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

  • From: James Zhou <james.zhou@xxxxxxxxxx>
  • To: "Arpad_Muranyi@xxxxxxxxxx" <Arpad_Muranyi@xxxxxxxxxx>, 'IBIS-ATM' <ibis-macro@xxxxxxxxxxxxx>
  • Date: Wed, 11 Jul 2012 12:29:25 -0700

Arpad,

According to BIRD120 step 6b and 6c, when Tx AMI_GetWave does  not exist, the 
digital stimulus is convolved with the impulse response.

Thanks for your confirmation on differential signaling.

James


From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] 
On Behalf Of Muranyi, Arpad
Sent: Wednesday, July 11, 2012 12:22 PM
To: 'IBIS-ATM'
Subject: [ibis-macro] Re: What part of Legacy IBIS is used by IBIS-AMI

James,

That digital stimulus has nothing to do with the impulse
response of the channel.  That is the input to the Tx
AMI_GetWave function.

But you are correct, the impulse response is differential.
For example, if the impulse response is generated by taking
the derivative of a step waveform observed at the Rx, the
waveform that you would use is the difference waveform
between the two traces of a differential pair.

I hope this helps,

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

From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] 
On Behalf Of James Zhou
Sent: Wednesday, July 11, 2012 2:08 PM
To: wkatz@xxxxxxxxxx; gedlund@xxxxxxxxxx; 'IBIS-ATM'; 
ibis-macro-bounce@xxxxxxxxxxxxx
Subject: [ibis-macro] Re: What part of Legacy IBIS is used by IBIS-AMI

Walter,

According to BIRD120, the digital stimulus has amplitude range of -0.5 to +0.5 
and all transitions occur at zero crossing. Since this range mostly applies to 
differential signals, does it mean that the impulse response should also be 
differential impulse response? If the V-T curves are provided separately for 
pin+ and pin-, their impulse responses have to be obtained separately and then 
combined into a single differential impulse response.

James


From: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx> 
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx]<mailto:[mailto:ibis-macro-bounce@xxxxxxxxxxxxx]>
 On Behalf Of Walter Katz
Sent: Wednesday, July 11, 2012 7:40 AM
To: gedlund@xxxxxxxxxx<mailto:gedlund@xxxxxxxxxx>; 'IBIS-ATM'; 
ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>
Subject: [ibis-macro] Re: What part of Legacy IBIS is used by IBIS-AMI

Greg,

Yes, almost. You still need a voltage swing either extracted from the VT 
curves, Ramp data or [Voltage Range]. You would be assuming a zero rise time 
for the driver. This is equivalent to the simple Tx Analog Buffer Circuit 
described in BIRD 122.

Walter

From: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx> 
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx]<mailto:[mailto:ibis-macro-bounce@xxxxxxxxxxxxx]>
 On Behalf Of Gregory R Edlund
Sent: Wednesday, July 11, 2012 10:15 AM
To: 'IBIS-ATM'; 
ibis-macro-bounce@xxxxxxxxxxxxx<mailto: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



[cid:image001.gif@01CD5F60.CED6B890]"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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