Tait T830 Series, Service Manual

Page: 136 / 284

31/01/96 Copyright TEL
3.8.5.2 Compressor On Microphone Input Only
Open the key line and plug a microphone jack into the front panel socket.
Adjust RV104 (compression level) fully clockwise.
Acoustically couple the microphone to a tone box (1kHz) and close the PTT
switch.
Increase the audio level until the demodulated waveform shows significant signs
of clipping (approximately 4.5kHz [2.3kHz] deviation).
Adjust RV104 (compression level) anticlockwise until the demodulated waveform
is just clipping (approximately 4kHz [2kHz] deviation).
Increase the audio level by 10dB and verify that the test tone is held just into clip-
ping.
Whistle steadily into the microphone, checking that approximately 4kHz [2kHz]
deviation is produced. The modulated waveform should be basically sinusoidal.
Speak into the microphone, checking that the modulation peaks reach about 5kHz
[2.5kHz] deviation.
As the line is to be used without compression, set the line sensitivity (RV100) as
described in Section 3.8.4.
3.8.5.3 Compressor On Both Line & Microphone Inputs
Set up as described in Section 3.8.5.1.