Operating instructions

LOCAL OPERATION
3-62
Input sensitivity
The input sensitivity of the Service Monitor in the Look and Listen
mode is the same as for the
normal spectrum analyzer input. The reference level can be set using the data input keys, or
adjusted using the variable control. The LEVEL [×] and [Ø] keys adjust the reference level in
either 2 dB or 10 dB steps depending on the setting of the reference level vertical range.
Making measurements
The monitor can be used to determine the frequency of a transmission and to identify the
modulation type and content of asymmetric transmissions. When the transmission to be examined
is visible on the display, adjust the center frequency line on the display to coincide with the peak
of the signal. This will be the carrier frequency and will be shown as a digital readout.
Progressively reduce the span and optimize the filtering and demodulation method while listening
to the demodulated output. As the span is reduced the center frequency may need optimizing.
The peak level of the signal can be determined by reference to the RF level scale on the display.
The top of the graticule represents the reference set on the display. Each division of the graticule
represents either 10 dB or 2 dB, as set in the vertical scale setup menu of the main SPEC ANA
mode.