Arpad,
I would document it by passing bird 166, and reference my statement, and
Ambrish's comments as well.
Walter
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On Thu, Jun 8, 2017 at 12:11 PM -0400, "Muranyi, Arpad"
<Arpad_Muranyi@xxxxxxxxxx> wrote:
Walter,
So the question then is how we are going to document this.
In the last ATM meeting Ambrish suggested that we should just copy the
statement on pg. 178:
to the redriver flow section to make sure no one misses it. With this
statement we would not
need to make any changes in the flows, i.e. we can forget about BIRD166. Would
you agree to
this, or do you have something else in mind?
Thanks,
Arpad
========================================================================
From: Walter Katz [mailto:wkatz@xxxxxxxxxx]
Sent: Thursday, June 8, 2017 5:42 AM
To: Muranyi, Arpad <Arpad_Muranyi@xxxxxxxxxx>; ibis-macro@xxxxxxxxxxxxx
Subject: RE: [ibis-macro] Re: Comments on BIRD166.3 and last week's ATM
discussion
Arpad, Ken,
To be clear:
If any of the models in the channel have Init_Returns_Impulse=False then one
cannot do a statistical analysis including the equalization of
all of the AMI Models unless the EDA tool creates a “proxy AMI_Init” from the
input and output of its AMI_GetWave function. SiSoft gave a paper at the 2017
DesignCon on how to do this – divide the FFT of the AMI_GetWave output by the
FFT of the AMI_GetWave
input.If any of the models in the channel have GetWave_Exists=False, then one
cannot do a time domain analysis using the equalization any of the
AMI_GetWave functions unless the EDA tool creates a “proxy AMI_GetWave” from
the input and output of its AMI_AMI_Inir function. IBIS 6.0 says this can be
done by deconvolving the AMI_Init output by the AMI_Init input.
The implementation of either proxy AMI_Init or proxy AMI_GetWave functions can
be
problematic.
I think the debate in IBIS-ATM is what should the standard say (if anything)
about the cases that require a proxy AMI_Init or AMI_GetWave. Fangyi correctly
describes the “problematic”
issues when Tx2 and Rx2 in the Redriver flow have AMI_GetWave=False – either
the proxy AMI_GetWave are incorrect because of the non-linear nature of the Rx2
equalization or the Rx2 AMI_Init does not get the Impulse Response of the full
upstream equalization.
The only thing we can do at this point is that we document this issue. Even if
and when we implement in the standard the additional Impulse Response outputs
of AMI_Init as
proposed by Keysight, we still need to document this issue for legal legacy
models.
Walter
