Walter,
What does your tool do if the model does return these thresholds
but the values are wrong?
Thanks,
Arpad
===================================================
From: Walter Katz [mailto:wkatz@xxxxxxxxxx]
Sent: Monday, November 2, 2020 12:17 PM
To: Muranyi, Arpad <Arpad_Muranyi@xxxxxxxxxx>; IBIS-ATM
<ibis-macro@xxxxxxxxxxxxx>
Subject: RE: [ibis-macro] Re: I will not be able to attend next week's IBI-ATM
meeting ...
Arpad,
I will not attend tomorrow's meeting 11/3.
Our tools do not ignore the PAM4 threshold returned by the model. If a model is
non-com-pliant and does not return the thresholds then we use our own.
Walter
Walter Katz
Work 508.647-7633
Cell 720.417-3762
[Description: Description: Visit MathWorks.com]
From: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>
<ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>> On
Behalf Of Muranyi, Arpad
Sent: Monday, November 2, 2020 12:32 PM
To: 'IBIS-ATM' <ibis-macro@xxxxxxxxxxxxx<mailto:ibis-macro@xxxxxxxxxxxxx>>
Subject: [ibis-macro] Re: I will not be able to attend next week's IBI-ATM
meeting ...
Walter,
Regarding "I will not be able to attend next week's IBI-ATM meeting", are you
talking
about tomorrow (11/3), or 11/10?
Regarding the PAM4 thresholds, are you saying that your tools basically ignore
what
the AMI Rx returns for the PAM4 thresholds and use their own? If that's true,
why
should we require the model to return these values?
Thanks,
Arpad
==================================================================
From: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Walter Katz
Sent: Monday, November 2, 2020 10:37 AM
To: 'IBIS-ATM' <ibis-macro@xxxxxxxxxxxxx<mailto:ibis-macro@xxxxxxxxxxxxx>>
Subject: [ibis-macro] I will not be able to attend next week's IBI-ATM meeting
...
All,
I will not be able to attend next week's IBI-ATM meeting. We do not care about
making the PAM4 thresholds optional, reasons are explained below. There is also
a discussion below about Redriver flow that is based on a new reserved
parameter that specifies that the input to all AMI_Init functions is the IR
matrix of the cumulative upstream channel.
SiSoft/MathWorks does not care if we change returning PAM4 thresholds to be
optional.
* SerDes Toolbox will continue to output valid PAM4 thresholds
* QCD already calculates PAM4 thresholds from the IR output of Rx
AMI_Init or the waveform output of AMI_GetWave if the model does not output them
The Redriver flow solutions is quite simple, and requires some realistic
assumptions and a new reserved parameter Tx_IR_Input_Is_Upstream_Channel
True|False
* Default is False
* If False then no change to current flows, although certain combinations
of Init_Only, GetWave_Only and Dual models are problematic
* If True the input to a Tx is the IR of the Upstream Channel
* For a primary Tx, the Impulse Matrix are Unit Impulse Responses
* For Redriver Tx, the Impulse Matrix is the output of the Rx AMI_Init
* Whether True or False, the input to each Rx is the total upstream channel
* Redriver flows (all assume Tx_IR_Input_Is_Upstream_Channel=True)
* The flow is straightforward if all of the AMI models are Dual models
* The flow is straightforward if all of the AMI models are Init only
models
* The flow is straightforward if all of the AMI models are GetWave only
models
* Assume one redriver, there are 81 combinations of Init_Only,
GetWave_Only and Dual models
* As a practical mater, the only buffer that equalizes itself is the
terminal Rx
* With the exception of the terminal Rx, any Init_Only model can be
made into a Dual model by making its input a unit impulse response, therefore
the output IR of the model will be the equalization of the model. The IR that
can be passed to the next stage is the total upstream IR convolved with the
model equalization convolved with the IR of the downstream channel to the next
model. The "GetWave" output of this model is the total upstra, waveform
convolved with the model equalization convolved with the IR of the downstream
channel to the next model. Note the symmetry on how GetWave and Init work.
* The only real problem is if the downstream Rx is Init_Only and it
optimizes itself based on the total upstream impulse response and any one of
the upstream models is GetWave_Only.
Walter