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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