Codan Radio Communications VT-3-150-SN User Manual
2-16
Transmitter Main Board Instruction Manual
2.4.4.9
Audio Processor Direct Modulation Input
The Direct Modulation Input is an extremely versatile input. This port is designed to be used for
data signals. Depending on the application, the signal can be amplified, AC or DC coupled and
output to the Modulation Output or the Low Frequency / Direct Modulation Output port. Please
consult the factory for specific jumper settings for your application.
data signals. Depending on the application, the signal can be amplified, AC or DC coupled and
output to the Modulation Output or the Low Frequency / Direct Modulation Output port. Please
consult the factory for specific jumper settings for your application.
2.5
Low Frequency Modulation
The transmitter has an additional option to address low frequency user modulation requirements. A
phase modulated bandwidth from 0 (dc) to 100 Hz (PLL loop filter bandwidth) allows specialized
applications such as paging or trunking where a separate low frequency digital/analog modulation
channel is required. Low Frequency Modulation allows external access to the low frequency
modulation capabilities of the synthesizer module. The DIRECT MODULATION inputs on the J1
control connector of the M-3 motherboard will be used (B20 for TX A, and A20 for
TX B). See section 3.11, 'Low Frequency Modulation Configuration' for set up and alignment.
phase modulated bandwidth from 0 (dc) to 100 Hz (PLL loop filter bandwidth) allows specialized
applications such as paging or trunking where a separate low frequency digital/analog modulation
channel is required. Low Frequency Modulation allows external access to the low frequency
modulation capabilities of the synthesizer module. The DIRECT MODULATION inputs on the J1
control connector of the M-3 motherboard will be used (B20 for TX A, and A20 for
TX B). See section 3.11, 'Low Frequency Modulation Configuration' for set up and alignment.