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Design >> Analog Design >> Jitter spec for OC192
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Message started by casual on Apr 2^nd, 2009, 2:25am

Title: Jitter spec for OC192
Post by casual on Apr 2^nd, 2009, 2:25am

I am working on the CDR part of OC192 and I am new to it.
There are 3 types of OC192 jitter specification. They re jitter generation, jitter tolerance and jitter transfer. I am not very sure on the jitter spec. This is how I interpret:

Jitter generation: Clean signal is connected into CDR and measure the max pp clock and data jitter, am I correct? What is the max value for this? BER of 10^-12 must be achieved.

The most important spec is the jitter tolerance. The jitter tolerance mask must be complied. BER of 10^-12 must be achieved as well.

As for the jitter transfer, it is somewaht related to jitter tolerance. As long as jitter tolerance mask is complied. Then the jitter transfer will be ok with the condition of max 0.1db amplitude (jitter peaking requirement). Am I correct? How about the required bandwidth? Is the fc 120kHz only?

Hope someone can rectify my misinterpretation.
could you point me some good document about the oc192 jitter spec.

Thanks in advance.

Title: Re: Jitter spec for OC192
Post by Visjnoe on Apr 2^nd, 2009, 2:58am

Dear casual,

the only way to go to translate these high-level specs into architectural/circuit level requirements is to have some form of system model where you can assess the impact of these parameters. If you're lucky, you can find some papers with closed formulae.

Regards

Peter

Title: Re: Jitter spec for OC192
Post by casual on Apr 3^rd, 2009, 1:53am

According to jitter transfer oc192, the cut-off frequency is 120kHz only. However the fc in most of the published journals is around mega hertz range, like 10-20Mhz, which is far exceed the requirement. Is it ok to do so? As I know those journals only focus on jitter tolerance than jitter transfer.

I really confuse :o

Title: Re: Jitter spec for OC192
Post by casual on May 14^th, 2009, 5:11am

Anyone know the reason?