[ibis-macro] Re: Statistical vs. Time Domain BER Predictions?
- From: "Todd Westerhoff" <twesterh@xxxxxxxxxx>
- To: "'IBIS-ATM'" <ibis-macro@xxxxxxxxxxxxx>
- Date: Thu, 15 Mar 2012 22:38:23 -0400 (EDT)
Arpad,
Statistical simulations using AMI_Init can do a good job of approximating
DFE behavior, even though they're not simulating the bit by bit adaptive
behavior of DFE algorithms.
Mike Steinberger provided a good overview of the approach here:
http://www.eeweb.com/blog/michael_steinberger/what-bumblebees-and-models-o
f-dfe-have-in-common
David,
The answer to your original question is (as it so often is) - "it
depends". Statistical algorithms tend to simulate random, unencoded data
. so, if your time-domain simulation uses 8B10B encoding, that can cause
results to vary significantly (32B33B and 64B66B have much smaller
effects). Another significant factor is the length of the time-domain
simulation, which goes to probability depth. Statistical simulations, by
their very nature, can compute probabilities beyond 1E-30. Time domain
simulations tend to be 1E7 bits or less, so accurately predicting
statistics down to levels we care about (1E12 and less) gets trickier.
Hope that helps,
Todd.
Description: cid:EAFF2D52-4B63-4A05-9D24-B96BE375B7E0@eau.wi.charter.com
Todd Westerhoff
VP, Software Products
Signal Integrity Software Inc. . <http://www.sisoft.com/> www.sisoft.com
6 Clock Tower Place . Suite 250 . Maynard, MA 01754
(978) 461-0449 x24 . <mailto:twesterh@xxxxxxxxxx> twesterh@xxxxxxxxxx
"Three in the morning and I'm still awake,
So I picked up a pen and a page . "
-Sidewalk Prophets
From: ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Muranyi, Arpad
Sent: Thursday, March 15, 2012 7:28 PM
To: 'IBIS-ATM'
Subject: [ibis-macro] Re: Statistical vs. Time Domain BER Predictions?
David,
There is more to it than RMS jitter.
In TD simulations you can include the non-linear DFE
algorithms, for example, which is simply omitted in
Statistical analysis. It's comparing apples and
oranges.
Thanks,
Arpad
==============================================================
From: ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of David Banas
Sent: Thursday, March 15, 2012 6:08 PM
To: 'IBIS-ATM'
Subject: [ibis-macro] Statistical vs. Time Domain BER Predictions?
Hi Experts,
When comparing the BER estimates of the Statistical and Time Domain
operating modes of an EDA tool, would you expect:
1) Statistical to estimate lower or higher BER than time domain?
2) Expect the differences between the 2 modes to go to zero, as the
difference between their estimates of RMS jitter goes to zero? (Said
another way, perhaps: are BER extrapolation errors mainly due to errors in
RMS jitter estimation?)
Thanks!
David Banas
Sr. Member Technical Staff
Altera <http://www.altera.com/>
+1-408-544-7667 - desk
Did you know Altera offers over 150 free online technical training courses
<http://www.altera.com/servlets/searchcourse?coursetype=Online&WT.mc_id=t9
_ot_mi_mi_tx_a_311> ? Take one today!
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