[ibis-macro] Re: [IBIS] BIRD107: Update to Algorithmic Modeling API (AMI) Support in IBIS

  • From: "Todd Westerhoff" <twesterh@xxxxxxxxxx>
  • To: <ibis@xxxxxxx>, "'IBIS-ATM'" <ibis-macro@xxxxxxxxxxxxx>
  • Date: Thu, 3 Apr 2008 23:08:25 -0400

Arpad,

I made that change when preparing the BIRD.  The presentation we were reviewing 
on Tuesday was
focusing solely on a TX model how the Init/Getwave calls would be used to 
predict the waveform at
the RX pad.

What I realized while preparing the BIRD was that the language we were using 
could be construed as
requiring a second copy of the channel impulse response to be convolved into 
the waveform presented
to the RX AMI_Getwave call, even when Use_Init_Output is False.

Consider the case where the TX and RX model both implement filtering in 
AMI_Init and AMI_Getwave.
In the case where Use_Init_Output for the RX model is set to False, then the 
output of the TX
AMI_Getwave call should be fed directly into the RX AMI_Getwave call.

The existing language

| If the Reserved Parameter, Use_Init_Output, is set to "False", EDA tools will
| use the original (unfiltered) impulse response of the channel.

Didn't support that clearly.  My concern was that the impulse response of the 
channel would end up
in the output twice in some EDA implementations.  The proposed language was 
ambiguous in the case
where both models have both calls, and Use_Init_Output is True.

This was a realization I had at 5:00 this afternoon, with different key people 
out of the office.
Thus I had a decision to make - change the language and go ahead (I know this 
stuff works, we've
already tested and correlated it) - or wait.  I chose the former.

Sorry if this came as a surprise - there's no hidden agenda here.  There was 
simply a case we forgot
to consider, and I made a change to address it.

We can discuss this further at tomorrow's and next Tuesday's meeting.

Todd.

Todd Westerhoff
VP, Software Products
SiSoft
6 Clock Tower Place, Suite 250
Maynard, MA 01754
(978) 461-0449 x24
twesterh@xxxxxxxxxx
www.sisoft.com

-----Original Message-----
From: owner-ibis@xxxxxxx [mailto:owner-ibis@xxxxxxx] On Behalf Of Muranyi, Arpad
Sent: Thursday, April 03, 2008 8:26 PM
To: ibis@xxxxxxx; IBIS-ATM
Subject: RE: [IBIS] BIRD107: Update to Algorithmic Modeling API (AMI) Support 
in IBIS

Excuse me, but how did the language on pg. 18 of this presentation:
http://www.vhdl.org/pub/ibis/macromodel_wip/archive/20080401/toddwesterh
off/IBIS-AMI%20Correlation%20and%20BIRD%20Update/IBIS_ATM_BIRD_Update_04
0108.pdf
change from:

| If the Reserved Parameter, Use_Init_Output, is set to "False", EDA
tools will
| use the original (unfiltered) impulse response of the channel.
| The algorithmic model is expected to modify the waveform in place.

into what is in the text of the BIRD107:

| If Use_Init_Output is set to "False", the EDA platform will present
the 
| input waveform directly to the AMI_Getwave call (i.e. without
convolving 
| the waveform with the impulse response returned by AMI_Init).

The two paragraphs have a significant difference and I didn't see
any discussion on that change...  Could someone please explain that
to me?  What happened with the "impulse response of the channel"?

Thanks,

Arpad
=====================================================================
 

-----Original Message-----
From: owner-ibis@xxxxxxxxxxxxxx [mailto:owner-ibis@xxxxxxxxxxxxxx] On
Behalf Of Mirmak, Michael
Sent: Thursday, April 03, 2008 5:09 PM
To: ibis@xxxxxxxxxxxxxx
Subject: [IBIS] BIRD107: Update to Algorithmic Modeling API (AMI)
Support in IBIS


The enclosed BIRD, "Update to Algorithmic Modeling API (AMI) Support in
IBIS," is submitted on behalf of Todd Westerhoff, SiSoft and Zhen Mu,
Cadence Design Systems.  It will be introduced and discussed at an
upcoming IBIS Open Forum teleconference.

All resolved and pending BIRDs can be found at http:// <<bird107.txt>>
www.eda.org/ibis/birds/.

- Michael Mirmak
  Intel Corp.
  Chair, IBIS Open Forum

 

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