[ibis-macro] Re: AMI_Flows_6.pdf for today's ATM teleconference

  • From: "Muranyi, Arpad" <Arpad_Muranyi@xxxxxxxxxx>
  • To: "IBIS-ATM" <ibis-macro@xxxxxxxxxxxxx>
  • Date: Tue, 20 Apr 2010 17:38:35 -0700

Ambrish,
 
How can you make such a bold statement about the future:
"However for non-linear models, there will be no equalization (that
approximates the equalization in the GetWave) in the Init function..."?
It makes me feel that I should come to you for advise on
how to make my investments... :-)
 
I think this is exactly what some of us disagrees with you.
Walter may even come back saying that they have already made
models like that, but I will let him speak for himself...
 
From this I am starting to get the impression that we are
really not talking about a flow issue here, but the question
of what the intent was between the Init and GetWave functions
regarding supporting LTI and non-LTI devices in the same model.
 
I thought this question was settled before in my message to
Ken (included below).  Why are we still dwelling on it?
 
Arpad
================================================================
 
 
-----Original Message-----
From: Muranyi, Arpad 
Sent: Wednesday, March 31, 2010 12:35 AM
To: 'IBIS-ATM'
Subject: Comment on Sigrity's presentation
 
Ken,
 
I would like to make a comment on slide 3 of the presentation
you gave us in the ATM teleconference a week ago and the
discussion that followed.
 
http://www.vhdl.org/pub/ibis/macromodel_wip/archive/20100323/kenwillis/S
igrity%20AMI%20BIRD%20Feedback/Sigrity_AMI_BIRD_fback.pdf
 
If I understood the discussion correctly, you and Kumar are
concerned that one model could produce different results
when only its Init functions are used vs. when its GetWave
functions are also used.  The discussion between you and Todd
ended in a disagreement.
 
However, it just occurred to me that the AMI portion of the
IBIS 5.0 specification already talks about the possibility
of having two types of analysis paths, one that only uses
the Init functions (for LTI systems), and another that also
involves the GetWave function when non-LTI effects are present.
This is found in Section 10, 2.1 and 2.2 in the specification.
 
Doesn't this close the discussion we had in the meeting when
you were presenting in a sense that you are challenging an
intent that is already clearly spelled out in the specification?
 
Thanks,
 
Arpad
=================================================================
 


________________________________

From: ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Ambrish Varma
Sent: Tuesday, April 20, 2010 7:08 PM
To: IBIS-ATM
Subject: [ibis-macro] Re: AMI_Flows_6.pdf for today's ATM teleconference



Hi Arpad,

Sorry - I did mean Nonlinear, and/or Time Variant. 

Well, there is a link. For a linear model, there will be no getwave, so
slide 5 will correctly represent the scenario. However for non-linear
models, there will be no equalization (that approximates the
equalization in the GetWave) in the Init function, as such Tx (and RX)
Use_Init_Output will always be true. This would also mean that these
models (with Getwave) would not be suitable for Stateye type
simulations.

 

Only models that would like to perform both Stateye type simulation as
well as (meaningful) Time Domain simulation via the same model will have
issues as a straight path from Tx_Init to Rx_Init is needed for Stateye
type sim. 

 

In my opinion, if we follow the simple rule set out by the spec, a lot
of the confusion will automatically be resolved.

 

Please let me know if I was clear enough. :-)

Thanks,

Ambrish.

 

________________________________

From: ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Muranyi, Arpad
Sent: Tuesday, April 20, 2010 6:38 PM
To: IBIS-ATM
Subject: [ibis-macro] Re: AMI_Flows_6.pdf for today's ATM teleconference

 

Ambrish,

 

I think you meant "Time-variant" in a few places where you wrote

"Time-invariant"... but aside from that I am not sure what this

has to do with Walter's comment about what goes into Rx_Init.

Can you explain how these two topics are related?

