reference (in-

cluded with item 10)

2. AF Generator or Function Generator

3. Modulation Analyzer; HP 8901A, or equivalent, or a

VHF receiver

4. Oscilloscope; 20 MHz

5. DC Meter; 10 meg ohm (for troubleshooting)

6. Power Supply;13.8 Vdc @ 350 mA 12.0 Vdc @ 25

7. Spectrum Analyzer; 0-1 GHz

8. Frequency Counter; 10 MHz - 250 MHz

9. Personal Computer (IBM PC compatible) to load fre-

quency data

10.Service Parts Kit, (TQ0650), (includes software for

loading frequency data)

TEST PROCEDURE

(Steps 5, 6, and 7 can be done using a modulation analyzer

or VHF receiver with 750us de-emphasis switchable in or out.

1. Program synthesizer at 167.5 MHz using the System

Module personality (or Test Software if using RF

Test Fixture TQ-0650).

Verify lock (flag = high)

Verify front panel LED is off.

2. Measure output frequency.

Verify frequency = 167.5000 MHz ±100 Hz.

3. Measure harmonic content (335 MHz, 502.5MHz).

Verify 2nd harmonic is 30 dBc.

4. Measure RF power output into 50 ohm load.

Verify 10 to 13 dBm (10 to 20 mW).

5. Measure AF distortion with standard modulating sig-

nal input.

Verify <5%.

6. Measure Hum and Noise relative to 0.44 kHz average

deviation, (de-emphasis on).

Verify <-55dB

7. Measure AF response at 300 Hz, 1 kHz (ref) and 3

kHz, (de-emphasis off).

Verify within ±1.5 dB with respect to 1 kHz refer-

ence.

8. Verify lock at different frequencies.

a. Close switches SW1A and SW1C.

b. Program synthesizer at 156 MHz.

Verify LED is off.

LBI-38640G

c. Open switches SW1A and SW1C and close

switches SW1B and SW1D.

d. Program synthesizer at 147 MHz.

Verify LED is off.

e. Close switches SW1A, SW1B, SW1C and

SW1D.

f. Program synthesizer at 139.5 MHz.

Verify LED is off.

g. Open switches SW1A, SW1B, SW1C and

SW1D.

ALIGNMENT PROCEDURE

1. Set all sections of SW1 to the open position.

2. Apply +13.8 Vdc and -12 Vdc. Verify the current

drain on the 13.8 volt supply is <300 mA and the cur-

rent drain on the -12 volt supply is <20 mA.

3. Program the synthesizer at 175 MHz. Set SW1E and

SW1F (4 possible Combinations = both closed, both

open, E open and F closed, or E closed and F open)

to set Vtest (pin 23A of 96 pin connector) as close to

6.0 volts as possible, but always between 5.5 and 6.5

volts.

4. Program synthesizer at 167.5 MHz for the following

three adjustments

•Set VR602 for 4.5 kHz peak deviation with a standard

modulating signal applied to the audio input.

•Set VR601 for 4.4 kHz peak deviation with 1.0 Vrms,

10 Hz sine wave audio applied to module AF input.

•Apply a 10 Hz 1.4 Vpk square wave (same peak value

as 1.0 Vrms (sine wave) to module AF input. Adjust

VR601 slightly for the flattest demodulated square

wave using a modulation analyzer or receiver (no de-

emphasis) and an oscilloscope . The maximum net

variation in voltage over 1/2 cycle is 10%.

The following service information applies when align-

ing, testing, or troubleshooting the TX Synthesizer:

•Standard Modulating Signal = 1 kHz sinusoidal

voltage, 1.0 Vrms at the module input terminals

(600 ohm Rin).

•The input audio level for setting the 4.5 kHz or 10

Hz (or 7 Hz) deviation should always be 1.00

Vrms.

•In the modulation adjustment, any reference to 0.6

Vrms refers to the voltage level for a STANDARD

signal, or usually 60% (3.0 kHz) of maximum

deviation. The 0.6 Vrms will produce 60% of full

deviation.

