Keysight Technologies N7020A, User Manual

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68 N7020A and N7024A Power Rail Probes User’s Guide
7
Performance Plots
N7024A Performance Plots
N7024A Probe System Responses
Most high performance active probes for use with Infiniium real-time oscilloscopes
utilize DSP correction filters to enhance the measurements accuracy. Probes like
the N7024A store their unique s parameters in on-board memory for the scope to
readout when needed. Probe heads are simple passive devices and, with careful
manufacture, their s-parameters don't vary significantly so they are stored as
nominal s-parameters in the oscilloscope. When a probe is connected to an
oscilloscope channel and the proper probe head is selected, the oscilloscope
calculates a DSP correction filter that includes the probe head, probe amplifier,
and oscilloscope channel. This provides the maximum measurement accuracy for
the complete probe and scope channel system. Since there are different probe
amplifiers and probe head combinations, it is not reasonable to show the
responses of all these combinations and the responses would all be very much the
same because they are all corrected to same target system response. The target
system response is a flat magnitude, flat phase response high order low-pass filter
that maximizes measurement accuracy.
Figure 20 shows an example of a typical corrected system frequency response of
the N7024A probe when used with the N7022A main cable. This is the V
out
/V
in
response which is indicative of the response seen when probing a very low
impedance voltage rail.