Motorola CDM1250 Service Manual

Section 13: i
6881091C63-F
Section 13: UHF Band 2 (450–512/520 MHz) 25–40 W
LDMOS Service Information
Table of Contents
Chapter 1 Model Charts and Technical Specifications
1.0 UHF Band 2 (450–512/520 MHz) 25–40 W LDMOS Model Charts................13:1-1
1.1 CDM Series Model Chart ..........................................................................13:1-1
1.2 PRO Series Model Chart...........................................................................13:1-2
2.0 Technical Specifications .................................................................................13:1-2
Chapter 2 Theory of Operation
1.0 Introduction.....................................................................................................13:2-1
2.0 UHF Band 2 (450–512/520 MHz) 25–40 W LDMOS Receiver Front-End......13:2-1
2.1 Receiver Front-End ...................................................................................13:2-1
2.2 Front-End Bandpass Filters and Pre-Amplifier..........................................13:2-2
2.3 First Mixer and High Intermediate Frequency (IF).....................................13:2-2
2.4 Low Intermediate Frequency (IF) and Receiver Back-End .......................13:2-2
3.0 UHF Band 2 (450–512/520 MHz) 25–40 W LDMOS Transmitter Power
Amplifier (PA) 40 W ........................................................................................13:2-3
3.1 First Power Controlled Stage ....................................................................13:2-4
3.2 Power Controlled Driver Stage..................................................................13:2-4
3.3 Final Stage ................................................................................................13:2-4
3.4 Directional Coupler....................................................................................13:2-4
3.5 Antenna Switch .........................................................................................13:2-5
3.6 Harmonic Filter..........................................................................................13:2-5
3.7 Power Control............................................................................................13:2-5
4.0 UHF Band 2 (450–512/520 MHz) 25–40 W LDMOS Frequency Synthesis ...13:2-6
4.1 Reference Oscillator..................................................................................13:2-6
4.2 Fractional-N Synthesizer...........................................................................13:2-6
4.3 Voltage Controlled Oscillator (VCO)..........................................................13:2-7
4.4 Synthesizer Operation...............................................................................13:2-8
Chapter 3 Troubleshooting Charts
1.0 Troubleshooting Flow Chart for Receiver .......................................................13:3-1
2.0 Troubleshooting Flow Chart for 40 W Transmitter..........................................13:3-3
3.0 Troubleshooting Flow Chart for Synthesizer...................................................13:3-4
4.0 Troubleshooting Flow Chart for VCO..............................................................13:3-5
5.0 Troubleshooting Flow Chart for PassPort.......................................................13:3-6

Motorola CDM1250 Specifications

General

Display	Alphanumeric
IP Rating	IP54
Frequency Range	VHF: 136-174 MHz, UHF: 403-470 MHz
Signaling	PL, DPL, MDC1200, Quick Call II
Operating Temperature	-22°F to +140°F (-30°C to +60°C)
Power Output	VHF: 1-25W; UHF: 1-25W