•Logic Levels:

Logic 1 = high = 4.5 to 5.5 Vdc

Logic 0 = Low = 0 to 0.5 Vdc

•Transmitter Synthesizer Address = A0 A1 A2

= 110

•Synthesizer data input stream is as follows:

14-bit "R" divider most significant bit (MSB) =

R13 through "R" divider least significant bit

(LSB) = R0

10-bit "N" divider MSB = N9 through "N" divider

LSB = N0

7-bit "A" divider MSB = A6 through "A" divider

LSB = A0

Single high Control bit (last bit)

Latched When Control Bit = 1

DATA ENTRY FORMAT

Latched When

Control Bit = 1

Data in Last A0 ---- A6 N0 ---- N9 R0 ---- R13

Bit LSB MSB LSB MSB LSB

Control Bit

For the transmitter synthesizer, 5 kHz channel

spacing

R=2560

N = integer part of (frequency in kHz) / (320)

A = (frequency in kHz)/(5) - 64*N

All numbers must be converted to binary.

•ANT_REL line must be logic low (0V) in order to

lock synthesizer.

•Synthesizer lock is indicated by the extinguishing

of the front panel LED indicator and a logic high

on the fault flag line (J3 pin 1 3C).

•Always verify synthesizer lock after each new data

SYMPTOM CHECK INCORRECT READING

(CORRECT READINGS SHOWN) INDICATES DEFECTIVE COMPONENT

SYNTHESIZER FAILS TO LOCK Check DC voltages

+5 V @ U301 Pin 1 U301 or associated components

+8 V @ Q301 collector U302, Q301, Q302 or associated components

- 5 V @ U303 Pin 1 U303 or associated components

Check 12.8 MHz reference signal No reference signal to front panel BNC or

3V P-P, 12.8 MHz @ TP9 or U402 Pin 2 Q401

Check oscillator signal

11.5 1.5 dBm 125 to 180 MHz at Proceed to "Low/No RF output" below

front panel BNC

Check prescaler output

1V P-P, 2.5 MHz @ U401 Pin 4 U202, U401

Check CLOCK, DATA, ENABLE

While loading frequency data into Wrong address or

synthesizer Check 8V logic signals @ U701, U702, Q701, Q702, Q703

Pins 11, 12, 13 of U402

Check Phase detector output

5 kHz random signal @ U501 Pin 7 U402, U501

Low/No RF Output Check oscillator

LESS than 0.5 Vdc @ TP3 or collector Synthesizer not keyed (low on ANT relay line)

of Q101 or Q101, Q102

50 mV, 125 to 180 MHz @ TP4 Q1

No Modulation Check RF chain

0 dBm, 125 to 180 MHz @ TP6 U201

+5 dBm, 125 to 180 MHz @ TP7 U203

11.5 ±1.5 dBm to 180 MHz at front Q201

panel BNC

No Modulation Check AF amplifier

Apply 1V, 1 kHz signal to TX/Audio/ Hi U601

Check 1V signal @ TP12 or U601 Pin 1

TROUBLESHOOTING GUIDE

TROUBLESHOOTING

A troubleshooting guide is provided showing typical

measurements at the various test points. The location of the

test points and adjustments are shown in Figure 2.

Perform step 3 only if switch SW1 has been replaced.

Otherwise go to step 4.

NOTE

SERVICE NOTES

LBI-38640G

OUTLINE DIAGRAM

VHF TRANSMITTER

SYNTHESIZER BOARD

19D902779G1

(19D902779, Sh. 1, Rev. 13)

Figure 2 - Test Point Locations

LBI-38640G

ASSEMBLY DIAGRAM

VHF TRANSMITTER SYNTHESIZER MODULE

19D902780G1

(19D902780, Sh. 1, Rev. 7)

LBI-38640G

SCHEMATIC DIAGRAM

VHF TRANSMITTER SYNTHESIZER

19D902780G1

(19D902622 Sh. 1, Rev. 12)

LBI-38640G

SCHEMATIC DIAGRAM

VHF TRANSMITTER SYNTHESIZER

19D902780G1

(19D902622, Sh. 2,Rev. 12)

LBI-38640G

SCHEMATIC DIAGRAM

VHF TRANSMITTER SYNTHESIZER

19D902780G1

(19D902622, Sh. 3, Rev. 12)

LBI-38640G

PARTS LIST LBI-38640G

PARTS LIST & PRODUCTION CHANGES

PRODUCTION CHANGES

Changes to the equipment to improve performance or to simplify

circuits are identified by a Revision Letter which is stamped after the

model number of the unit. The revision stamped on the unit includes

all previous revisions. Refer to the partls List for the descriptions of

parts affected by this revision.

