Dear all I have some s-parameter simulation problem. I have s-parameter file extracting from board file and simulate it by Hspice. According to the input signal, I extracted the s-parameter with sufficient bandwidth and points (input signal: 125MHz, S-parameter bandwidth : 5GHz 1000pts/linear). When simulating, the output waveform will vary with input rise/fall time enormously and also simulation time. The most accurate waveform will occur when the input rise/fall time set to 0.8ns and simulation time set to some specific value. Even though the rise/fall time set to larger or smaller than 0.8ns the output waveform will get inaccuracy. The s-parameter bandwidth is larger than knee frequency of input signal and I also filtered out high harmonic component of input signal (input signal is an idea 50/50 duty pulse) by 5 order low-pass filter ( cut-off frequency set to 10 times the input knee frequency). Why the s-parameter can just simulate at specific input condition accurately? How could I use s-parameter more accurately? Thanks. Terence ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu