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Measurements >> Phase Noise and Jitter Measurements >> Modelling jitter in clock distribution networks
https://designers-guide.org/forum/YaBB.pl?num=1171561846

Message started by pkdas on Feb 15^th, 2007, 9:50am

Title: Modelling jitter in clock distribution networks
Post by pkdas on Feb 15^th, 2007, 9:50am

Hi,
I want to model two jitter in leaf nodes ina clock distribution network in matlab.I am presently doing that by generating gaussian random variable arrays for the periods and then adding them for finding each rising edge of the leaf nodes.But I feel that is a wrong process as by that the variance of the farther edges is increasing with the no. of samples.So what can I do?Is there any alternative model which would be more realistic?
Thanks in advance.
Pratap

Title: Re: Modelling jitter in clock distribution network
Post by Visjnoe on Feb 15^th, 2007, 11:30am

Dear Pratap,

you now generate a random, Gaussian variable for each period, so you're actually modeling period jitter.
I think that your approach is right.

Indeed, the uncertainty of the edges increase in a sqrt(N) sense, but that is also the case in reality (accumulative jitter of an oscillator generating your clock).

Kind Regards

Peter

Title: Re: Modelling jitter in clock distribution network
Post by pkdas on Feb 15^th, 2007, 11:22pm

Thanks Visjnoe,
But the problem I want to convey is that I want the relative jitter ogf two leaf nodes of the same clock tree.If they have independent jitter and their variance is unbounded then if I am interested in finding their relative skew by finding out their average I can't.So I feel in this case as they are coming from the same clock generator their relative jitter should be bounded.But I don't know how to model that.Can u/anybody give any suggstion on how to go around this problem?
Thanks again,
pratap