Motorola Radius CM200 Service Manual page 221

Table of Contents
Chapter 1 MODEL CHART AND TECHNICAL SPECIFICATIONS
1.0 CM200/CM300/PM400 Model Chart....................................................................1-1
2.0 Technical Specifications ......................................................................................1-2
Chapter 2 THEORY OF OPERATION
1.0 Introduction ..........................................................................................................2-1
2.0 VHF (146-174 MHz) Receiver.............................................................................2-1
2.1 Receiver Front-End......................................................................................2-1
2.2 Receiver Back End ......................................................................................2-2
3.0 VHF Transmitter Power Amplifier (146-174 MHz)...............................................2-2
3.1 First Power Controller Stage........................................................................2-2
3.2 Power Controlled Driver Stage ....................................................................2-3
3.3 Final Stage...................................................................................................2-3
3.4 Bi-Directional Coupler ..................................................................................2-3
3.5 Antenna Switch............................................................................................2-3
3.6 Harmonic Filter ............................................................................................2-4
3.7 Power Control ..............................................................................................2-4
4.0 VHF (146-174 MHz) Frequency Synthesis .........................................................2-4
4.1 Reference Oscillator ....................................................................................2-4
4.2 Fractional-N Synthesizer .............................................................................2-5
4.3 Voltage Controlled Oscillator (VCO) ............................................................2-6
4.4 Synthesizer Operation .................................................................................2-7
5.0 Controller Theory of Operation ............................................................................2-8
5.1 Radio Power Distribution .............................................................................2-8
5.2 Protection Devices .....................................................................................2-10
5.3 Automatic On/Off .......................................................................................2-10
5.4 Microprocessor Clock Synthesiser ............................................................2-11
5.5 Serial Peripheral Interface (SPI) ................................................................2-12
5.6 SBEP Serial Interface ................................................................................2-12
5.7 General Purpose Input/Output ...................................................................2-12
5.8 Normal Microprocessor Operation .............................................................2-13
5.9 Static Random Access Memory (SRAM) ...................................................2-14
6.0 Control Board Audio and Signalling Circuits ......................................................2-14
6.1 Audio Signalling Filter IC and Compander (ASFIC CMP)..........................2-14
7.0 Transmit Audio Circuits......................................................................................2-15
7.1 Microphone Input Path...............................................................................2-15
7.2 PTT Sensing and TX Audio Processing ....................................................2-16
8.0 Transmit Signalling Circuits ...............................................................................2-17
8.1 Sub-Audio Data (PL/DPL)..........................................................................2-17
8.2 High Speed Data .......................................................................................2-18
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