Technical data

Chapter 5 103
Spectrum Analyzer
Using the Analyzer as a Fixed Tune Receiver
Spectrum Analyzer
and turn AM on.
Step 3. Select the spectrum analyzer mode:
Press
Mode, Spectrum Analyzer.
Step 4. Preset the analyzer.
Press
Mode Preset.
Step 5. Set the center frequency, span, RBW and the sweep time.
Press
FREQ Channel, Center Frequency, 300, MHz.
Press
SPAN X Scale, Span, 500, kHz.
Press
BW, Res BW, 30, kHz.
Step 6. Set the y-axis units to volts:
Press
AMPTD Y Scale, More, Y-Axis Units, Volts.
Step 7. Position the signal peak near the reference level:
Press
AMPTD Y Scale, Ref Level, (rotate front-panel knob).
Step 8. Change the y-scale type to linear:
Press
AMPTD Y Scale, Scale Type (Lin).
Step 9. Set the analyzer in zero span to make time-domain measurements:
Press
SPAN X Scale, Zero Span.
Press
Control/Sweep, Sweep Time, 5, ms.
Step 10. Use the video trigger to stabilize the trace:
Press
Meas Setup, Trigger, Video. Adjust the trigger level for a stable
trace.
Since the modulation is a steady tone, you can use video trigger to
trigger the analyzer sweep on the waveform and stabilize the trace,
much like an oscilloscope. See Figure 5-26.
NOTE If the trigger level is set too high or too low when video trigger mode is
activated, the sweep stops. You need to adjust the trigger level up or
down with the front-panel knob until the sweep begins again.
Step 11. Measure the AM rate using delta markers:
Press
Peak Search, Marker, Delta, Peak Search, Next Pk.
Use markers and delta markers to measure the AM rate. Place the
marker on a peak and then use a delta marker to measure the time