Hello Andrew, thanks your reply. Now i know that i cant compare that two different waveform directly. We know that in specctraquest the Bufferdelay must to be avoided to count doublely . The Bufferdelay is used to correlate the interconnect delay at different loads conditions, In hspice simulation ,can i say that this kind of Bufferdelay is meaningless ? -- Best regards, qzheng mailto:qzheng@xxxxxxxxxxxxxxxx ------------------------------------------------------------------ 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