N2809A Datasheet, PDF (5/11 Pages) Keysight Technologies – Bandwidths up to 33 GHz

05 | Keysight | PrecisionProbe for Bandwidths up to 33 GHz - Data Sheet
PrecisionProbe Correction
Two methods exist for correcting probe responses, Vout/Vin and Vout/Vsource
Vout/Vin Correction
Vout/Vsource Correction
Vout/Vin characterizes the output of the probe as a func-
tion of the input at the probe tips. Defining the response
this way allows you to evaluate the probe’s accuracy in
reproducing the actual signal present in your system with
the probe attached. This correction is known as Vout/Vin,
which is what you’d see with a real band limited probe that
has finite input impedance. PrecisionProbe corrects the
“Vout/Vin” response to be flat with frequency and phase to
your defined bandwidth limit. It does not correct the loading
effects of the probe. It should be noted that Keysight’ s
probe frequency response corrections are typically defined
using Vout/Vin.
The second way to correct probes is an estimate known as
Vout/Vsource, this method corrects the probe as “what
would be there if the probe were not present.” There are
oscilloscope and probe manufacturers that design their
probes and DSP correction software to display what the
waveform “would have been” in the absence of the probe.
One drawback of defining the probe’s response in this
manner is that if the probe’s loading causes your circuit to
lose some timing or amplitude margin, you probably want to
know that when you make a measurement. Vout/Vsource
compensation will hide these effects from you. Precision-
Probe also gives you the freedom to choose this method
of correction, which can be effective if probing at
the transmitter.
Figure 6: A probe that has perfect transfer function shows an exact copy of a signal at the input. A probe that has a perfect system re-
sponse shows the signal at the input of probe boosted by the estimate amount of loading due to the probe.