DE
DANIELS
ELECTRONICS
2-4
MT-3 AM Transmitter Main Board Instruction Manual
•MODE 1:
Jumper J6 out
- the audio processor is switched by a PTT signal
- the synthesizer or crystal module is switched by a PTT signal
- standby current:
Synthesized - typically 13 mA
Crystal Controlled - typically 6 mA
- start-up time: Synthesized - typically 40 ms
Crystal Controlled - typically 40 ms
•MODE 2:
Jumper J6 in, jumper J7 in the 'y' position, jumper J18 in the 'x' position
- the audio processor is switched by a PTT signal
- the synthesizer or crystal module is enabled all of the time
- standby current:
Synthesized - not used in this mode
Crystal Controlled - typically 6 mA
- start-up time: Synthesized - not used in this mode
Crystal Controlled - typically 40 ms
• MODE 3:
Jumper J6 in, jumper J7 in the 'x' position, jumper J18 in the 'y' position
- the audio processor is enabled all of the time
- the synthesizer or crystal module is switched by a PTT signal
- standby current:
Synthesized - typically 19 mA
Crystal Controlled - typically 11 mA
- start-up time: Synthesized - typically 40 ms
Crystal Controlled - typically 8 ms
•MODE 4:
Jumper J6 in, jumper J7 in the 'x' position, jumper J18 in the 'x' position
- the audio processor is enabled all of the time
- the synthesizer or crystal module is enabled all of the time
- standby current:
Synthesized - typically 163 mA
Crystal Controlled - typically 23 mA
- start-up time: Synthesized - typically 12 ms
Crystal Controlled - typically 8 ms
2 . 1 . 3
Audio Circuits
All of the audio signal conditioning (e.g. limiting, filtering) is performed by the MT-3 AM Audio
Processor. The transmitter board routes the audio lines from the backplane connector to the audio
processor. The audio lines routed to the audio processor are: a 600 ohm balanced input (pins B18
and Z18), and a MIC AUDIO from the MT-3 FRONT PANEL BOARD. It is here that the MIC
audio is processed in the same manner as the 600 ohm balanced audio.
The audio processor's balanced input pins are isolated from pins B18 and Z18 by a transformer
(T1). Two audio outputs from the MT-3 AM Audio Processor are routed to the VT-3A130
Amplifier.
