EDACS REPEATERS
2-17
Tx Distortion
Transmitter distortion.
The Tx Distortion test is used to measure the distortion level of the modulated signal from the
repeater.
The test fails if the distortion level is above the prescribed limit.
The Service Monitor AF generator frequency is set to 1 kHz and its level is adjusted until the
repeater generates the nominal modulation level. The Service Monitor then measures the Tx
distortion of the modulated signal of the repeater.
Failure messages are:
*FAIL* ABORTED BY USER User halted program before test was complete.
*FAIL* NO MODULATION No modulation has been received from the
repeater.
*FAIL* UNSTABLE DEMOD
Demodulation was not within 5% after 3 readings or
1% after 10 readings.
Tx S/N
Transmitter S/N
The Tx S/N test measures the signal-to-noise level of the modulated signal from the repeater. The
test fails if the signal-to-noise level is below the prescribed limit.
The Service Monitor AF generator frequency is set to 1 kHz and its level is adjusted until the
repeater generates the nominal modulation level. The Service Monitor then measures the Tx S/N
of the modulated signal of the repeater.
Failure messages are:
*FAIL* ABORTED BY USER User halted program before test was complete.
*FAIL* NO MODULATION No modulation has been received from the
repeater.
*FAIL* UNSTABLE DEMOD
Demodulation was not within 5% after 3 readings or
1% after 10 readings.
*FAIL* UNSTABLE DEMOD Signal-to-noise level is below the prescribed limit.
Tx Noise
Transmitter residual noise.
The Tx Noise test determines the level of 'FM noise' produced by the repeater. The test fails if the
noise level is above the prescribed limit.
The Service Monitor measures the modulation level of the repeater in the absence of a modulating
signal from the Service Monitor.
Failure messages are:
*FAIL* ABORTED BY USER User halted program before test was complete.
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