Operating instructions

LOCAL OPERATION
3-22 46882-311D
When ‘SSB’ demodulation has been selected, the RF sensitivity of the Service Monitor can be
controlled manually. Three sensitivity settings are given as soft key choices; high, medium and
low. The approximate sensitivities of these are shown in the following table:-
[High Sens]
−
90 dBm to
−
30 dBm at ‘N type’
−
110 dBm to
−
50 dBm at ‘Antenna’
[Med Sens]
−
30 dBm to
+
20 dBm at ‘N Type’
−
50 dBm to 0 dBm at ‘Antenna’
[Low Sens]
+
20 dBm to
+
50 dBm at ‘N Type’
0 dBm to
+
30 dBm at ‘Antenna’
Hot surfaces
Take care when touching the RF Input Type N connector after the application of high levels of
continuous power. If 50 W is applied for a prolonged period, the temperature of the connector
can become excessive.
IF bandwidth
The IF bandwidth of the Service Monitor receiver circuits can be selected from the following
options:-
300 Hz 3.0 kHz 30 kHz 300 kHz
Press the [IF Filter] key. The right hand soft keys change, to allow selection of IF bandwidth
filters as shown above.
The selected filter is shown on the display. Press the [Return] key after selecting the required
filter.
Audio frequency filtering
The demodulated signal can be filtered using the following audio filters:-
0.3 - 3.4 kHz
band pass
50 kHz
low pass
15 kHz
low pass
300 Hz
low pass
CCITT
†
or
C-MESS
‡
†
Only if option 23 (CCITT filter) is fitted.
‡
Only if option 24 (C-MESS filter) is fitted.
Press the [AF Filter] key. The right hand soft keys change, to allow selection of AF filters as
shown above. Press the [Return] key after selecting the required filter.
*OSCILLOSCOPE*
The input to the oscilloscope is taken from the demodulators through any selected AF filters.
Therefore modulation measurements made using the oscilloscope will include the characteristics
of the selected AF filter.
WARNING