I recently wrote a program to renormalize S-parameter impedance. This lets you measure a filter with a 50 ohm VNA even though the design impedance is higher. In the course of testing the program, I needed to plot S-parameters. I searched extensively for suitable viewers, desktop or online. The ones I located were either incomplete, frustratingly awkward, or had bugs.
I decided to write my own Windows S-parameter plotter. It's near the top of the following page. See the bottom of the page for downloading instructions.
The first image compares group delay for two Murata ceramic filters. The next images show the benefit of phase unwrapping.
Brian
