[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 17:00:06 -0700

Walter,
 
Too bad that I didn't save that half done flow I put on
the screen a week ago Tuesday.  (Does Live Meeting save it
under  the share area by any chance, so we could retrieve it
and look at it once again)?
 
In that version I started with the "final flow" from last
November, and deleted the Init_Returns_Filter Boolean.
When I got done with that, I had pages 2 and 3 (I believe)
on which the flow wouldn't have worked without deconvolution
to get the results as indicated on the final flow.  When I
brought this problem up in last week's teleconference,
Ambrish and/or Fangy (I am not sure) made the suggestion to
"go back to the original flow" as described on pg. 1-2 of:
 
http://www.vhdl.org/pub/ibis/macromodel_wip/archive/20091009/arpadmurany
i/AMI%20flows:2009%20Sept%2029%20proposal%20-%20fixed/AMI_Flows_2fixed.p
df
 
and then everything will be "nice and clean" without needing
deconvolution.  This is exactly what I did for the flow I
showed in today's meeting.  Pg. 2 of the above presentation
was perceived as the ONLY change we needed to make to correct
the error in the 5.0 specification, and the rest of the changes
were perceived as "new features" that belonged to another BIRD.
 
Regardless of how hard I tried to argue that what was perceived
as new features in the final flow from last fall were just
corrections to a flawed flow, the group voted 4 against 3 last
week saying that those features were new features.
 
So the question I want to get answer for from everyone on this
list is this:
 
What additional flaws exist in the spec flow (if any), other than
the reversal of the order between steps 4 and 5 as shown on pg 1
in the above presentation?
 
It seems that as long as we do not agree on this question we will
not have an agreement on how to fix it either...
 
Thanks,
 
Arpad
==================================================================

________________________________

From: Walter Katz [mailto:wkatz@xxxxxxxxxx] 
Sent: Tuesday, April 20, 2010 5:52 PM
To: Muranyi, Arpad; Ambrish Varma; IBIS-ATM
Subject: RE: [ibis-macro] Re: AMI_Flows_6.pdf for today's ATM
teleconference


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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