[ibis-macro] Re: Question, re: drastic differences between Statistical and Bit-by-bit simulation results.
- From: Gregory R Edlund <gedlund@xxxxxxxxxx>
- To: Arpad_Muranyi@xxxxxxxxxx
- Date: Mon, 9 Apr 2012 09:06:08 -0500
Arpad,
I agree. The Ignore_Bits setting should be a function of the CDR/training
algorithm, which the user should not have to worry about.
Greg Edlund
Senior Engineer
Signal Integrity and System Timing
IBM Systems & Technology Group
3605 Hwy. 52 N Bldg 050-3
Rochester, MN 55901
From: "Muranyi, Arpad" <Arpad_Muranyi@xxxxxxxxxx>
To: "'ibis-macro@xxxxxxxxxxxxx'" <ibis-macro@xxxxxxxxxxxxx>
Date: 04/09/2012 09:04 AM
Subject: [ibis-macro] Re: Question, re: drastic differences between
Statistical and Bit-by-bit simulation results.
Sent by: ibis-macro-bounce@xxxxxxxxxxxxx
Greg,
You are correct, Ignore_Bits is optional. I was kind of
speed reading and didn’t catch the sentence on pg. 145,
I only saw the sentence in the middle of pg. 144...
But this doesn’t change my comment on what Casey said,
because if Ignore_Bits is not in the .ami file, the model
maker must have been happy with its default value of zero.
Also, since the model’s user is not supposed to make changes
to the content of the .ami file, I don’t see why the User’s
Guide of the model should encourage the user to do so by
putting in recommended values for Ignore_Bits.
Thanks,
Arpad
============================================================
From: Gregory R Edlund [mailto:gedlund@xxxxxxxxxx]
Sent: Monday, April 09, 2012 8:10 AM
To: Muranyi, Arpad
Cc: 'ibis-macro@xxxxxxxxxxxxx'; ibis-macro-bounce@xxxxxxxxxxxxx
Subject: Re: [ibis-macro] Re: Question, re: drastic differences between
Statistical and Bit-by-bit simulation results.
Arpad,
I thought Ignore_Bits was optional.
| The following reserved parameters are optional. If the
| following parameters are not present, the values are
| assumed as “0”.
|
| Max_Init_Aggressors:
|
| Max_Init_Aggressors is of usage Info and type Integer. It
| tells the EDA platform how many aggressor Impulse Responses
| the AMI_Init function is capable of processing.
|
| Ignore_Bits:
|
| Ignore_Bits is of usage Info and type Integer. It tells
the
| EDA platform how long the time variant model takes to
complete
| initialization. This parameter is meant for AMI_GetWave
| functions that model how equalization adapts to the input
| stream. The value in this field tells the EDA platform how
| many bits of the AMI_Getwave output should be ignored.
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 "Muranyi, Arpad" ---04/06/2012 05:21:45 PM---I
agree with most everything Casey says, except with thi"Muranyi, Arpad"
---04/06/2012 05:21:45 PM---I agree with most everything Casey says, except
with this: “the model user's guide should have some
From: "Muranyi, Arpad" <Arpad_Muranyi@xxxxxxxxxx>
To: "'ibis-macro@xxxxxxxxxxxxx'" <ibis-macro@xxxxxxxxxxxxx>
Date: 04/06/2012 05:21 PM
Subject: [ibis-macro] Re: Question, re: drastic differences between
Statistical and Bit-by-bit simulation results.
Sent by: ibis-macro-bounce@xxxxxxxxxxxxx
I agree with most everything Casey says, except with this:
“the model user's guide should have some recommendation for 'ignore bits'”
because “Ignore_Bits” is a required AMI reserved parameter
which must be present in every .ami file to tell the EDA tool
how many bits it should ignore. So there is no need for any
recommendations in the User’s Guide.
Thanks,
Arpad
==============================================================
From: ibis-macro-bounce@xxxxxxxxxxxxx [
mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Morrison, Casey
Sent: Friday, April 06, 2012 2:13 PM
To: 'DBanas@xxxxxxxxxx'; 'ibis-macro@xxxxxxxxxxxxx'
Subject: [ibis-macro] Re: Question, re: drastic differences between
Statistical and Bit-by-bit simulation results.
Hi David:
Yes, if there's such a difference then that suggests an issue with the
model or possibly some simulator settings. If the model has a GetWave
function, then it would suggest that GetWave is putting out an all-zero
waveform. I know some models do this until the various adaption algorithms
in the RX reach convergence, at which point they start outputting sensible
data. If this were the case, the model user's guide should have some
recommendation for 'ignore bits', which will basically instruct the
simulator to ignore that waveform data. If the model does not have a
GetWave, then that would suggest an issue with the simulator potentially.
Regards,
Casey
From: David Banas [mailto:DBanas@xxxxxxxxxx]
Sent: Friday, April 06, 2012 01:39 PM
To: 'IBIS-ATM' <ibis-macro@xxxxxxxxxxxxx>
Subject: [ibis-macro] Question, re: drastic differences between Statistical
and Bit-by-bit simulation results.
Hi experts,
If I’ve got a case where a `statistical’ mode simulation produces a
reasonable looking eye, but a `bit-by-bit’ mode simulation of the same
circuit produces a flat line, is that indicative of a particular problem
with the models?
Thanks,
David Banas
Sr. Member Technical Staff
Altera
+1-408-544-7667 - desk
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