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UHF Band 2 (450–512/520 MHz) 25–40 W LDMOS Transmitter Power Amplifier (PA) 40 W
Section 13: 2-3
20/25 kHz channel spacing, or FL3111 and FL3113/F3115 for 12.5 kHz channel spacing. These
pairs are selectable via BWSELECT. The filtered output from the ceramic filters is applied to the
limiter input pin of the IF IC (pin 14).
The IF IC contains a quadrature detector using a ceramic phase-shift element (Y3102) to provide
audio detection. Internal amplification provides an audio output level of 120 mV rms (at 60%
deviation) from U3103, pin 8 (DISCAUDIO) which is fed to ASFIC_CMP U0221, pin 2 (part of the
controller circuits).
A Receive Signal Strength Indicator (RSSI) signal is available at U3101, pin 5, which has a dynamic
range of 70 dB. The RSSI signal is interpreted by the µP (U0101, pin 63) and is available at
accessory connector J0501-15.
3.0
UHF Band 2 (450–512/520 MHz) 25–40 W LDMOS Transmitter
Power Amplifier (PA) 40 W
The radio’s 40W PA is a three-stage amplifier used to amplify the output from the VCOBIC to the
radio transmit level. All three stages utilize LDMOS technology. The gain of the first stage (U5401) is
adjustable, controlled by pin 4 of PCIC (U5501). It is followed by an LDMOS stage (Q5421) and
LDMOS final stage (Q5441).
Figure 13-2
UHF Transmitter Block Diagram
Devices U5401, Q5421 and Q5441 are surface mounted. A pressure pad between the board and
the radio’s cover provides good thermal contact between the devices and the chassis.
P C I C
Pin Diode
Antenna
Switch
RF Jack
Antenna
Harmonic
Filter
Power
Sense
PA-Final
Stage
PA
Driver
From VCO
Controlled
Stage
Vcontrol
Bias 1
Bias 2
To Microprocessor
Temperature
Sense
SPI BUS
A S F I C _ C M P
PA
PWR
SET
To Microprocessor
& Bias 3
Summary of Contents for PRO Series
Page 1: ...CDM Series and PRO Series Two Way Mobile Radios Detailed Service Manual 6881091C63 F ...
Page 4: ...Notes ...
Page 6: ...Notes ...
Page 8: ...Section 1 ii 6881091C63 F Notes ...
Page 12: ...Section 1 1 4 Radio Model Information 6881091C63 F Notes ...
Page 22: ...Section 1 2 10 Notes For All Schematics and Circuit Boards 6881091C63 F Notes ...
Page 46: ...Section 2 4 2 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 78: ...Section 3 1 20 Controller Board Audio and Signaling Circuits Section 6881091C63 F Notes ...
Page 80: ...Section 3 2 2 Troubleshooting Flow Chart for Controller 6881091C63 F Notes ...
Page 84: ...Section 3 3 4 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 146: ...Section 3 3 66 Controller T6 T7 Schematics and Parts Lists 8471235L06 Notes 6881091C63 F ...
Page 152: ...Section 4 1 4 Technical Specifications 6881091C63 F Notes ...
Page 168: ...Section 4 3 8 Troubleshooting Flow Chart for VCO 6881091C63 F Notes ...
Page 172: ...Section 4 4 4 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 232: ...Section 5 1 4 Technical Specifications 6881091C63 F Notes ...
Page 242: ...Section 5 2 10 UHF Band 1 403 470 MHz 1 25 W Frequency Synthesis 6881091C63 F Notes ...
Page 296: ...Section 6 1 4 Technical Specifications 6881091C63 F Notes ...
Page 306: ...Section 6 2 10 UHF Band 2 450 512 527 MHz 1 25 W Frequency Synthesis 6881091C63 F Notes ...
Page 316: ...Section 6 4 2 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 352: ...Section 7 3 6 Troubleshooting Flow Chart for VCO 6881091C63 F Notes ...
Page 356: ...Section 7 4 4 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 458: ...Section 8 1 4 Technical Specifications Section 6881091C63 F Notes ...
Page 474: ...Section 8 4 2 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 496: ...Section 9 1 4 Technical Specifications Section 6881091C63 F Notes ...
Page 512: ...Section 9 4 2 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 530: ...Section 10 1 4 Technical Specifications Section 6881091C63 F Notes ...
Page 546: ...Section 10 4 2 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 564: ...Section 11 1 4 Technical Specifications 6881091C63 F Notes ...
Page 580: ...Section 11 3 8 Troubleshooting Flow Chart for VCO 6881091C63 F Notes ...
Page 582: ...Section 11 4 2 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 608: ...Section 12 1 4 Technical Specifications 6881091C63 F Notes ...
Page 624: ...Section 12 3 8 Troubleshooting Flow Chart for PassPort 6881091C63 F Notes ...
Page 626: ...Section 12 4 2 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...
Page 654: ...Section 13 1 4 Technical Specifications 6881091C63 F Notes ...
Page 672: ...Section 13 4 2 Allocation of Schematics and Circuit Boards 6881091C63 F Notes ...