Reply To: How to set differential prope parameters in ANSYS for extracting S parameters

[Mrinmoy Bharadwaj]

Hello lijunfang,
Firstly, you do not extract S-parameters from a TDR probe. TDR probe is for looking at the trace impedance in the time domain. 
In case you meant extracting the TDR for your PCB, the pulse repetition frequency is generally kept 2 times of the pulse width. This is a general practice only.