When i simulate a osicllator which is about 8meghz ,i find that the transient step should be 0.05ns. If the step is longer such as 0.5ns the output will be a line. that's why? By the way , if i keep the scale of the inveter and when the W exceed a certain length, the ouput will be a line too. Can somebody know that tell me why? Thank you. best regards yqzheng gz.china ---------------------------------------------- [ƯÁÁMM]ÐÎÏó´óʹÌùͼ´óÈü¿ªÊ¼Í¶Æ±À² http://free.21cn.com/huodong/plmm/vote.html Òƶ¯¿¨À²ok£¬¶À¼ÒÊÔ³ª http://mms.21cn.com/ring/ring.jsp ±»³ÇÊÐÀÓÓ¡µÄÅ®ÈË µ¥ÉíÇé¸è³ª¶à¾Ã£¿ http://news.21cn.com/social/ 21CNÉÌÎñÓÊÏäÎåÒ»8ÕÛÓŻݣ¬·áºñ½±Æ·µÈÄãÄà http://mail.21cn.com/huodong/0405/business/detail.html ÆóÒµÓÊÏäÏÄÈÕ´óÓŻݣ¬ÊÖ»ú¡¢MP3¼´Ê±ËÍ http://mail.21cn.com/huodong/0405/corpmail/ ------------------------------------------------------------------ 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