Filter
Top Products
Fast Fourier Transforms
TDS 620A, 640A & 644A User Manual
3Ć37
impulse. The horizontal scale for FFT math waveforms is always expressed
in frequency per division with the beginning (leftĆmost point) of the waveform
representing zero frequency (DC).
The FFT waveform is based on digital signal processing (DSP) of data,
which allows more versatility in measuring the frequency content of waveĆ
forms. For example, DSP allows the oscilloscope to compute FFTs of source
waveforms that must be acquired based on a single trigger, making it useful
for measuring the frequency content of single events.
Normal Waveformof an
Impulse Response
FFT Waveform of the
Magnitude Response
FFT Waveform of the
Phase Response
Figure 3Ć20:ăSystem Response to an Impulse
To obtain an FFT of your waveform:
1. Connect the waveform to the desired channel input and select that
channel.
2. Adjust the vertical and horizontal scales and trigger the display (or press
AUTOSET).
The topic Offset, Position, and Scale, on page 3Ć44, provides in depth
information about optimizing your setup for FFT displays.
3. Press MORE to access the menu for turning on math waveforms.
4. Select a math waveform. Your choices are Math1, Math2,and
Math3 (main).
Operation