66 Agilent InfiniiVision 2000 X-Series Oscilloscopes User's Guide
4 Math Waveforms
 
A scale unit of U (undefined) will be displayed for math functions when 
two source channels are used and they are set to dissimilar units and the 
combination of units cannot be resolved.
Math Operators
Math operators perform arithmetic operations (add, subtract, or multiply) 
on analog input channels.
• "Add or Subtract" on page 66
• "Multiply or Divide" on page 67
Add or Subtract
When you select add or subtract, the Source 1 and Source 2 values are 
added or subtracted point by point, and the result is displayed.
You can use subtract to make a differential measurement or to compare 
two waveforms.
If your waveforms' DC offsets are larger than the dynamic range of the 
oscilloscope's input channels you will need to use a differential probe 
instead.
* When the FFT source is channel 1, 2, 3 or 4, FFT units will be displayed in dBV when channel 
units is set to Volts and channel impedance is set to 1 M
Ω. FFT units will be displayed in dBm 
when channel units is set to Volts and channel impedance is set to 50
Ω. FFT units will be 
displayed as dB for all other FFT sources or when a source channel's units has been set to Amps.
Math function Units