Michael (& all), I don't believe that the TX should shorten its output by the value of Ignore_Bits at all . nor should the RX. The waveform pipeline is the waveform pipeline. Ignore_Bits is part of the contract between the model and simulator, whereby the model declares "the first xxx bits of my output should be ignored" . which implies that there is output that needs to be ignored to begin with (clumsily worded, I know, but I can't come up with better at the moment). Does that make sense? Todd. Description: cid:EAFF2D52-4B63-4A05-9D24-B96BE375B7E0@eau.wi.charter.com Todd Westerhoff VP, Software Products Signal Integrity Software Inc. . <http://www.sisoft.com/> www.sisoft.com 6 Clock Tower Place . Suite 250 . Maynard, MA 01754 (978) 461-0449 x24 . <mailto:twesterh@xxxxxxxxxx> twesterh@xxxxxxxxxx "I want to live like that " -Sidewalk Prophets From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Mirmak, Michael Sent: Wednesday, June 27, 2012 4:31 PM To: IBIS-ATM (ibis-macro@xxxxxxxxxxxxx) Subject: [ibis-macro] ignore_bits and TX vs. RX A deceptively simple question. Ignore_bits as a parameter can apply to the TX or the RX. The language of the specification states that it determines the number of bits to be ignored by the simulation tool. In the case where I have a link where only an isolated TX or an isolated RX, this is easy to understand. But what happens when I combine a TX with an RX on the same link where both use ignore_bits? I would assume that the TX (using GetWave) would provide the tool with a waveform that the tool would then shorten by the stated number of bits (say, 21. But would the RX GetWave then use the shortened waveform in its own analysis, before the tool reports back an even shorter waveform? Specifically, if ignore_bits is 21 in the TX, and ignore_bits is 35 in the RX, does that mean that the final waveform reported out by the tool would be shorter than the original pattern by 56 bits? - MM