[ibis-macro] Re: FW: [IBIS-Users] AMI convolution
- From: "Mellitz, Richard" <richard.mellitz@xxxxxxxxx>
- To: "wkatz@xxxxxxxxxx" <wkatz@xxxxxxxxxx>, IBIS-ATM <ibis-macro@xxxxxxxxxxxxx>
- Date: Thu, 19 Nov 2009 09:51:18 -0700
Hi Walter,
I was thinking about this some. Does this flow preclude a modal impulse
response flow? The single channel voltage transfer impulse response really
requires 4 entities based on s11, s21, s12, and s22. A multi-conductor response
requires more.
... Rich
From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx]
On Behalf Of Walter Katz
Sent: Wednesday, November 18, 2009 12:14 PM
To: IBIS-ATM
Subject: [ibis-macro] FW: [IBIS-Users] AMI convolution
All,
In case you are not in ibis-users@xxxxxxx .
Walter
Walter Katz
303.449-2308
Mobile 720.333-1107
wkatz@xxxxxxxxxx
www.sisoft.com
-----Original Message-----
From: Walter Katz [mailto:wkatz@xxxxxxxxxx]
Sent: Wednesday, November 18, 2009 12:00 PM
To: Eric Monteiro; ibis-users@xxxxxxx
Subject: RE: [IBIS-Users] AMI convolution
Eric,
Asking who is responsible for convolution is like asking who is responsible for
Fourier Transform. Convolution is a mathematical technique that EDA tools can
use on the input and output of AMI models, and convolution is a mathematical
technique that can be used inside of the AMI model to apply a filter. The
following describe who may or must use convolution for the "Preferred Flows".
Preferred flows assume both the Tx and Rx model have Init_Returns_Filter=True
and Use_Init_Ouput=True.
Assuming a preferred statistical flow, the EDA tool supplies an impulse
response of the channel to the TX Init function. Inside the Tx Init function
(i.e. inside the AMI model), the model would compute an impulse response of its
filter and return it to the EDA tool. The EDA tool would convolve this impulse
response with the impulse response of the channel and present these results to
the Rx Init. The Rx Init would determine the impulse response of its filter,
and return it to the EDA tool. The EDA tool would then convolve it with the
impulse response that was presented to Rx Init to determine the impulse
response of the channel equalized by both the Tx an Rx filters. The EDA tool
will process this and may use the convolution mathematic technique (e.g. on
probability distribution functions) to generate bathtub curves and bit error
rates. So in the preferred statistical flow the EDA tool does convolution and
the AMI model might not. I could image that the AMI models may use the
convolution technique to generate the impulse response of the filter.
Assuming the preferred time domain flow, the EDA tool must first run the
statistical flow (it need not analyze the results of Rx Init). The EDA tool
supplies a stimulus waveform to Tx GetWave. The EDA tool may or may not use the
convolution generate this waveform. The Tx GetWave will generate an equalized
stimulus waveform with techniques that may or may not use convolution. The EDA
tool must us uses convolution to apply the impulse response of the channel with
this Tx equalized stimulus waveform. The waveform is then presented to Rx
GetWave. Rx GetWave may or may not used convolution to apply its equalization
filter to it's input. The output of Rx GetWave is a waveform, and clock ticks.
The EDA tool may or may not use convolution to analyze this waveform to
generate bathtub curves and bit error rate. So in the preferred time domain
flow, the EDA tool must use convolution, and the AMI model might not.
Walter
Walter Katz
303.449-2308
Mobile 720.333-1107
wkatz@xxxxxxxxxx
www.sisoft.com
-----Original Message-----
From: owner-ibis-users@xxxxxxx [mailto:owner-ibis-users@xxxxxxx]On Behalf Of
Eric Monteiro
Sent: Wednesday, November 18, 2009 10:55 AM
To: ibis-users@xxxxxxx
Subject: [IBIS-Users] AMI convolution
Hi everyone,
I was hoping someone could clarify who is responsible for convolution in
IBIS-AMI (EDA tool, or the modeler).
Clearly the convolution involving an FIR filter is upon the modeler, the
convolution I speak of is the one that is done with the channel response.
My understanding has been as follows: (please correct me if I'm wrong)
(a) -- (Tx IC) -- (passive channel) --(b)--(Rx IC)
You force an impulse at (a), measure the response at (b). (b) is the analog
channel response hAC(t). GetWave then needs a wave, which should be an ideal
bit train, convolved with the bit period (creates a piece wise linear wave)
which is then convolved with hAC(t) to produce the wave fed into GetWave.
There was discussion as to whether the modeler or the EDA tool should do the
above convolution. Has it been decided who this task falls on?
Best Regards,
Eric Monteiro
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