140Demodulating AM SignalsMeasuring the Modulation Rate of an AM SignalMeasuring the Modulation Rate of an AM SignalThis section demonstrates how to determine parameters of an AM signal, such asmodulation rate and modulation index (depth) by using frequency and time domainmeasurements (see the concepts chapter “AM and FM Demodulation Concepts” onpage 215 for more information).To obtain an AM signal, you can either connect a source transmitting an AM signal,or connect an antenna to the analyzer input and tune to a commercial AM broadcaststation. For this demonstration an RF source is used to generate an AM signal.Step Action Notes1 Set up the signalsource.a. Set the source frequency to300 MHz.b. Set the source amplitudes to−10 dBm.c. Set the AM depth to 80%.d. Set the AM rate to 1 kHz.e. Turn AM on.2 Connect an KeysightESG RF signal sourceto the analyzer RFINPUT as shown.3 Select the mode. • Press Mode, SpectrumAnalyzer.4 Preset the analyzer. • Press Mode Preset.
