User's Manual Part 1

Modulator Module

A/V ratio adjustment:

Adjust the Aural Level potentiometer for the desired A/V ratio for the system.

Fault Indicators:

A PLL: This illuminates when the Aural IF PLL is unlocked.

IF PLL: This illuminates when the IF PLL unlocks.

A MOD: This indicator will illuminate when the audio overdeviates the aural carrier.

V I/P: This indicates the loss of Video to the modulator

V MOD: This illuminates when the video is overmodulated.

Status Indicators:

EXT IF CW: This indicates that there is an external IF CW signal applied to the

modulator10MHz: This indicates the presence of the 10 MHz reference.

The modulator can be used with an external 4.5MHz aural input instead of the normal bal

anced and composite inputs. The 4.5 MHz is applied to the transmitter using the composite

audio input connector. There are three jumpers on the modulator module that will need to be

moved to convert to this input.

Conversion procedure:

Remove modulator module. Move the jumper on J4 so that it connects pins 1 and 2. Move the

jumper on J6 so that it connects pins 1 and 2. Move the jumper on J5 so that it connects pins

2 and 3.

Install modulator module. Apply 4.5 MHz signal to rear of tray to the composite audio input.

This level should be between -14 and -10 dBm. Adjust the “A IF” potentiometer on the modula

tor for the desired A/V ratio for the transmitter.