LOCAL OPERATION
3-27
Tx power
The [Tx Power] key gives access to RF power measurement functions or associated functions.
Broad Band or Narrow Band power
The [Broad/Narrow] key selects which of the RF power measurement methods is operative. The
selected method is indicated on the display by the letters BB or NB to the right of the digital power
reading. The use of this facility is explained under Making measurements later in this chapter.
See page 3-32.
Modulation meter, demodulation options setup
Set up the demodulation options to be compatible with the transmission from the unit under test.
Press the [Mod Meter] key. The soft keys change to the demod soft keys shown in fold out
diagram (2-3).
Modulation Type
The Service Monitor can demodulate AM and FM signals. The demodulated signal is made
available at the ‘DEMOD OUT’ connector on the rear of the instrument. SSB signals can be
demodulated if the SSB option is fitted.
The [AM/FM] key, or [AM/FM/SSB] key, is used to select the appropriate modulation type by
sequential key presses. The
MOD LEVEL indication within the main display becomes suffixed by
% for AM; and by MHz or kHz for FM. When SSB has been selected, no modulation level is
shown, either digitally or as a bar chart.
Selecting the modulation type for Tx TEST does not change the current modulation type set on the
Service Monitor RF generator.
SSB Input sensitivity
No RF carrier signal is produced by SSB transmitters. Therefore the automatic gain control
circuits of the Service Monitor cannot respond to these signals.
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.
WARNING
To Next Page
Loading...
