___________________________________________________________
GNS 400W Series Maintenance Manual
Page 4-31
190-00356-05
Rev. A
Opening Time (25 kHz)
NOTE
Squelch opening time measurements are made manually using an oscilloscope.
1.
Enable the compressor.
2.
Set the channel mode to 25 kHz.
3.
Generate an RF signal with 30% modulation, a modulation frequency of 1,000 Hz, an
RF carrier frequency of 127.000 mHz, and an input level of –53 dBm.
4.
Set the volume for rated output.
5.
Change the RF input level to no signal.
6.
Change the RF input level to –101 dBm (4.0 µV). Observe and capture the
waveform showing the time it takes for the audio output to stabilize (open time).
7.
Change the RF input level to no signal.
8.
Change the RF input level to –53 dBm (1,000 µV). Observe and capture the
waveform showing the time it takes for the audio output to stabilize (open time).
Opening Time (8.33 kHz)
1.
Enable the compressor.
2.
Set the channel mode to 8.33 kHz.
3.
Generate an RF signal with 30% modulation, a modulation frequency of 1,000 Hz, an
RF carrier frequency of 127.000 mHz, and an input level of –53 dBm.
4.
Set the volume for rated output.
5.
Change the RF input level to no signal.
6.
Change the RF input level to –97.4 dBm (6.0 µV). Observe and capture the
waveform showing the time it takes for the audio output to stabilize (open time).
7.
Change the RF input level to no signal.
8.
Change the RF input level to –53 dBm (1,000 µV). Observe and capture the
waveform showing the time it takes for the audio output to stabilize (open time).
Signal Pin
Signal Name
Reference Pin
Reference Name
Load
J2-7
COMM AUDIO HI
J2-19
COMM AUDIO LO
500 Ohms
