Hi Todd, Thanks for your detailed response. Reading through IBIS 5.0 spec, Section 10, Item 2.3 helped a lot and cleared my doubts. Thanks Anand -----Original Message----- From: Todd Westerhoff [mailto:twesterh@sisoft.com] Sent: Tuesday, July 14, 2009 9:57 PM To: Anand Ramalingam Cc: ibis-users@eda.org Subject: Re: [IBIS-Users] IBIS - AMI - questions Anand, You're not missing anything - your comment "I don't understand how Transmitter Equalizer (G_teg) can act on Receiver Initialization (h_rei)" is the precise reason why the 4th through 6th equations on slide 11 are shown in red. SiSoft was calling attention to the same issue, also mentioned on slides 12 and 13. By way of history - the presentation you're referencing: http://www.eda.org/pub/ibis/macromodel_wip/archive/20080603/sisoft/IBIS- AMI%20Terminology%20Proposal/IBIS_ATM_Terminology_Update_060308.pdf was created as background material for BIRD 107. There were two issues on the table at the time: 1. The relationship between the Init() and Getwave() calls in an Algorithmic model that implemented equalization in both calls 2. The nature of the time-domain waveform passed to TX_Getwave Both of these issues arose from tests that showed the SiSoft and Cadence AMI test programs were making different assumptions about what data would be passed to AMI Algorithmic models and how the model outputs would be utilized. The first discussion point resulted in the creation of the Reserved Parameter "Use_Init_Output" and the definition of the "Reference System Analysis Flow" (IBIS 5.0 spec, Section 10, Item 2.3) The second discussion point was whether the input to TX_Getwave should be what's currently defined (an "analog waveform"), or whether the input to TX_Getwave should be b(t) * p(t) (a "digital waveform"). SiSoft had strong reservations about the analog waveform input to TX_Getwave, as the presentation indicates. SiSoft seemed to be the only company with those concerns, and there wasn't a pressing need for TX models with Getwave() support at the time. Rather than belabor the point, we made note that an enhancement for TX_Getwave would be required in the future (slides 12 and 13) and left the input to TX_Getwave as others had interpreted it. The TX_Getwave issue is one of several enhancements to IBIS-AMI that have been identified for a new BIRD. The IBIS-ATM group was discussing this specific issue earlier today, along with a number of others. The IBIS-ATM group meets Tuesdays at Noon Pacific, 3PM Eastern. We'd welcome your participation in those meetings, and on the IBIS-ATM reflector (ibis-macro@freelists.org). Incidentally, there was never any problem with RX_Getwave. The issue was limited to TX_Getwave, for the reasons you outlined. Please let me know if this answered your original question! Todd. Todd Westerhoff VP, Software Products SiSoft 6 Clock Tower Place, Suite 250 Maynard, MA 01754 (978) 461-0449 x24 twesterh@sisoft.com www.sisoft.com Anand Ramalingam wrote: > Dear IBIS Experts, > > I have a problem understanding the equations laid out in the following > presentation > > http://www.eda.org/pub/ibis/macromodel_wip/archive/20080603/sisoft/IBIS- > AMI%20Terminology%20Proposal/IBIS_ATM_Terminology_Update_060308.pdf > > > First, I will present my understanding and derive the equation at the > output of the receiver. > > IBIS-ATM Equations: > > > (*) First at the Transmitter: > > |------| |--------| |-----------| > prbs(p) --->--| b |--->--| h_tei |--->--| G_teg(.) |--->-- x(t) > |------| |--------| |-----------| > > Assuming h_tei is an impulse response (LTI) and G_teg(.) is non-LTI > > The output of the transmitter > x(t) = G_teg ( p(t) * b(t) * h_tei(t) ) --------- (1) > > (*) Then through a LTI channel: > > |--------| > x(t) --->--| h_cr |--->-- output of the channel = y(t) > |--------| > > Assuming h_cr is LTI > y(t) = x(t) * h_cr(t) --------- (2) > > > (*) Then finally at the Receiver: > |--------| |-----------| > y(t) --->--| h_rei |--->--| G_reg(.) |--->-- z(t) > |--------| |-----------| > > Assuming h_rei is LTI and G_reg(.) is