User`s guide

68 Agilent InfiniiVision 2000 X-Series Oscilloscopes User's Guide
4 Math Waveforms
• Source 1 — selects the source for the FFT. (See "To perform a
transform function on an arithmetic operation" on page 64 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 65.
• 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 65.
• More FFT — displays the More FFT Settings Menu.
2 Press the More FFT softkey to display additional FFT settings.
• Window— selects a window to apply to your FFT input signal:
• Hanning — window for making accurate frequency measurements or
for resolving two frequencies that are close together.
• Flat Top — window for making accurate amplitude measurements of
frequency peaks.