Using De-embedding Tools for Virtual Probing
应用文章
Using De-embedding Tools to Gain Virtual Access to
Difficult Measurement Points
With today’s high levels of component and platform integration, measuring signals that can’t be physically accessed is becoming the norm. Determining S-parameters with Keysight Technologies, Inc. EM field solvers can provide virtual measurement capability when direct measurement is not possible So far, this series of papers have shown how S-parameter models can be used to de-embed the response of the interconnect between the oscilloscope probe and the point of interest:
“virtual probing.” Let’s now consider the question of how to obtain that S-parameter model in the first place. The obvious method – connect a VNA to each end of the interconnect and measure the S-parameters – works in some cases. Subtracting the effects of a long cable is an example. But what if one end is inaccessible? After all, the main premise of virtual probing is exactly that: it’s hard to place a probe on the point of interest. For these cases, the solution is modeling based on an electromagnetic (EM) field solver, EM-based modeling for short.