User`s guide

Math Waveforms 4
Agilent InfiniiVision 2000 X-Series Oscilloscopes User's Guide 67
See Also • "Units for Math Waveforms" on page 74
FFT Measurement
FFT is used to compute the fast Fourier transform using analog input
channels or an arithmetic operation g(t). FFT takes the digitized time
record of the specified source and transforms it to the frequency domain.
When the FFT function is selected, the FFT spectrum is plotted on the
oscilloscope display as magnitude in dBV versus frequency. The readout
for the horizontal axis changes from time to frequency (Hertz) and the
vertical readout changes from volts to dB.
Use the FFT function to find crosstalk problems, to find distortion
problems in analog waveforms caused by amplifier non- linearity, or for
adjusting analog filters.
To display a FFT waveform:
1 Press the [Math] key, press the Function softkey and select f(t), press the
Operator softkey and select FFT.
Figure 6 Example of Subtract Channel 2 from Channel 1