If you want to observe the deviation from a nominal frequency, for example 10 MHz, instead of the absolute frequency itself, you can do like this:

  • Select Math
  • Select the expression K×X+L
  • Select K = 1 (if not already set)
  • Select L = -10 MHz
  • Now the display will show the deviation from the value you have just entered.

By changing the constant K you can scale the result instead. Set for example K = 60 to convert Frequency in Hz to RPM (revolutions per minute) from rotation transducers.

Use the expression X/M-1 if you want the result to be displayed as a relative deviation. The result will be displayed as

%, ppm, ppb, or as a dimensionless number like +1.2345E-12