[ibis-macro] Re: What part of Legacy IBIS is used by IBIS-AMI

  • From: "Muranyi, Arpad" <Arpad_Muranyi@xxxxxxxxxx>
  • To: 'IBIS-ATM' <ibis-macro@xxxxxxxxxxxxx>
  • Date: Wed, 11 Jul 2012 14:37:44 +0000

Greg,

The IBIS specification is intentionally silent about
how to generate the impulse response for the channel,
because there are different ways to do it, and EDA
vendors might want to use their own "smarts" to do it
the "best" way.

You are correct, if someone wants to extract such an
"ideal" IR, you would only make use of the C_comp and
the impedance provided by the I-V curve from the analog
model.

BIRD 120 doesn't give any more detail (or restrictions)
on how to generate the impulse response.  So the EDA tool
is free to do it the way they think it is the best to do
it.

I hope this helps,

Arpad
===========================================================

From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] 
On Behalf Of Gregory R Edlund
Sent: Wednesday, July 11, 2012 9:15 AM
To: 'IBIS-ATM'; ibis-macro-bounce@xxxxxxxxxxxxx
Subject: [ibis-macro] Re: What part of Legacy IBIS is used by IBIS-AMI


What if an EDA programmer wanted to discard the VT and ramp data and compute an 
"ideal mathematical" impulse response assuming a delta function?  Is that 
allowed by BIRD 120?  I took a quick look and didn't see anything specific 
about how to calculate the impulse response.  In the "ideal mathematical" case, 
I would think all you need is C_Comp and some resistance extracted from the IV 
tables.

Greg Edlund
Senior Engineer
Signal Integrity and System Timing
IBM Systems & Technology Group
3605 Hwy. 52 N  Bldg 050-3
Rochester, MN 55901



[Inactive hide details for "Walter Katz" ---07/11/2012 03:53:30 AM---I 
agree.]"Walter Katz" ---07/11/2012 03:53:30 AM---I agree.

From: "Walter Katz" <wkatz@xxxxxxxxxx<mailto:wkatz@xxxxxxxxxx>>
To: <Arpad_Muranyi@xxxxxxxxxx<mailto:Arpad_Muranyi@xxxxxxxxxx>>, "'IBIS-ATM'" 
<ibis-macro@xxxxxxxxxxxxx<mailto:ibis-macro@xxxxxxxxxxxxx>>
Date: 07/11/2012 03:53 AM
Subject: [ibis-macro] Re: What part of Legacy IBIS is used by IBIS-AMI
Sent by: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>

________________________________



I agree.

Walter

From: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx> 
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Muranyi, Arpad
Sent: Tuesday, July 10, 2012 11:44 PM
To: IBIS-ATM
Subject: [ibis-macro] Re: What part of Legacy IBIS is used by IBIS-AMI

That is correct.

Arpad
================

From: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx> 
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx]<mailto:%5Bmailto:ibis-macro-bounce@xxxxxxxxxxxxx%5D>
 On Behalf Of Mirmak, Michael
Sent: Tuesday, July 10, 2012 6:07 PM
To: Walter Katz
Cc: IBIS-ATM
Subject: [ibis-macro] Re: What part of Legacy IBIS is used by IBIS-AMI

Walter,

Thank you!  So, someone using IBIS-AMI models with valid traditional data in a 
workflow should expect changes in the IBIS TX C_comp or V-t (or [Ramp]) data to 
have an impact on the results provided by the receiver in an IBIS-AMI-based 
flow, assuming nothing else changes?

-          MM

From: Walter Katz 
[mailto:wkatz@xxxxxxxxxx]<mailto:%5Bmailto:wkatz@xxxxxxxxxx%5D>
Sent: Tuesday, July 10, 2012 12:20 PM
To: Mirmak, Michael
Cc: IBIS-ATM
Subject: What part of Legacy IBIS is used by IBIS-AMI

MM,

The Legacy part of an IBIS model is used to generate the Impulse Response of 
the channel.

One method of generating the impulse response is to do a step response, and 
take the derivative of the waveform at the Rx input.

A simulator uses a combination of the Tx [Voltage Range], C_Comp, IV, VT and 
Ramp data, and the Rx C_Comp and IV data. Of course, [External Model] can also 
be used by a simulator.

The following required Tx IBIS fields are not used in the AMI flow:
Vmeas
The following required Rx IBIS fields are not used in the AMI flow:
Vinl
Vinh

Walter


Walter Katz
wkatz@xxxxxxxxxx<mailto:wkatz@xxxxxxxxxx>
Phone 303.449-2308
Mobile 303.335-6156

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