[ibis-macro] Re: Truth table taken to the next level

  • From: "Ken Willis" <kwillis@xxxxxxxxxxx>
  • To: <ibis-macro@xxxxxxxxxxxxx>
  • Date: Wed, 28 Apr 2010 11:08:31 -0400

Hi Arpad,

 

My apologies for missing the meeting yesterday, I just returned from
vacation and was digging out.

 

I am concerned that we are going in entirely the wrong direction with this,
in that it is becoming far too EDA-centric and not IP supplier-centric
enough. And I think the latter is what we need to focus on if we are ever to
have a robust pool of Serdes models available for the SI engineering
community to use.

 

I have spoken with a lot of Serdes IP suppliers, and have never heard any
mention of supporting statistical or LTI TD or non-LTI TD or partial
statistical or full non-LTI TD or any other specific kind of analysis. What
I hear is things much more like this:

 

- What IBIS-AMI API do I need to use for my Serdes Tx / Rx? I want to use
the most straightforward approach to model my filter.

- Does the filtering in my Serdes IO do a one-time adaptation to my channel?
If it does I will use the modified impulse response approach, since that is
simplest.

- Does my filtering do real-time dynamic kind of adaptation? If it does, I
will need to use the GetWave approach and process waveforms directly.

 

This is admittedly a little over-simplified, but I think is basically on
target. I think we would do much better to think more along these lines
rather than add all the complexity I see in these tables below. To be
successful, I think we need to keep this as simple as possible, and enable
models to be developed. I would even go as far as to say that the most
practical approach for a given Serdes IO would be to use either the impulse
response or GetWave API, but not both together.

 

I would be interested to hear opinions on these ideas from the people on
this list.

 

Thanks,

 

Ken Willis

Sigrity, Inc.

860-871-7070

kwillis@xxxxxxxxxxx

 

  _____  

From: ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Muranyi, Arpad
Sent: Wednesday, April 28, 2010 1:57 AM
To: ibis-macro@xxxxxxxxxxxxx
Subject: [ibis-macro] Truth table taken to the next level

 

Dear AMI experts, 
  
I cleaned up the spreadsheet with the truth table that we discussed 
in our ATM meeting today.  It looks like this now: 

Picture (Device Independent Bitmap)

I hope I got it right this time. 

The next thing I would like to do is to extend this table 
and spell out how these conditions can be applied to Tx 
and Rx independently.  In other words, I don't believe 
that our intent was to require these Booleans to be the 
same for both Tx and Rx.  But how many combinations are 
valid? 

We have four (4) combinations per buffer, and we have two 
buffers, which could theoretically allow 4^2 = 16 total 
possibilities.  Are they all valid? 

Picture (Device Independent Bitmap)

Thanks, 

Arpad 
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