[ibis-macro] Re: AMI-init should pass modified IR to getwave....

  • From: ckumar <ckumar@xxxxxxxxxxx>
  • To: <wkatz@xxxxxxxxxx>
  • Date: Thu, 14 Jun 2012 04:59:58 -0700

my views and original intent  are when a model implements getwave it
should closely approximate the real device . ie. it should input waveform
as a continuous waveform and do what is necessary. Real devices do not do
anything to impulse response because it is an analytic  construct not
available naturally.

If statistical processing is desired a separate init model should do. This
is analogous in circuit modeling where we have a analytic/semi analytic
behavior model and more "real" and complex? silicon level model.

  
On Thu, 14 Jun 2012 07:35:40 -0400 (EDT), "Walter Katz" <wkatz@xxxxxxxxxx>
wrote:
> Kukal,
> 
> 
> 
> So you want to make it easy for the model makers by having Init return
two 
> impulse responses, the current ones that is used for the “Init”
flow,
> and a 
> second one that the EDA tool would presumably use in the following way:
> 
> For Tx, the EDA tool would convolve this second impulse response with
the 
> output of Tx GetWave.
> 
> For Rx, the EDA tool would convolve this second impulse response with
the 
> input to Rx GetWave.
> 
> 
> 
> 1.       Please confirm that this is what you propose to do with the
> second 
> impulse response that you want the Init function to return.
> 
> 2.       And if you do confirm this, cannot the model maker pass this 
> Impulse Response to its GetWave, and have its GetWave do this
convolution.
> 
> 
> 
> Assume you confirm 1., then what is the compelling reason for us to
change 
> the outputs of Init to make it simpler for a model maker to eliminate a 
> trivial convolution that he can do in his GetWave function?
> 
> 
> 
> Walter
> 
> 
> 
> 
> 
> From: Taranjit Kukal [mailto:kukal@xxxxxxxxxxx]
> Sent: Thursday, June 14, 2012 6:53 AM
> To: wkatz@xxxxxxxxxx; 'ibis-macro@xxxxxxxxxxxxx'
> Subject: Re: [ibis-macro] AMI-init should pass modified IR to
getwave....
> 
> 
> 
> Hi Walter,
> I meant model-makers who want to use both init and getwave in
conjunction 
> for transient flow v/s those who want to do everything in getwave.
> 
> Apologize if this statement was confusing..
> 
> Rgds
> 
> 
> 
> From: Walter Katz [mailto:wkatz@xxxxxxxxxx]
> Sent: Thursday, June 14, 2012 02:25 PM
> To: Taranjit Kukal; 'IBIS-ATM' <ibis-macro@xxxxxxxxxxxxx>
> Subject: RE: [ibis-macro] AMI-init should pass modified IR to
getwave....
> 
> 
> Kukal,
> 
> 
> 
> Who are “those” in you statement “those who want to leverage init
as 
> complement to getwave and those who want to keep statistical-flow purely

> independent.”
> 
> 
> 
> Walter
> 
> 
> 
> From: ibis-macro-bounce@xxxxxxxxxxxxx 
> [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Taranjit Kukal
> Sent: Thursday, June 14, 2012 2:04 AM
> To: 'IBIS-ATM'
> Subject: [ibis-macro] AMI-init should pass modified IR to getwave....
> 
> 
> 
> Hi All,
> 
> When I was implementing AMI model, I found a situation where it was 
> important that Rx ami_init needed to pass modified-IR to getwave
function.
> 
> Reason was that Chip-RDL-routing was available as Impulse-Responses.
> 
> Removal for “Use_Init_Output” to make Statistical-flow independent
of 
> Transient-flow,  is going to break the original intent where init and 
> getwave were supposed to work in conjunction with each other handling
> linear 
> and non-linear filtering portions respectively (as shown below)
> 
> 
> 
> cid:image001.png@01CD49C5.F040DCA0
> 
> 
> 
> I would go back to Arpad’s suggestion (year 2010) for having two 
> Impulse-responses coming out of ami_init
> 
> -          One that goes to EDA tool for statistical flow
> 
> -          One that gets passed to getwave to allow splitting of 
> modeling-effort across init and getwave and make things easy for linear 
> filters.
> 
> 
> 
> BIRD120 was brought up that deprecates use of “use_init_output” with
a
> view 
> to keep statistical and time-domain simulations independent. But as I
> think 
> more, we need to allow both capabilities. It absolutely does not make
> sense 
> to implement simple linear filters within getwave when we can convolute
> the 
> filter-IR with channel-IR. We should take all steps to make modeling
easy 
> and ensure enough flexibility.
> 
> 
> 
> This way, we cover both the scenarios – those who want to leverage
init
> as 
> complement to getwave and those who want to keep statistical-flow purely

> independent. Since this does not bring any disadvantage, I strongly feel

> that we all re-consider outputting two modified-IRs out of init function
> – 
> one for statistical-flow and another one to complement getwave
filtering.
> 
> 
> 
> 
> 
> Rgds
> 
> ..kukal
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