 

Thanks,

 

Arpad

==================================================================

 

________________________________

From: ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Ambrish Varma
Sent: Tuesday, April 20, 2010 5:32 PM
To: IBIS-ATM
Subject: [ibis-macro] Re: AMI_Flows_6.pdf for today's ATM teleconference

Hi Arpad, 

The spec is very clear in delineating between Linear, Time-invariant
model and Nonlinear, and /or Time-invariant models. (section 2, chapter
10). It was expected that a non linear/time-invariant model would not
try and model an approximation of the same algorithm in the Init
function. Also, a linear model would not have a getwave function.

 

Thanks,

Ambrish. 

 

________________________________

From: ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Muranyi, Arpad
Sent: Tuesday, April 20, 2010 6:08 PM
To: IBIS-ATM
Subject: [ibis-macro] Re: AMI_Flows_6.pdf for today's ATM teleconference

 

Walter,

 

Thanks for your feedback.  I think you just made us discover another

discrepancy in the spec.  Contrast what you quoted with this from

the IBIS specification:

 

 

 

 

What do you suggest we should do about this?

 

Arpad

========================================================================

 

________________________________

From: Walter Katz [mailto:wkatz@xxxxxxxxxx] 
Sent: Tuesday, April 20, 2010 4:27 PM
To: Muranyi, Arpad; IBIS-ATM
Subject: RE: [ibis-macro] Re: AMI_Flows_6.pdf for today's ATM
teleconference

Arpad,

 

In the IBIS 5.0 specification:

 

|               Use_Init_Output:

|

|               Use_Init_Output is of usage Info and type Boolean.  When

|               Use_Init_Output is set to "True", the EDA tool is

|               instructed to use the output impulse response from the

|               AMI_Init function when creating the input waveform

|               presented to the AMI_Getwave function.

|

|               If the Reserved Parameter, Use_Init_Output, is set to

|               "False", EDA tools will use the original (unfiltered)

|               impulse response of the channel when creating the input

|               waveform presented to the AMI_Getwave function.

|

|               The algorithmic model is expected to modify the waveform
in

|               place.

|  

|               Use_Init_Output is optional. The default value for this

|               parameter is "True".

|

|               If Use_Init_Output is False, GetWave_Exists must be
True.

 

In what was agreed to in November, the input the Rx_Init was always
hAC(t) X hTEI(t).

In what you presented this week, the input to Rx_Init is either hAC(t)
or hAC(t) X hTEI(t), depending on the value of Tx Use_init_Output. I
believe based on the IBIS 5.0 specification above that the November flow
is correct and the Spec. correction flow that you presented this week is
incorrect.

 

Walter

 

Walter Katz

303.449-2308

Mobile 720.333-1107

wkatz@xxxxxxxxxx

www.sisoft.com

 

-----Original Message-----
From: ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx]On Behalf Of Muranyi, Arpad
Sent: Tuesday, April 20, 2010 12:48 AM
To: IBIS-ATM
Subject: [ibis-macro] Re: AMI_Flows_6.pdf for today's ATM teleconference

 

Here is the AMI_Flows_6.pdf file once again.  I made

the changes which were suggested to me in the last ATM

meeting.  This flow includes only the correction we

wanted to make on the existing spec flow.

 

I am not sure what the decision was about the last two

slides which deal with the Rx pad waveform.  Did we

say we would delete these slides altogether and not

address this capability in this BIRD?  As far as I can

tell, we can't achieve this flow without deconvolution...

 

Please familiarize yourselves with these slides, because

I would like to achieve closure on this flow in the ATM

teleconference tomorrow.  Comments are welcome before or

at the meeting.

 

Thanks,

 

Arpad

=========================================================

 

________________________________

From: Muranyi, Arpad 
Sent: Tuesday, April 13, 2010 1:39 PM
To: 'IBIS-ATM'
Subject: AMI_Flows_6.pdf for today's ATM teleconference

For those who are unable to join the meeting via

LiveMeeting, here is a new flow diagram to aid the

discussion on the subject.

 

Arpad

==================================================

JPEG image

JPEG image

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