Tektronix TDS 420A - Page 80

Fast Fourier Transforms
TDS 420A, TDS 430A, TDS 460A & TDS 510A User Manual
3–29
Figure 3–16: Define FFT Waveform Menu
6. Press Set FFT Source to
(side) repeatedly until the channel source selected
in step 1 appears in the menu label.
7. Press Set FFT Vert Scale to
(side) repeatedly to choose from the following
vertical scale types:
H dBV RMS — Magnitude is displayed using log scale, expressed in dB
relative to 1 V
RMS
where 0 dB =1 V
RMS
.
H Linear RMS — Magnitude is displayed using voltage as the scale.
H Phase (deg) — Phase is displayed using degrees as the scale, where
degrees wrap from –180_ to +180_.
H Phase (rad) — Phase is displayed using radians as the scale, where
radians wrap from –p to +p.
The topic Considerations for Phase Displays, on page 3–37, provides in
depth information on setup for phase displays.
8. Press Set FFT Window to
(side) repeatedly to choose from the following
window types:
H Rectangular — Best type for resolving frequencies that are very close to
the same value but worst for accurately measuring the amplitude of those