5-18
Making Measurements
Math Scale and Offset
Math Scale and Offset
Any math function may be manually scaled by pressing the Settings soft ke y, an d
then adjusting the Scale or Offset value.
1Press the Settings softkey in the Math menu to set your own scale factors

(units/division) or offset (units) for the selected math function.

Units for each input channel can be set to Volts or Amps using the channel Probe
Units softkey. Scale and offset units are:
A scale unit of U (undefined) will be displayed for math function 1-2 and for
d/dt, and dt when 1-2 or 1+2 is the selected source if channel 1 and channel 2
are set to dissimilar units in the channel Pr obe Units softkey.
2Press the Scale or Offset softkey, then turn the Entry knob to rescale or

change the offset value for your math function.

Math Scale and Offset are Set Automatically
Any time the currently displayed math function definition is changed, the function is
automatically scaled for optimum ver tical scale and offset. If you manually set sc ale
and offset for a function, select a new function, then select the original function, the
original function will be automatically rescaled.
Math function Units
FFT dB* (decibels)
1*2 V2, A2, or W (Volt-Amp)
1-2 V or A
d/dt V/s or A/s (V/second or A/second)
dt Vs or As (V-seconds or A-seconds)
* When the FFT source is channel 1 or channel 2 (or channel 3 or 4 on the 54624A), FFT units
will be displayed in dBV when channel units is set to Volts and chan nel impedance is set to
1M
. FFT units will be displayed in dBm when channel units is set to Volts and chann el
impedance is set to 50 (54640-series only). FFT units will be displa yed as dB for all other FFT
sources or when a source channels units has been set to Amps.