[SI-LIST] Re: How many simulated bits are confident using HSPICE generating eyediagram.
- From: Hermann Ruckerbauer <hermann.ruckerbauer@xxxxxxxxxxxxx>
- To: si-list@xxxxxxxxxxxxx, emcesd@xxxxxxx
- Date: Mon, 04 Jul 2011 12:32:04 +0200
Hi Tesla,
Steve already mentioned most of my thoughts:
What I usually do is to simulate a step response and take a look how
long it takes until the signal has setteled. Based on this you can
select which PRBS length you need to take in order to capture the worst
case ISI (there are some papers out describing this approach).
On the X-talk there is the brute force method as Steve describes, but as
this is very time consuming (especially when having more aggressors). I
use a different method that is not that accurate, but captures most of
X-talk effects while minimizing runtime:
Take the PRBS pattern that you run on the Victim and run the same
pattern on all agressors (even X-talk) in the second step (same
simulation) take the PRBS pattern from the Victim and run an inverted
pattern on all Aggressors. This approach might not capture the worst
case X-talk, but limits the simulation time to running the PRBS sequence
two times at a reasonable accuracy.
The better option might be to use a statistical approach for your
simulation (not sure if HSPICE includes such thing in the meantime).
Simulate a stepresponse to characterize the Channel (or use
S-Parameters), and based on frequency domain characteristics a dataeye
(including X-talk) can be calculated. There are many simulators out that
can do such stuff in the meantime ...
Best regards
Hermann
EKH - EyeKnowHow
Hermann Ruckerbauer
www.EyeKnowHow.de
Hermann.Ruckerbauer@xxxxxxxxxxxxx
Veilchenstrasse 1
94554 Moos
Tel.: +49 (0)9938 / 902 083
Mobile: +49 (0)176 / 787 787 77
Fax: +49 (0)3212 / 121 9008
schrieb steve weir:
> The answer depends on what you want to know.
>
> If you want to capture your basic channel characteristics under the
> intended encoding scheme, then figure out your maximum run length and
> pick a PRBS sequence that is long enough to capture that run length and
> simulate the entire sequence.
>
> If you are trying to do something like evaluation of crosstalk on the
> eye, then brute force starts to get expensive in simulation time. The
> brute force method is to use a different PRBS on each aggressor than the
> victim, and then run the product of the two sequence lengths.
>
> Steve.
> On 7/4/2011 12:42 AM, Tesla wrote:
>> Hi All,
>> I will simulate a Multi-Gigabit Serial Link(10Gbps) using HSPICE. I
>> want to generating eye diagram as the final result, But i don't know how
>> many bits to run ? Can someone give me some hints?
>> Best Regards.
>> ------------------------------------------------------------------
>> To unsubscribe from si-list:
>> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>>
>> or to administer your membership from a web page, go to:
>> //www.freelists.org/webpage/si-list
>>
>> For help:
>> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>>
>>
>> List technical documents are available at:
>> http://www.si-list.net
>>
>> List archives are viewable at:
>> //www.freelists.org/archives/si-list
>>
>> Old (prior to June 6, 2001) list archives are viewable at:
>> http://www.qsl.net/wb6tpu
>>
>>
>>
>
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
