Keysight Technologies DSO-X 2002A, User Manual

Page: 77 / 352

Math Waveforms
4
Keysight InfiniiVision 2000 X-Series Oscilloscopes User's Guide 77
Use the FFT function to find crosstalk problems, to find distortion problems in
analog waveforms caused by amplifier non-linearity, or for adjusting analog filters.
To display a FFT waveform:
1 Press the [Math] key, press the Function softkey and select f(t) , press the Operator
softkey and select FFT .
• Source 1 — selects the source for the FFT. (See “To perform a transform
function on an arithmetic operation" on page 72 for information about using
g(t) as the source.)
• Span — sets the overall width of the FFT spectrum that you see on the
display (left to right). Divide span by 10 to calculate the number of Hertz per
division. It is possible to set Span above the maximum available frequency, in
which case the displayed spectrum will not take up the whole screen. Press
the Span softkey, then turn the Entry knob to set the desired frequency span
of the display.
• Center — sets the FFT spectrum frequency represented at the center vertical
grid line of the display. It is possible to set the Center to values below half
the span or above the maximum available frequency, in which case the
displayed spectrum will not take up the whole screen. Press the Center
softkey, then turn the Entry knob to set the desired center frequency of the
display.
• Scale — lets you set your own vertical scale factors for FFT expressed in
dB/div (decibels/division). See “To adjust the math waveform scale and
offset" on page 73.
• Offset — lets you set your own offset for the FFT. The offset value is in dB and
is represented by the center horizontal grid line of the display. See “To
adjust the math waveform scale and offset" on page 73.
• More FFT — displays the More FFT Settings Menu.
2 Press the More FFT softkey to display additional FFT settings.