Operating instructions

LOCAL OPERATION
3-61
The Span setting controls the sweep range covered by the spectrum analyzer. When in the Look
and Listen mode the sweep span is selected from the Span menu accessible by pressing the [Span]
key. Four span widths are available as listed below.
1 MHz 500 kHz 200 kHz 100 kHz
Demod settings
The ‘listen’ demodulator and its associated circuits are set to extract the information from the
signal tuned to the center frequency of the display. The following options are available through
the [Demod] key.
Modulation type
AM FM
De-emphasis
ON OFF
AF filter
300 Hz to
3.4 kHz
15 kHz LP
'Listen' IF bandwidth
The 'Listen' IF bandwidth for the 'Look & Listen' facility can be set to 15 kHz or 300 kHz. This is
irrespective of the spectrum analyzer resolution bandwidth selected. The current setting is shown
to the left of the display. To change the setting, first press the [Listen IF BW] key, which will
display [15kHz] and [300kHz] keys. Press the appropriate key to select the required setting.
Switching to the Tx TEST mode after a signal has been located will allow the signal to be
monitored with the IF bandwidth set to 300 Hz, 3.0 kHz, 30 kHz or 300 kHz.
Resolution bandwidth selection
The resolution bandwidth for the display can be selected from the following through the [Res BW]
key:-
Auto
Res BW
3 kHz 30 kHz 300 kHz
With automatic resolution bandwidth selected, the resolution bandwidth is dependent on the sweep
span, as shown below:-
Span Setting Resolution Bandwidth
1 MHz 30 kHz
500 kHz 30 kHz
200 kHz 3 kHz
100 kHz 3 kHz
When operating in the Look and Listen mode, some functions or options of SPEC ANA mode will
be available to the user. Reference to these is made on the display but their condition cannot be
changed without returning to the main spectrum analyzer display. These are:-
Reference level dB/div
2 dB 10 dB
Video filter option
OFF ON
Peak hold option
OFF ON