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 Phase Noise at PIO vs. Parameter 

Last post Fri, Dec 21 2012 8:26 AM by Andrew Beckett. 1 replies.
Started by baenischfau 20 Dec 2012 11:16 PM. Topic has 1 replies and 546 views
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  • Thu, Dec 20 2012 11:16 PM

    Phase Noise at PIO vs. Parameter Reply

    Hi there,

    I'm simulating a VCO at the moment and I want to create a plot which shows

    PhaseNoise@100kHz vs. tuning voltage of the VCO. However I'm having trouble

    in getting the plot.The simulation is a PSS simulation with PNOISE that uses

    a symbolic parameter that tracks with vdd to ensure that vtune does not exceed

    the supply voltage. This range is then divided into 30 intervals to simulate PhaseNoise

    at different VCO frequencies.

    I get the various PhaseNoise plots but if I apply a value measurment @ 100kHz

    to the waveforms I only get a single waveform measured.

    The generated measurement within the calculator looks like this:

     

    value(value(_drplPmNoise(?modifier "dBc") "vtune" 0.0) 100k)

     

    which indicates that only the waveform with a tuning voltage of 0.0 is considered.

    I have extended the list to include more voltages and it works but this approach

    has some negative side effects if I change to supply voltage and therefore also the

    voltage tuning range of the VCO. As the intervall is tracking with vdd I get different

    voltages each time I change the settings for the supply :(

    Is there an easy way to tell ADE that I just want a value measurement for all available

    graphs without having to specify tons of voltage values ?

     

    Best Regards

     

    Andi

    • Post Points: 20
  • Fri, Dec 21 2012 8:26 AM

    Re: Phase Noise at PIO vs. Parameter Reply

    Andi,

    That's odd. I don't know how you did the sweep (or which version you were using), but normally the inner sweep should be the frequency sweep of the pnoise analysis, and the outer sweep would have been whatever you set up as the sweep on the PSS analysis form (assuming that's what you did - you really didn't describe the sweep setup) or using Tools->Parametric analysis in ADE.

    So it ought to work using

    value(_drplPmNoise(?modifier "dBc") 100k)

    To remove any ambiguity about which variable you wish to slice though in the value function, you should be able to do:

    value(_drplPmNoise(?modifier "dBc") 'freq 100k)

    (From the expression I'm assuming you've set up to use "modulated" or "jitter" mode (in FM mode) on the pnoise form).

    Regards,

    Andrew.

    • Post Points: 5
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Started by baenischfau at 20 Dec 2012 11:16 PM. Topic has 1 replies.