To Window In On Harmonic Distortion Using Fft - HP 54616B User And Service Manual

Using Option 005 Enhanced TV/Video Trigger

To window in on harmonic distortion using FFT

To window in on harmonic distortion using FFT
Sine waves that are not perfectly shaped in the time domain generate
harmonics in the frequency domain. Viewing this distortion in the time
domain is usually very difficult, unless the waveform is severely distorted.
However, in the frequency domain, these harmonics are very apparent. Your
oscilloscope, when used with the HP 54657A, HP 54658A, or HP 54659B
Measurement/Storage module, have the ability to perform frequency domain
analysis on a time domain waveform using the Fast Fourier Transform (FFT).
A special case of measuring the harmonic distortion in a sine wave is found in
video applications. The 3.58 MHz color-subcarrier frequency embedded in an
NTSC composite video signal has some amount of harmonic distortion
associated with the subcarrier frequency. To measure just this signal, the
scope's time/division and delay controls are used to zoom in on the color
burst in the time domain.
Figure 3-11
The scope controls are used to zoom in on the color burst in the time domain
3–18