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Analog Verification >> Analog Performance Verification >> eye diagram
https://designers-guide.org/forum/YaBB.pl?num=1215765206

Message started by analog_cha on Jul 11^th, 2008, 1:33am

Title: eye diagram
Post by analog_cha on Jul 11^th, 2008, 1:33am

hi All,
Can any body tell how i can write the ocean command to measure the jitter from the eye diagram??
I am aware of measuring it from the plot. But not able to automate it.

Thanks.

Title: Re: eye diagram
Post by sheldon on Jul 11^th, 2008, 7:17pm

Analog_cha,

Have you tried the jitter_meter from the bmslib? It calculates
the jitter directly from the transient output using a reference clock.

Best Regards,

Sheldon

Title: Re: eye diagram
Post by analog_cha on Jul 13^th, 2008, 8:01pm

Dear Sheldon,

I have never heard about bmslib and jitter meter. How is it related to ocean scripting??
Could you share some more info about it.
I am not able to get any thing even after googling.

Thanks.

Title: Re: eye diagram
Post by jbdavid on Jul 15^th, 2008, 11:40am

It doesn't relate to ocean scripting, and It ASSUMES you are running Cadence tools.. -- a full install of which will have a copy of "bmslib".

you place the "jittermeter" model in your schematic.. and run the simulation.. If I recall correctly It captures a number of periods of the input signal and calculates some statistics on the variation in the period. (or did it need a reference clock? )

-- but my concerns have been more with validation of pll operation than measuring the jitter.. usually the designers do that..
--
But I find I can do a heck of a lot of results analysis in a verilogA model, rather than hoping to find a way to post process the results and get the right answer.
jbd

Title: Re: eye diagram
Post by Andrew Beckett on Jan 2^nd, 2009, 4:06pm

You may find the attached SKILL useful. See Sourcelink solution 11395772 too which gives the same code, but with some additional notes.

Andrew.

Title: Re: eye diagram -
Post by apprentice on Apr 4^th, 2011, 8:21pm

how to setup source and analysis for PRBS with spectre?

Assume a transmission line or its S-parameter data to be tested, wanted to simulate eye diagram at the output of it.

thanks

Title: Re: eye diagram
Post by ywguo on Apr 12^th, 2011, 7:24pm

Hi apprentice,

Obviously you have another independent question, you'd better to start a new post in this forum.

Here is a good article that can answer your question.
http://www.designers-guide.org/Modeling/JTOL_rev1.0.pdf

Best Regards,
Yawei

Title: Re: eye diagram
Post by apprentice on Apr 13^th, 2011, 8:17pm

thanks.