108Making Time-Gated MeasurementsGated FFT MeasurementGated FFT MeasurementThis procedure utilizes gated FFT to gate the FM signal. For concept and theoryinformation about gated FFT see “How time gating works” on page 199.Step Action Notes1 Set the analyzer to theSpectrum Analyzer mode.• Press Mode, SpectrumAnalyzer.This enables the spectrum analyzermeasurements.2 Preset the analyzer • Press Mode Preset.3 Set the center frequency,span, reference level andattenuation.a. Press FREQ Channel,Center Freq, 40, MHz.b. Press SPAN X Scale,Span, 500, kHz.c. Press AMPTD Y Scale,Ref Level, 10, dBm.4 Set the Gate source to theexternal trigger input on therear panel.• Press Sweep/Control,Gate, More, GateSource, External 1.5 Set the gate method and turngate on.a. Press Sweep/Control,Gate, Gate Method,FFT.b. Press Gate (On).6 Select the minimumresolution bandwidthrequired.• Press BW, Res BW(Auto).See Figure 8-12.
