Parts List

Transmitter Main Board Instruction Manual iii
TABLE OF CONTENTS
Page
1 GENERAL...................................................................................................................1-1
1.1 Introduction ....................................................................................................1-1
1.2 Performance Specifications .............................................................................1-1
1.2.1 General...............................................................................................1-1
1.2.2 Audio Specifications ...........................................................................1-2
2 THEORY OF OPERATION........................................................................................2-1
2.1 Transmitter Main Board..................................................................................2-1
2.1.1 General...............................................................................................2-1
2.1.2 Transmitter Push-To-Talk...................................................................2-1
2.1.2.1 Microphone PTT ....................................................................2-1
2.1.2.2 PTT With Time-Out-Timer .....................................................2-2
2.1.2.3 PTT No Time-Out-Timer ........................................................2-2
2.1.2.4 Optional Relay........................................................................2-2
2.1.2.5 PTT Output.............................................................................2-3
2.1.2.6 PTT Voltage Switching ...........................................................2-3
2.1.2.7 Transmitter Standby Modes....................................................2-3
2.1.3 Audio Circuits .....................................................................................2-4
2.1.3.1 Microphone Audio ..................................................................2-5
2.1.3.2 Received Audio .......................................................................2-5
2.1.4 Channel Selection ...............................................................................2-5
2.1.4.1 Synthesized Transmitter ..........................................................2-5
2.1.4.2 Crystal Controlled Transmitter ................................................2-6
2.1.5 Amplifier Circuits ...............................................................................2-6
2.1.6 Time-Out-Timer Circuitry ...................................................................2-6
2.2 MT-3 Front Panel Board ................................................................................2-8
2.3 MT-3 Audio Processor (Version 1.6).............................................................2-8
2.3.1 General...............................................................................................2-8
2.3.2 Power Requirements ...........................................................................2-8
2.3.3 Audio Processor Turn-on Time ..........................................................2-9
2.3.4 Audio Processor Signals.....................................................................2-9
2.3.4.1 Audio Processor Outputs........................................................2-9
2.3.4.2 Audio Processor Modulation Output......................................2-10
2.3.4.3 Audio Processor Low Frequency / Direct Mod. Output .........2-10
2.3.4.4 Audio Processor Inputs ..........................................................2-10
2.3.4.5 Audio Processor Microphone Input........................................2-11
2.3.4.6 Audio Processor Balanced Input.............................................2-11
2.3.4.7 Audio Processor Auxiliary Input ............................................2-11
2.3.4.8 Audio Processor Subtone Inputs ............................................2-11
2.3.4.9 Audio Processor Direct Modulation Input..............................2-12
2.4 MT-3 Audio Processor (Version 1.8).............................................................2-12