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Jitter measurement with PNoise Edge delay feature

chalresw2014

Hello, I would like to characterize the impact of jitter on the pulse width (td) of the out signal shown below. I would like to understand how phase noise impacts/modulates the pulse width td, and which block is the major noise contributor.

 

I am using Spectre 17.1.0.270, and the new version of Pnoise provides a new feature called "edge delay". So I set it up as it triggers at rising edge of out, and measure at the falling edge of out, such as

pnoise pnoise start=10k stop=1G maxsideband=30 noisetype=sampled \
measurement=[pm0] annotate=status
pm0 jitterevent measure=delay trigger=[out GNDA] triggerthresh=0.5 \
triggernum=1 triggerdir=rise target=[out GNDA] targetthresh=0.5 \
targetnum=1 targetdir=fall

Am I using this feature in the right way? Is it intended to do stuff like this? I am expect to see very little noise contributed from buf0, but in reality , it dominates my noise budget. Any help or explanation will be highly appreciated.

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  • Andrew Beckett

    I think (from a very quick glance) that this looks OK - although I've not played with the edge delay very much yet. Please contact customer support and then we can check through carefully what's going on here to ensure that it's both set up correct and giving reasonable results.

    By the way, what is your clock frequency? I hope it's above 2GHz, because in these sampled modes you should not sweep the noise analysis beyond half the PSS fundamental (otherwise you end up double (or more) counting the noise due to aliasing caused by the ideal sampler which gets inserted when using the sampled noise analyses).

    Regards,

    Andrew

Reply
  • Andrew Beckett

    I think (from a very quick glance) that this looks OK - although I've not played with the edge delay very much yet. Please contact customer support and then we can check through carefully what's going on here to ensure that it's both set up correct and giving reasonable results.

    By the way, what is your clock frequency? I hope it's above 2GHz, because in these sampled modes you should not sweep the noise analysis beyond half the PSS fundamental (otherwise you end up double (or more) counting the noise due to aliasing caused by the ideal sampler which gets inserted when using the sampled noise analyses).

    Regards,

    Andrew

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