Motorola CDM1250 Service Manual

Section 9: i
6881091C63-F
Section 9: UHF Band 1 (403–470 MHz) 25–40 W Bipolar
Service Information
Table of Contents
Chapter 1 Model Charts and Technical Specifications
1.0 UHF Band 1 (403–470 MHz) 25–40 W Bipolar Model Charts ..........................9:1-1
1.1 CDM Series Model Chart ............................................................................9:1-1
1.2 PRO Series Model Chart.............................................................................9:1-2
2.0 Technical Specifications ...................................................................................9:1-2
Chapter 2 Theory of Operation
1.0 Introduction.......................................................................................................9:2-1
2.0 UHF Band 1 (403–470 MHz) 25–40 W Bipolar Receiver Front-End ................9:2-1
2.1 Receiver Front-End .....................................................................................9:2-1
2.2 Front-End Bandpass Filters and Pre-Amplifier............................................9:2-2
2.3 First Mixer and 1st Intermediate Frequency (IF) .........................................9:2-2
2.4 2nd Intermediate Frequency (IF) and Receiver Back-End..........................9:2-2
3.0 UHF Band 1 (403–470 MHz) 25–40 W Bipolar Transmitter Power Amplifier
(PA) 40W ..........................................................................................................9:2-3
3.1 Power Controlled Stage ..............................................................................9:2-3
3.2 Pre-Driver Stage..........................................................................................9:2-4
3.3 Driver Stage ................................................................................................9:2-4
3.4 Final Stage ..................................................................................................9:2-4
3.5 Bi-directional Coupler..................................................................................9:2-4
3.6 Antenna Switch ...........................................................................................9:2-4
3.7 Harmonic Filter............................................................................................9:2-5
3.8 Power Control..............................................................................................9:2-5
4.0 UHF Band 1 (403–470 MHz) 25–40 W Bipolar Frequency Synthesis..............9:2-5
4.1 Reference Oscillator....................................................................................9:2-5
4.2 Fractional-N Synthesizer.............................................................................9:2-6
4.3 Voltage Controlled Oscillator (VCO)............................................................9:2-7
4.4 Synthesizer Operation.................................................................................9:2-8
Chapter 3 Troubleshooting Charts
1.0 Troubleshooting Flow Chart for Receiver .........................................................9:3-1
2.0 Troubleshooting Flow Chart for 40W Transmitter.............................................9:3-3
3.0 Troubleshooting Flow Chart for Synthesizer.....................................................9:3-4
4.0 Troubleshooting Flow Chart for VCO................................................................9:3-5
5.0 Troubleshooting Flow Chart for PassPort.........................................................9:3-6

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