3.9.3 To display the frequency domain using FFT
The FFT math function mathematically converts a time- domain waveform into its frequency components. FFT waveforms are useful for finding the harmonic content and distortion in systems, for characterizing noise in DC power supplies, for analyzing vibration, for estimating the impulse responses in systems, and for measuring the harmonic in power cords. To display a waveform’s FFT: 1.Press MATH MENU. 2.In the Math menu, press Operation. 3.To select “FFT”. 4. Press Sourcesoftkey to select the desired input channel.
NOTE ? The FFT of a waveform that has a DC component or offset can cause incorrect FFT waveform magnitude values. To minimize the DC component, choose AC Coupling on the source waveform. ? To reduce random noise and aliasing components (in repetitive or single-shot waveforms), set the oscilloscope acquisition mode to averaging.
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