HP 54522A - Page 173

Math/FFT Menu
Defining a Function
Diff (differentiate) The voltage of the operand is differentiated in a
oint-by-point manner. Ifa data point is not encountered in the operand,
differentiation uses the next valid data point. Only the available data is
differentiated
Default scaling is determined by the original operand. The differentiation
‘unction, by nature, amplifies noise effects. Therefore, use differentiation on
signals with high signal-to-noise ratios.
FFT (fast Fourier transform) When FFT is selected, a fast Fourier
ransform of the specified channel or memory is displayed. Selecting this
mode adds FFT specific controls to the math menu. When the FFT
function is selected, the readout for the horizontal axis changes from
time to Hertz and the vertical readout changes from volts to dBm.
Chan/Mem Softkey
The chan/mem softkey selects the second operand for use by the selected
operator. You can choose any displayed channel or waveform memory. This
softkey is not available for the magnify, inv, int, diff, or FFT operators.
Sensitivity Softkey
The sensitivity softkey scales the function on the screen. Sensitivity
does not affect the hardware settings in the scope. Sensitivity is adjusted
with the knob or keypad.
Offset Softkey
The offset softkey moves the function vertically on the screen. Offset is
adjusted with the knob or keypad. Also, offset is the value at the center of
the graticule area.
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