HI Stanley, I'm not sure if I have understood your question. Did you find some difficulties in observing the differential signal or in creating a differential stimulus? In the first case one way is to use the command print print PAR('(v(outputpos)-v(outputneg))') In the second case I suppose you want to use a VCVS to feed negate the negative driver. I noticed that it's impossible (maybe I'm wrong?) to connect a VCVS to an input (nd_in) IBIS model in HSPICE. Sometime I connect two separate voltage sources that act in opposition of phase. This is good if you want to simulate some kind of asymmetry between positive and negative output. Onother way is to connect two port to the same voltage source, being sure that the positive output IBIS model has the attribute Polarity Non-Inverting and the other one has Polariy Inverting. If the model doesn't own the attribute (sometimes it happens) You can add it to the IBIS model. Hope this help you. By Giovanni -----Messaggio originale----- Da: Stanley.Chiu@xxxxxxxxxx [mailto:Stanley.Chiu@xxxxxxxxxx] Inviato: Wednesday, July 16, 2003 8:16 AM A: si-list@xxxxxxxxxxxxx Oggetto: [SI-LIST] ibis in hspice Hi ,Experts one question regarding to ibis model usage in hspice, we know that we can use two separate buffers to form a , for example, Tx+ and Tx- pair and observe their respective waveform , but how to observe their diffrential waveform?? do I need to use VCVS syntax to achieve this? if so, I have no idea how to and why using VCVS syntax, can someone pls enlighten me a bit about this ? or an example will be appreciated! Stanley Stanley Chiu Mitac Corp. S.I. Engineer RD7/HSSD Div. TEL:03-3289000 ext323 ------------------------------------------------------------------ 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 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 ------------------------------------------------------------------ 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 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