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Eye diagram function

starsky

 Hello everyone,

 I have a VCO schematic in which the phase noise is measured using pnoise analysis, the time period is  start: 1; stop: 100M with PSS beat frequency as 5G.

How to use the eye diagram function for this phase noise? I mean, I know the syntax will be 

EyeDiag(Signal, TDelay , TPer , N)  but when I give expression as eyeDiagram(phaseNoise(1 "pss_fd" ?result "pnoise"), 5M, 100M, 3)

 I am able to plot but not able to see the eye diagram as such.

 Pls help.

Parents

  • This doesn't make any sense, for several reasons:

    1. pnoise produces frequency domain results - you see the output noise power spectral density versus frequency.
    2. An eye diagram is a time domain metric - you need time domain waveforms coming into the function - so phaseNoise is completely inappropriate.
    3. Even assuming that you'd run (say) transient noise instead to get a noisy time domain waveform, using the eyeDiagram function doesn't make sense, because it relies on having a fixed clock frequency, which is unlikely to be the case with a VCO.
    4. More likely to be useful with a time domain VCO waveform is to run time domain noise, and then use the freq function to get the instantaneous frequency, and then plot a histogram of that (exactly how depends on whether you're using IC5141 or IC61).
    5. But to be honest, pnoise will be more efficient. Perhaps you can use the "jitter" mode if you want to get some idea of jitter metrics - not really sure what  your goal is.

    Regards,

    Andrew.

Reply

  • This doesn't make any sense, for several reasons:

    1. pnoise produces frequency domain results - you see the output noise power spectral density versus frequency.
    2. An eye diagram is a time domain metric - you need time domain waveforms coming into the function - so phaseNoise is completely inappropriate.
    3. Even assuming that you'd run (say) transient noise instead to get a noisy time domain waveform, using the eyeDiagram function doesn't make sense, because it relies on having a fixed clock frequency, which is unlikely to be the case with a VCO.
    4. More likely to be useful with a time domain VCO waveform is to run time domain noise, and then use the freq function to get the instantaneous frequency, and then plot a histogram of that (exactly how depends on whether you're using IC5141 or IC61).
    5. But to be honest, pnoise will be more efficient. Perhaps you can use the "jitter" mode if you want to get some idea of jitter metrics - not really sure what  your goal is.

    Regards,

    Andrew.

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