Parts List

3-8 Transmitter Main Board Instruction Manual
17 Apply a 1 kHz tone at -8 dBm to the microphone audio input. Set the microphone
compression control (R8) to produce ±60% maximum deviation. Reduce the signal
to -10 dBm and adjust the microphone input level control (R2) for ±50% maximum
deviation. Remove the signal.
18. Apply a 100 Hz tone at -18 dBm to the subtone 1 input and adjust the subtone 1 level
control (R42) to produce ±500 Hz deviation. Remove the signal.
3.9 Standard Factory Settings and Jumper Configuration
Standard factory settings and the associated jumper configuration for the MT-3 Audio Processor
(Version 1.8) are given below.
3.9.1 MT-3 Audio Processor Factory Configuration (Version 1.8)
The MT-3 Audio Processor is factory configured as follows:
• Maximum Deviation: ±2.5 kHz (12.5 kHz or 15 kHz channel),
±5.0 kHz (25 kHz or 30 kHz channel).
• Microphone Input: 1 kHz signal at -10 dBm gives ±50% maximum deviation,
1 kHz signal compression set at ±60% maximum deviation.
• Audio Balanced Input: Enabled - pre-emphasis response,
1 kHz tone at -8 dBm gives ±60% maximum deviation.
1 kHz signal compression set at ±60% maximum deviation.
• Subtone Input 1: 100 Hz tone at -18 dBm gives ±500 Hz deviation.
• All other audio inputs:Disabled.
• Time-Out-Timer: 5 minutes ± 30 seconds.
The corresponding Audio Processor jumper settings are:
• Jumper JU1: not installed Power source select for Direct Modulation circuits.
• Jumper JU2: not installed MT-2 deviation enable (MT-2 transmitters).
• Jumper JU3: 'y' position Microphone preamplifier flat response.
• Jumper JU4: not installed Subtone input 2 audio path select.
• Jumper JU5: not installed Auxiliary input enable (DC or AC coupled).
• Jumper JU6: installed Processed audio path enable (limited and filtered).
• Jumper JU7: not installed Unprocessed auxiliary audio path enable (unfiltered).
• Jumper JU8: not installed Audio output DC coupled (MT-2 transmitters).
• Jumper JU9: installed Balanced input preemphasis response enable.