Keysight Technologies N9321C, User Manual

Page: 93 / 220

85
Functions and Measurements
Demodulate the AM/FM signal
Demodulating an FM Signal
This section demonstrates how to demodulate and listen to an FM
signal using the built-in FM demodulator.
Using the built in FM demodulator you can tune to an FM signal
and view the results of the detector output as displayed in the
time-domain.
1 Press
Preset
. (With
Preset Type
of
DFT
)
2 Use a signal source or connect an antenna to recieve FM signal. In
this example the signal is modulated at 300 MHz with FM deviation
of 10 kHz and FM rate of 1 kHz.
3 Set the center frequency to the center of the FM signal (in this case
300 MHz):
Press
Frequency > 300 > MHz
.
4 Set the analyzer to zero span for time-domain analysis:
Press
Span > Zero Span
.
Press
Sweep > Sweep Time > 5 > s
.
5 Set the resolution bandwidth to capture the full bandwidth of the
FM signal.
Press
BW > 100 > kHz
.
6 Turn on the optional pre-amplifier to detect small signals:
Press
Amplitude > Preamp On
.
7 Turn on the FM demodulator:
Press
Marker > Function > Demod
Press
Demod Setting > Demod Type FM
NOTE
If you are using a broadcast FM signal, the FM channels are broadcasting
between 87.7 MHz to 107.7 MHz.