Operating instructions

GENERAL INFORMATION
1-4
Receiver testing
Service Monitor
Rx
Under
Test
DEMODULATED AF SIGNAL
MODULATED RF TEST SIGNAL
C3241
Fig. 1-2 Receiver test setup
The receiver test procedure uses:-
The RF generator and the AF generators, to produce a transmission with defined
parameters.
The AF voltmeter, to measure the level of the demodulated signal from the receiver.
The distortion meter, to obtain signal-to-noise ratio, SINAD levels and distortion
percentage figures.
The tone generator and tone detector, to produce and decode specialized calling tones to test
tone recognition circuits.
The oscilloscope, to view and measure the demodulated signal or other waveforms.
The RF signal from the Service Monitor is coupled to the receiver and the demodulated signal
from the receiver taken to the AF input of the Service Monitor. By measuring the levels of the AF
signal from the receiver, the sensitivity of the receiver can be checked. The distortion levels
introduced by the receiver can be measured.
During all of the above procedures, the RF levels, the distortion levels and modulation levels can
be displayed on bar charts as well as being provided as a digital read-out. The AF waveforms can
also be studied using the digital oscilloscope facility.
Duplex testing
Service Monitor
Rx/Tx
Under
Test
DEMODULATED AF SIGNAL
MODULATED
RF TEST
SIGNAL
RF SIGNAL
FROM RADIO
UNDER TEST
AF GENERATOR OUTPUT
C5442
Fig. 1-3 One port duplex test setup