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Cannot get the Lorentzian plot in Pnoise simulation

ycyang

Hi,

I am trying to run the PSS+Pnoise to get the linewidth of the VCO.
I have set the Pnoise option "augmented=yes" for PSS+Pnoise oscillator simulations.
Nevertheless, I cannot get the Lorentzian plot, the phase noise still goes up and becomes larger than 0 dBc at low frequencies.
The logfile says:"Compute Floquet mode for autonomous ciruits... ...".
It seems the simulator does not use frequency-aware PPV method.

Is there anything wrong in my setting?
By the way, the MMSIM version I use is 7.2ISR7

Thanks

Parents
  • Andrew Beckett

    Hi ycyang,

    Looking at the log file, I see you're using MMSIM 7.2.0.109 . That is the base version of MMSIM72 and is not ISR7 that you mentioned earlier. That is before the ISR4 version I mentioned earlier. Before we introduced the lorentzian parameter, when augmented was yes (which was not "yes" by default before ISR3, although the augmented algorithm was enabled always for HB), it also plotted with the Lorentzian shape. It should be correct.

    However, I would probably advise moving to a later version than the one you're using, because at the very least this linkage of the Lorentzian shape with the augmented switch is confusing, to say the least (which is why we sorted it out in ISR4).

    I'm a bit confused because initially you said you couldn't get the Lorentzian plot, and now you're saying that you are getting it - and this is nothing to do with the lorentzian parameter you've added, since you're using a version prior to that parameter being supported. I suspect your earlier run was done without augmented being set to yes?

    Regards,

    Andrew.

Reply
  • Andrew Beckett

    Hi ycyang,

    Looking at the log file, I see you're using MMSIM 7.2.0.109 . That is the base version of MMSIM72 and is not ISR7 that you mentioned earlier. That is before the ISR4 version I mentioned earlier. Before we introduced the lorentzian parameter, when augmented was yes (which was not "yes" by default before ISR3, although the augmented algorithm was enabled always for HB), it also plotted with the Lorentzian shape. It should be correct.

    However, I would probably advise moving to a later version than the one you're using, because at the very least this linkage of the Lorentzian shape with the augmented switch is confusing, to say the least (which is why we sorted it out in ISR4).

    I'm a bit confused because initially you said you couldn't get the Lorentzian plot, and now you're saying that you are getting it - and this is nothing to do with the lorentzian parameter you've added, since you're using a version prior to that parameter being supported. I suspect your earlier run was done without augmented being set to yes?

    Regards,

    Andrew.

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