[ibis-macro] Re: Statistical vs. Time Domain BER Predictions?

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-of-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.

 

Todd Westerhoff

VP, Software Products

 

Signal Integrity Software Inc. • www.sisoft.com

6 Clock Tower Place • Suite 250 • Maynard, MA 01754

(978) 461-0449 x24  •  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

+1-408-544-7667 - desk

 

Did you know Altera offers over 150 free online technical training courses? Take one today!

 

 

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