HARRIS TR-0017-E Sitepro Base Station User Manual

HARRIS CORPORATION Sitepro Base Station Applications Diagrams

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Maintenance ManualLBI-38640GVHF TRANSMITTER SYNTHESIZER MODULE 19D902780G1TABLE OF CONTENTS PageDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Front CoverGENERAL SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1CIRCUIT ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1VOLTAGE CONTROLLED OSCILLATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1RF AMPLIFIERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1REFERENCE BUFFER AMPLIFIER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2PRESCALER AND SYNTHESIZER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2LOOP BUFFER AMPLIFIERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2AUDIO FREQUENCY AMPLIFIER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2VOLTAGE REGULATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 LOGIC CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2TEST PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2ALIGNMENT PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3OUTLINE DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4ASSEMBLY DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5SCHEMATIC DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9PRODUCTION CHANGES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10IC DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11DESCRIPTIONThe principle function of the Transmitter SynthesizerModule is to provide the RF excitation for input to theMASTR 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 functionalblocks:•A voltage controlled oscillator.•A chain of integrated circuit RF Amplifiers. •A reference buffer amplifier.•Dual modulus prescaler and synthesizer integratedcircuits.•Loop amplifiers and passive loop filter.•An audio amplifier and a pre-modulation integrator.•IC voltage regulators for +5 and -5 Vdc. A discretecomponent 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 Systems3315 Old Forest RoadLynchburg, Virginia 24501(Outside USA, 434-385-2400) Toll Free 800-528-7711www.macom-wireless.com Printed in U.S.A.
Copyright © 1992-2002, M/A-COM Private Radio Systems, Inc. All rights reserved.Table 1 - General SpecificationsITEM SPECIFICATIONFREQUENCY RANGE 136 to 174 MHzin 4 bands 136 to 144 MHz142 to 152 MHz150 to 162 MHz160 to 174MHzRF POWER OUT(50 Ohm load) 10 to 13 dBm (10 to 20 mW)RF HARMONICS <-30 dBcNON-HARMONIC SPURS 1 to 200 MHz <-90 dBc 200 MHz to 1 GHz <-60 dBcCARRIER ATTACK TIME <50 msREFERENCE INPUTinput level 0 dBm ±1.5dBinput impedance 50 Ohmfrequency 5 to 17.925 MHz (must be integer divisible bychannel spacing)MODULATION SENSITIVITY 5 kHz peak dev/1 VrmsAF INPUT IMPEDANCE 600 Ohm AF RESPONSE10 Hz ±1.5 dB1000 Hz 0 dB reference3 kHz ±1.5 dB10 Hz SQUARE WAVE MODULATION <10%Sq wave droopHUM & NOISE -55 dBPOWER REQUIREMENTS 13.8 Vdc @ 275 mA-12.0 Vdc@ 10 mACIRCUIT ANALYSISVOLTAGE CONTROLLED OSCILLATORTransistor Q1 and associated circuitry comprise a low noiseVoltage Controlled Oscillator (VCO). Inductor L1 and associ-ated capacitors form the oscillator resonant circuit (tank). Thenoise characteristic of this oscillator is dependent on the Q ofthis resonant circuit. The components used in the tank arespecified to have especially high Q. Diode D1 aids in settingthe bias point for low noise operation. (Any field replacementof oscillator parts should use identical parts).Switches SWIA, SWIB, SWIC and SWID set the fixedcapacitance in the tank and therefore set the frequency rangeover which the oscillator can be voltage tuned. Table 2 showsthe switch settings for the various frequency ranges.Switches SW1E (SW#5) and SW1F (SW#6) also set thefixed capacitance in the tank and perform the frequencytrimming function. These two switches are factory set andshould not need resetting unless any oscillator componentsare changed. (See alignment procedure section of this man-ual for instructions on resetting SW1E and SW1F).The oscillator frequency is voltage tuned by the signalapplied through R5 and L5 to the two varicap diodes D2 andD3. Additionally, audio modulation is applied as an AFvoltage to the two varicap diodes. This AF voltage varies theoscillator frequency at an audio rate (i.e., it frequency modu-lates the oscillator). Low frequency audio is applied alongwith the varicap control voltage through R5 and L5 whilehigh frequency audio (MOD) is applied via C16. Resistors R6 through R9 provide a two volt negative biason the varicap diodes.Figure 1 - Block DiagramTransistors Q101 and Q102 and associated circuitry formthe oscillator enable switch. This switch allows the stationcontrol circuitry to turn the VCO ON or OFF via theANT_REL line. Setting the ANT_REL line to a logic lowcauses Q102 to conduct. The five (5) volt output at Q102collector (OSCON) enables the fault indicator gates, U705Cand 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 amplifiersserve two purposes; amplifying the RF signal for input to thepower amplifier and providing a signal to the Phase-LockedLoop (PLL) . Integrated circuits U201, U203 and transistor Q201provide amplification for the RF signal which will be fed tothe station power amplifier. U201 operates with a gain ofabout 5 dB. Its output is fed to a resistive signal splittercomposed 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 gainof about 6 dB. This amplifier is followed by a 190 MHzcutoff low -pass filter (C216, C217, L203 and L204) and a 6dB resistive attenuator (R219 through R221). The final out-put at the front panel BNC connector (J2) is nominally 11.5dBm into a 50 ohm load.Table 2 - Frequency Range Switch SettingsFREQUENCYRANGE (MHz) SW1A (SW#1) SW1B(SW#2) SW1C(SW#3) SW1D(SW#4)160-174 OPEN OPEN OPEN OPEN150-162 CLOSED OPEN CLOSED OPEN142-152 OPEN CLOSED OPEN CLOSED136-143 CLOSED CLOSED CLOSED CLOSEDLBI-38640G1
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Document ID311105
Application ID075vpy9BfOZpg8rQ7aTVIQ==
Document DescriptionTX Synth
Short Term ConfidentialNo
Permanent ConfidentialNo
SupercedeNo
Document TypeUser Manual
Display FormatAdobe Acrobat PDF - pdf
Filesize35.54kB (444294 bits)
Date Submitted2003-03-18 00:00:00
Date Available2003-03-07 00:00:00
Creation Date2002-03-06 13:42:58
Producing SoftwareAcrobat Distiller 4.05 for Windows
Document Lastmod2003-03-03 18:12:22
Document TitleLBI-38640G, VHF TRANSMITTER SYNTHESIZER MODULE, 19D902780G1
Document Author: M/A-COM Private Radio Systems, Inc.
FCC ID Filing: OWDTR-0017-E

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