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 PSS+(sampled)PAC and PSS+(sampled)PXF 

Last post Fri, Aug 16 2013 4:34 AM by Frank Wiedmann. 1 replies.
Started by sacrb 14 Aug 2013 10:37 AM. Topic has 1 replies and 2729 views
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  • Wed, Aug 14 2013 10:37 AM

    • sacrb
    • Not Ranked
    • Joined on Wed, Aug 14 2013
    • Posts 1
    • Points 20
    PSS+(sampled)PAC and PSS+(sampled)PXF Reply


    I am trying to find the effect of supply noise on the jitter of a delay line (a set of buffers in series). When I went through various documents and I found the following options

    1. PSS + PAC with the sampled option.

    2. PSS + PXF with sampled option

    In the both the cases sampled option is selected since only the jitter at zero crossing is important. http://www.designers-guide.org/Forum/YaBB.pl?num=1224609785

    Let me start with explaining one setup. When I simulate PSS + sampled PAC, I set PAC magnitude = 1 in my power supply voltage source. Set the the maximumsideband = 0, and sweep the input source from 10khz to 10Ghz. The input clock to the delay line is 1GHz.

    I am a little confused with the output spectrum that I see with the above simulation. Since it is sampled PAC, I was expecting the spectrum to repeat every 1GHz (fundamental tone), like in a PSS + sampled PNOISE analalysis. However, in the PSS + sampled PAC I see that the spectrum does not repeat. Can someone explain, what is wrong with my understanding?

    Also, if wanted period jitter (instead of absolute jitter) in a sampled pnoise  simulation, I would multiply the output spectrum with (1-z-1) and divide by slope of the output waveform at the transition point and integrate from 0 - FCLK/2. How do I find the period jitter in a sampled PAC analysis?

    All my questions basically come from the confusion that the output spectrum is not repetitive, like in a sampled system.

    Thanks for help.

    • Post Points: 20
  • Fri, Aug 16 2013 4:34 AM

    • Frank Wiedmann
    • Top 75 Contributor
    • Joined on Wed, Jul 16 2008
    • Muenchen, Bavaria
    • Posts 96
    • Points 1,575
    Re: PSS+(sampled)PAC and PSS+(sampled)PXF Reply
    • Post Points: 5
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Started by sacrb at 14 Aug 2013 10:37 AM. Topic has 1 replies.