This section discusses typical View S-Parameters Tool characteristics and displays. Let us know if you would like the View S-Parameters Tool enhanced with additional capability.

A typical SerDes channel, with about 18 nsec time delay, defined for use with serial data at a bit rate of 25 Gbps has its hardware 4-Port S-parameters measured from 10 MHz to 40 GHz in steps of 3.125 MHz.

For this example S-Parameter file, and with all 4 ports selected for measurement with phase unwrapped, the S-Parameter characteristics can displayed in graphs selected to be opened.

Figure 1: Passivity check

The passivity factor, Max SS*, at any frequency is the maximum value calculated from the expression:

Max SS* = max(  Sum(i=1, 2, …, N){  |Sij|^2  }  )  for each j=1, 2, …, N

When Max SS* is greater than unity, the S-Parameters are non-passive.

Figure 2:  Reflection Sii magnitude

Besides the magnitude response, the phase response can also be viewed.  One can zoom in onto any area in the graph.

Figure 3:  Transmission Sij, i>j, magnitude

Besides the magnitude response, the phase response can also be viewed.  Additionally, the reverse transmission characteristic (Sij, i<j) can be viewed.  One can zoom in onto any area in the graph.