Using Features for Advanced Applications
3–148 TDS 684A, TDS 744A, & TDS 784A User Manual
Hamming — Very good window for resolving frequencies that are very
close to the same value with somewhat improved amplitude accuracy over
the rectangular window.
Hanning — Very good window for measuring amplitude accuracy but
degraded for resolving frequencies.
Blackman-Harris — Best window for measuring the amplitude of
frequencies but worst at resolving frequencies.
The topic Selecting a Window, on page 3–158, provides in depth information
on choosing the right window for your application.
9. If you did not select Phase (deg) or Phase (rad) in step 7, skip to step 12.
Phase suppression is only used to reduce noise in phase FFTs.
10. If you need to reduce the effect of noise in your phase FFT, press Suppress
phase at amplitudes < (side).
11. Use the general purpose knob to adjust the phase suppression level. FFT
magnitudes below this level will have their phase set to zero.
The topic Adjust Phase Suppression, on page 3–157, provides additional
information on phase suppression.
12. Press OK Create Math Wfm (side) to display the FFT of the waveform you
input in step 1. (See Figure 3–88.)
Figure 3–88: FFT Math Waveform in Math1