User`s guide

168 5000 Series Oscilloscope User’s Guide
4 Making Measurements
• 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.
• Preset — sets the frequency Span and Center to values that
will cause the entire available spectrum to be displayed.
The maximum available frequency is half the effective FFT
sample rate, which is a function of the time per division
setting. The current FFT sample rate is displayed above
the softkeys.
2 Press the More FFT softkey to display additional FFT
settings.
• Scale — lets you set your own vertical scale factors for FFT
expressed in dB/div (decibels/division). Press the Scale
softkey, then turn the Entry knob to rescale your math
function.
• 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. Press the Offset softkey, then turn
the Entry knob to change the offset of your math function
FFT Scale FFT Offset
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