Motorola CDM1250 Service Manual

Section 12: i
6881091C63-F
Section 12: UHF Band 1 (403–470 MHz) 25–40 W LDMOS
Service Information
Table of Contents
Chapter 1 Model Charts and Technical Specifications
1.0 UHF Band 1 (403–470 MHz) 25–40 W LDMOS Model Charts.......................12:1-1
1.1 CDM Series Model Chart ..........................................................................12:1-1
1.2 PRO Series Model Chart...........................................................................12:1-2
2.0 Technical Specifications .................................................................................12:1-2
Chapter 2 Theory of Operation
1.0 Introduction.....................................................................................................12:2-1
2.0 UHF Band 1 (403–470 MHz) 25–40 W LDMOS Receiver Front-End.............12:2-1
2.1 Receiver Front-End ...................................................................................12:2-1
2.2 Front-End Bandpass Filters and Pre-Amplifier..........................................12:2-2
2.3 First Mixer and High Intermediate Frequency (IF).....................................12:2-2
2.4 Low Intermediate Frequency (IF) and Receiver Back-End .......................12:2-3
3.0 UHF Band 1 (403–470 MHz) 25–40 W LDMOS Transmitter Power Amplifier
(PA) 40W ........................................................................................................12:2-3
3.1 First Power Controlled Stage ....................................................................12:2-4
3.2 Power Controlled Driver Stage..................................................................12:2-4
3.3 Final Stage ................................................................................................12:2-4
3.4 Directional Coupler....................................................................................12:2-4
3.5 Antenna Switch .........................................................................................12:2-4
3.6 Harmonic Filter..........................................................................................12:2-5
3.7 Power Control............................................................................................12:2-5
4.0 UHF Band 1 (403–470 MHz) 25–40 W LDMOS Frequency Synthesis ..........12:2-5
4.1 Reference Oscillator..................................................................................12:2-6
4.2 Fractional-N Synthesizer...........................................................................12:2-6
4.3 Voltage Controlled Oscillator (VCO)..........................................................12:2-7
4.4 Synthesizer Operation...............................................................................12:2-8
Chapter 3 Troubleshooting Charts
1.0 Troubleshooting Flow Chart for Receiver .......................................................12:3-1
2.0 Troubleshooting Flow Chart for 40 W Transmitter..........................................12:3-3
3.0 Troubleshooting Flow Chart for Synthesizer...................................................12:3-5
4.0 Troubleshooting Flow Chart for VCO..............................................................12:3-6
5.0 Troubleshooting Flow Chart for PassPort.......................................................12:3-7

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