FM540 Service Manual
Contents
1.Overview ......................................................................................................................................................1
1.1. Scope.......................................................................................................................................................................1
1.2. Safety Precaution...................................................................................................................................................1
2.External Views and Key Features .............................................................................................................2
2.1 Front Panel..............................................................................................................................................................2
2.2 LCD Display............................................................................................................................................................3
2.3 Rear Panel...............................................................................................................................................................4
2.4 Microphone (Handheld).........................................................................................................................................4
3.Circuit Description......................................................................................................................................6
3.1 Overview..................................................................................................................................................................6
3.2 Frequency Composition of Circuit........................................................................................................................6
3.3 RX Principle.............................................................................................................................................................7
3.4 TX Principle.............................................................................................................................................................8
3.5 Principle of Frequency Synthesizer.....................................................................................................................9
3.6 Audio Processing Circuit.....................................................................................................................................10
3.7 Power Supply........................................................................................................................................................10
3.8 MCU Unit...............................................................................................................................................................11
3.9 Semiconductor Description.................................................................................................................................13
4.Feature Description and Parameter Settings ........................................................................................19
4.1 TOT(time-out-timer) .............................................................................................................................................19
4.2 Channel Scan .......................................................................................................................................................19
4.2.1. Carrier Control Scan............................................................................................................................19
4.2.2. Scan Revert Channel..........................................................................................................................20
4.3 Kill and Unkill.........................................................................................................................................................20
4.4 Emergency............................................................................................................................................................20
4.5 Feature and Parameter Settings........................................................................................................................21
5.Assembling and Disassembling..............................................................................................................22
5.1 Exploded View......................................................................................................................................................22
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