User's Guide

iv Transmitter Main Board Instruction Manual IM20-MT3TXMN
2.4 Version 2.3 Audio Processor .................................................................................2-15
2.4.1 Introduction......................................................................................................2-15
2.4.2 Version 2.3 FM Audio Processor Block Diagram ...........................................2-17
2.4.3 Factory Configuration......................................................................................2-18
2.4.4 Turn-on Time...................................................................................................2-19
2.4.5 Low Frequency Modulation.............................................................................2-19
2.4.6 Audio Processor Signals..................................................................................2-20
2.4.6.1 FM Audio Processor Outputs......................................................................2-20
2.4.6.2 Audio Processor Modulation Outputs.........................................................2-20
2.4.6.3 Audio Processor Microphone Input.............................................................2-21
2.4.6.4 Audio Processor Balanced Input..................................................................2-21
2.4.6.5 Audio Processor Auxiliary Input.................................................................2-21
2.4.6.6 Audio Processor Subtone Inputs.................................................................2-22
2.4.6.7 Direct Modulation Input..............................................................................2-22
2.4.6.8 Low Frequency Modulation.........................................................................2-22
2.4.7 Audio Processor Signal Paths (Version 2.3)....................................................2-23
3 TRANSMITTER ALIGNMENT .....................................................................................3-1
3.1 General...................................................................................................................3-1
3.2 Repair Note............................................................................................................3-1
3.3 Printed Circuit Board Numbering Convention .......................................................3-1
3.4 Recommended Test Equipment List.......................................................................3-2
3.5 Standard Factory Settings and Jumper Configuration............................................3-2
3.5.1 MT-3 Transmitter Main Board Factory Configuration.....................................3-2
3.6 MT-3 Transmitter Main Board Configuration........................................................3-4
3.6.1 General.............................................................................................................3-4
3.6.2 MT-3 Transmitter Main Board Test Points......................................................3-4
3.7 Module Installation and Removal...........................................................................3-5
3.8 Audio Processor Alignment ...................................................................................3-6
3.8.1 Multiple Channel Transmitters.........................................................................3-7
3.8.2 Audio Processor Version Identification and Adjustment Locations..................3-7
3.8.3 Audio Processor Alignment Procedures...........................................................3-9
3.8.3.1 Transmitters with Pre-Emphasis and CTCSS Subtone................................3-9
3.8.3.2 Transmitters with Flat Audio and CTCSS subtone......................................3-13
4 TROUBLESHOOTING ..................................................................................................4-1
4.1 Balanced Input Test................................................................................................4-1
4.2 Frequency Response Test ......................................................................................4-1
4.3 Subtone Input Test.................................................................................................4-1
5 TEMPERATURE COMPENSATION ............................................................................5-1
6 TRANSMITTER INTERCONNECT PIN DEFINITIONS............................................6-1
7 AUDIO PROCESSOR JUMPER CONFIGURATIONS...............................................7-1
7.1 Version 1.8 Audio Processor Jumper Configuration..............................................7-1
7.2 Version 2.3 Audio Processor Jumper and Select Value Tables ..............................7-3