Motorola GM Series

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Table of Contents
Chapter 1 MODEL CHART AND TECHNICAL SPECIFICATIONS
1.0 GM140/GM160 Model Chart................................................................................1-1
2.0 GM340/GM360/GM380 Model Chart...................................................................1-1
3.0 GM640/GM660/GM1280 Model Chart.................................................................1-2
4.0 Technical Specifications ......................................................................................1-3
Chapter 2 THEORY OF OPERATION
1.0 Introduction ..........................................................................................................2-1
2.0 VHF (136-174MHz) Receiver...............................................................................2-1
2.1 Receiver Front-End ........................................................................................2-1
2.1 Front-End Band-Pass Filters & Pre-Amplifier .................................................2-2
2.2 First Mixer and High Intermediate Frequency (IF)..........................................2-2
2.3 Low Intermediate Frequency (IF) and Receiver Back End.............................2-2
3.0 VHF (136-174MHz)
Transmitter Power Amplifier (PA) 25 W......................2-3
3.1 First Power Controlled Stage..........................................................................2-3
3.2 Power Controlled Driver Stage .......................................................................2-4
3.3 Final Stage .....................................................................................................2-4
3.4 Directional Coupler.........................................................................................2-4
3.5 Antenna Switch...............................................................................................2-5
3.6 Harmonic Filter...............................................................................................2-5
3.7 Power Control.................................................................................................2-5
4.0 VHF (136-174MHz) Frequency Synthesis ...........................................................2-6
4.1 Reference Oscillator.......................................................................................2-6
4.2 Fractional-N Synthesizer ................................................................................2-6
4.3 Voltage Controlled Oscillator (VCO)...............................................................2-7
4.4 Synthesizer Operation....................................................................................2-8
5.0 VHF (136-174MHz)
Transmitter Power Amplifier (PA) 45 W.....................2-9
5.1 Power Controlled Stage..................................................................................2-9
5.2 Pre-Driver Stage...........................................................................................2-10
5.3 Driver Stage..................................................................................................2-10
5.4 Final Stage ...................................................................................................2-10
5.5 Directional Coupler.......................................................................................2-10
5.6 Antenna Switch.............................................................................................2-11
5.7 Harmonic Filter.............................................................................................2-11
5.8 Power Control...............................................................................................2-11