DE
DANIELS
ELECTRONICS
MT-3 AM 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
MT-3 AM 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 ................................... 2-5
2.1.5
Amplifier Circuits ........................................................... 2-6
2.2
MT-3 Front Panel Board ............................................................ 2-6
2.3
MT-3 AM Audio Processor......................................................... 2-6
2.3.1
General ....................................................................... 2-6
2.3.2
Power Requirements........................................................ 2-6
2.3.3
Audio Circuitry.............................................................. 2-7
2.3.4
PTT Time-Out-Timer ....................................................... 2-8
3
TRANSMITTER ALIGNMENT............................................................. 3-1
3.1
General ................................................................................ 3-1
3.2
Repair Note ........................................................................... 3-1
3.3
Printed Circuitboard Numbering Convention..................................... 3-1
3.4
Recommended Test Equipment List ............................................... 3-1
3.5
Standard Factory Settings and Jumper Configuration ........................... 3-2
3.5.1
MT-3 AM Transmitter Board Factory Configuration ................... 3-2
3.5.2
MT-3 AM Audio Processor Factory Configuration..................... 3-3
3.6
MT-3 AM Transmitter Board Alignment .......................................... 3-3
