Tektronix TDS 500C, TDS 600B, TDS 700C - page 258

Using Features for Advanced Applications
TDS 500C, TDS 600B, & TDS 700C User Manual 3–197
Figure 3–95 shows the cursor measurement of a frequency magnitude on an
FFT. The @: readout reads 0 dB because it is aligned with the 1 VRMS level.
The D: readout reads 24.4 dB indicating the magnitude of the frequency it is
measuring is –24.4 dB relative to 1 VRMS. The source waveform is turned
off in the display.
The cursor units will be in dB or volts for FFTs measuring magnitude and in
degrees or radians for those FFTs measuring phase. The cursor unit depends
on the selection made for Set FFT Vert Scale to (side). See step 7 on page
3–194 for more information.
Figure 3–95: Cursor Measurement of an FFT Waveform
6. Press V Bars (side). Use the general purpose knob to align one of the two
vertical cursors to a point of interest along the horizontal axis of the
waveform.
7. Press SELECT to select the alternate cursor.
8. Align the selected cursor to another point of interest on the math waveform.