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

  • From: "Walter Katz" <wkatz@xxxxxxxxxx>
  • To: <Arpad_Muranyi@xxxxxxxxxx>, "Ambrish Varma" <ambrishv@xxxxxxxxxxx>, "IBIS-ATM" <ibis-macro@xxxxxxxxxxxxx>
  • Date: Tue, 20 Apr 2010 18:51:33 -0400

Ambrish, Arpad,

You neglected to include the beginning of section 2.3. You also seam to have
forgotten that I proved that this flow was fundamentally flawed and that it
required that the Tx GetWave be LTI. This is the fundamental reason why
SiSoft uses the flow that we presented two years ago, and again last year.

All models that SiSoft has developed, and are currently being distributed by
IC Vendors, comply with the flow that Arpad presented last November, support
both statistical and time domain flows, and do not use Init_Returns_Filter.
I can assure you that this is required in order to correlate with IC Vendor
simulation and measurement data.

I strongly recommend that we revert to the flow we developed together last
November, and simply modify it to choose all of the decision branches that
applied when Init_Returns_Filter is True.


Walter



|
| 2.3 Reference system analysis flow
|
|  System simulations will commonly involve both TX and RX algorithmic
|  models, each of which may perform filtering in the AMI_Init call, the
|  AMI_Getwave call, or both.  Since both LTI and non-LTI behavior can be
|  modeled with algorithmic models, the manner in which models are
|  evaluated can affect simulation results.  The following steps are
|  defined as the reference simulation flow.  Other methods of calling
|  models and processing results may be employed, but the final simulation
|  waveforms are expected to match the waveforms produced by the reference
|  simulation flow.
|
|  The steps in this flow are chained, with the input to each step being
|  the output of the step that preceded it.
|
|  Step 1. The simulation platform obtains the impulse response for the
|          analog channel.  This represents the combined impulse response
|          of the transmitter's analog output, the channel and the
|          receiver's analog front end.  This impulse response represents
|          the transmitter's output characteristics without filtering, for
|          example, equalization.

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 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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