Rev. A - Transmitter Synthsizer Board - 19D902779G1

To improve reliability, changed C21, C23, C24, C25, C216,

C305, L203, L204, R211, R219, R220 and R221. Deleted

C26 and C212 and added C217.

C21 was: 19A702236P11, 2.7 pF.

C23 was: 19A702236P19, 5.6 pF.

C24 was: 19A702236P9, 1.8 pF.

C25 was: 19A702236P13, 3.3 pF.

C216 was: 19A702236P21, 6.8 pF.

C305 was: 19A705205P6, 10 µH.

L203 was: 19A705470P18, 0.27 µH.

L204 was: 19A705470P13, 0.10 µH.

R211 was: 19B800607P100, 10 ohms.

R219 was: 19B800607P221, 220 ohms.

R220 was: 19B800607P270, 27 ohms.

R221 was: 19B800607P221, 220 ohms.

Rev. B - Transmitter Synthsizer Board - 19D9027791

To improve Lock-on at low end of board and to improve

stabilization of +8 volt power supply. Changed C312, R204

and R310; replaced R206 with C219 and R207 with L205.

C312 was: 19A702061P99, 1000 pF.

R204 was: 19B80607P270, 27 ohms.

Rev. C - Transmitter Synthsizer Board - 19D902779G1

To improve the margin of stability on the +8 Vdc power

supply, changed C312 and R310, and added C314 and

R313.

C312 was: 19A705205P2, 1 µF.

R310 was: 19B800607P100, 10 ohms.

Rev. D - Transmitter Synthsizer Board - 19D902779G1

To correct loading problem.

R209 was: 100 ohms (19B801486P101).

R411 was: 4.7k ohms (19B800607P472).

R707 was 47k ohms (19B800607P473).

REV. E - Transmitter Synthesizer Board - 19D902779G1

To accommodate SOG synthesizer IC package U402 (PLCC

package discontinued). Modified printed wire board layout

(Printed wire board changed from 19D902644P1R5 to

19D902644P1R6). Added new U402. U402 was

19B800902P5. Installed RC compensation network resistor

R314 and capacitor C315 in 10-volt regulator circuit. In-

stalled item 9 RF shielding grommets (19B802690P1) on

two BNC connectors of input/output RF ports.

REV. A - Transmitter Synthesizer Module 19D902780G1

To install RF shielding grommets. Installed item 9 RF shield-

ing grommets (19B802690P1) on two BNC connectors of

input/output RF ports.

REV. F - Transmitter Synthesizer Board - 19D902779G1

To improve marginal power output at the high end of the VHF

Band (174 MHz). Changed inductor L203 from 0.18 µH

(19A705470P16) to 0.15µH. Changed resistor R220 from

39 ohms (19B800607P390) to 22 ohms. Inductor L203 was

a 19A705470P16. Resistor R220 was a 19B800607P390.

REV. B - Transmitter Synthesizer Module 19D902780G1

To install a cover that has a conductive gasket. Changed

item 3. Item 3 was a 1919D902509P2.

REV. G - Transmitter Synthesizer Board 19D902779G1

To increase the base current of transistor Q101 and ensure

saturation during turn on. Changed resistor R101. Resistor

R101 was 19B800607P473, 47k Ohms.

REV. H - Transmitter Synthesizer Board 19D902779G1

To decrease the output power by approximately 1.0 dB.

Changed resistor R220. Resistor R220 was

19B800607P220, 22 Ohms.

LBI-38640G

IC DATA

U302 & U601

19A116297P7

Dual Wide Band Op-Amp

U401

19A149944P201

Dual Modulus Prescaler

U501

344A3070P1

Operational Amplifier

U502

19A702705P4

Quad Analog Switch

U702

19A703471P320

Address Decoder

U701 & U705

19A703483P302

Quad 2-Input NAND Gate

U201 & U203

19A705927P11

Silicon Bipolar MMIC

U301

19A704971P9

+5V Regulator

U303

19A704971P7

-5V Regulator

U402

19B800902P5/P7

Synthesizer

LBI-38640G

HARRIS TR-0017-E Sitepro Base Station User Manual TX Synth

HARRIS CORPORATION Sitepro Base Station TX Synth

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