Math FFT
124 TDS1000/2000-Series Digital Oscilloscope User Manual
HIf you do not need to view frequencies component sa bove 20
MHz, set the BandwidthLimit option to On.
HPut an external filter on the sourcesignal to bandwidth limit the
source waveform to frequencies below that of the Nyquist
frequency.
HRecognize and ignore the aliased frequenci es.
HUse zoom controls and the cursors to magnify and mea sure the
FFT spectrum
Magnifying and Positioning an FFT Spectrum
You can magnify and use cursors to take measurements on the FFT
spectrum. The oscilloscopeincludes an FFT Zoom option to magnify
horizontally.To magnify vertically, youcan use the vertical controls.
Horizontal Zoom and Position
The FFT Zoom option lets you horizontall y magnify the FFT
spectrum without changing the sample rate. Zoom fa ctors are X1
(default), X2, X5, and X10. At zoom factor X1, and with the
waveform centered inthe graticule, the left graticule line is at 0 Hz
and the right graticule line is at the Nyquist frequency.