Tektronix TDS5054, Руководство пользователя

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Creating and Using Math Waveforms
TDS5000 Series User Manual
3- 173
Frequency
A
m
plit
ude
Aliased frequencies Actual frequencies
0 Hz
Nyquist frequency
(
½
sample rate)
Figure 3- 58: How aliased frequencies appear in a spectral waveform
If you have a variable-frequency signal source, another way to observe aliasing is
to adjust the frequency slowly while watching the spectral display. If some of the
harmonics are aliased, you will see the harmonics decreasing in frequency when
they should be increasing or vice versa.
To Take Cursor Measurements of a Spectral Math Waveform. Once you have
displayed a spectral math waveform, use cursors to measure its frequency
amplitude or phase angle. Use the procedure found in
Taking Cursor Measure-
ments
on page 3--124.
To Take Automated Measurements of a Spectral Math Waveform. You can use
automated measurements to measure spectral math waveforms. Use the
procedure found in
Taking Automatic Measurements on page 3--115.