non-LTI > > The output of the receiver > > z(t) = G_reg ( y(t) * h_rei(t) ) --------- (3) > > > If AMI_Init is not implemented then the corresponding h_?ei is set to > delta function (x * h_?ei = x) > > Putting together Eqns. (1) -- (3) one gets: > > > > > > > z(t) = G_reg ( > G_teg ( > p(t) * b(t) * h_tei(t) > ) > * h_cr(t) > * h_rei(t) > ) -------------------------- (4) > > > But in the presentation ( > http://www.eda.org/pub/ibis/macromodel_wip/archive/20080603/sisoft/IBIS- > AMI%20Terminology%20Proposal/IBIS_ATM_Terminology_Update_060308.pdf > ) in slide 11, > > the following equation is presented. > > > z(t) = G_reg ( > G_teg ( > p(t) * b(t) * h_tei(t) > * h_cr(t) > * h_rei(t) > ) > ) -------------------------- (5) > > > Clearly Eq(4) and Eq(5) are not the same. > I don't understand how Transmitter Equalizer (G_teg) > can act on Receiver Initialization (h_rei). > Can someone clarify what mistake I am making in deriving Eq (4)? > > Thanks > Anand > > > > > -----Original Message----- > From: Anand Ramalingam > Sent: Thursday, July 09, 2009 6:04 PM > To: 'Muranyi, Arpad'; ibis-users@eda.org > Subject: RE: [IBIS-Users] IBIS - AMI - questions > > Hi Arpad, > > In your DAC 2008 presentation you had mentioned that you will make > MATLAB code for IBIS-AMI available on the web. Can you point me to the > web link? > > Thanks > Anand > > > -----Original Message----- > From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On > Behalf Of Muranyi, Arpad > Sent: Friday, June 12, 2009 2:35 PM > To: ibis-users@eda.org > Subject: RE: [IBIS-Users] IBIS - AMI - questions > > Anand, > > 1) As far as I know there are several vendors who support IBIS-AMI, > including my employer, Mentor. I will let the Synopsys people > answer your question about HSPICE specifically. > 2) To my knowledge there is no Cookbook on IBIS-AMI available yet. > However, you can browse through the presentations on the topic > on the IBIS web page and get some ideas from them. > http://www.vhdl.org/pub/ibis/summits/index-bydate.htm > 3) A full fledged .IBS file alone is not going to help you much > because there is really not much in the .IBS file other than a > pointer to the AMI DLL and its parameter file (.ami). What you > need is a good example (i.e. a working DLL) with an appropriate > parameter file (.ami) and a simulator that can run them. > > I hope this helps, > > Arpad > ===================================================================== > > -----Original Message----- > From: owner-ibis-users@server.eda.org > [mailto:owner-ibis-users@server.eda.org] On Behalf Of Anand Ramalingam > Sent: Friday, June 12, 2009 2:24 PM > To: ibis-users@server.eda.org > Subject: [IBIS-Users] IBIS - AMI - questions > > Hi, > > I had a few questions regarding the IBIS AMI which has been included in > the IBIS 5.0. I read through the BIRD document and looked at the > evaluation kit from SiSoft for AMI. > > (1) Are AMI constructs supported by Hspice or any other simulator? > (2) Is there any IBIS cookbook style document which describes how to do > the modeling? > (3) A full-fledged IBIS (*.ibs) file with the proposed AMI constructs > would really help my understanding. > > Thanks > Anand > > > -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. -------------------------------------------------------------------- |For help or to subscribe/unsubscribe, e-mail majordomo@eda-stds.org |with the appropriate command message(s) in the body: | | help | subscribe ibis <optional e-mail address, if different> | subscribe ibis-users <optional e-mail address, if different> | unsubscribe ibis <optional e-mail address, if different> | unsubscribe ibis-users <optional e-mail address, if different> | |or e-mail a request to ibis-request@eda-stds.org. | |IBIS reflector archives exist under: | | http://www.eda-stds.org/pub/ibis/email_archive/ Recent | http://www.eda-stds.org/pub/ibis/users_archive/ Recent | http://www.eda-stds.org/pub/ibis/email/ E-mail since 1993Received on Wed Jul 15 09:53:56 2009
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