Mike, I tend to agree with Ambrish. The EDA tool should take the larger of the two numbers, and exclude the first so many bits from being plotted. I may add, though that the tool could also do other things. For example, if the user requests 1 million bits to be simulated, the tool could simulate 1000035 bits and plot the last 1 million bits for the user (after ignoring the first 35). The spec doesn't say how this should be handled... Thanks, Arpad ============================================================= From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Ambrish Varma Sent: Wednesday, June 27, 2012 3:44 PM To: michael.mirmak@xxxxxxxxx; IBIS-ATM (ibis-macro@xxxxxxxxxxxxx) Subject: [ibis-macro] Re: ignore_bits and TX vs. RX Michael, I would say that the tool would need to ignore only 35 bits in the waveform for deducing the final results. My understanding is that the tool does not really 'shorten' the number of bits by the ignore bits, but actually simply 'ignores' it in the final analysis for results etc, as that is the number of bits required for the models to adapt/optimize or settle down. Thanks, Ambrish. [cid:image002.gif@01CD5480.0555F980] Ambrish Varma | Member of Consulting Staff P: 978.262.6431 www.cadence.com<http://www.cadence.com> ________________________________ From: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx> [mailto:ibis-macro-bounce@xxxxxxxxxxxxx]<mailto:[mailto:ibis-macro-bounce@xxxxxxxxxxxxx]> On Behalf Of Mirmak, Michael Sent: Wednesday, June 27, 2012 4:31 PM To: IBIS-ATM (ibis-macro@xxxxxxxxxxxxx<mailto: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