Stats

  • Locked Locked
  • Replies 5
  • Subscribers 62
  • Views 15790
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

difference between the two phase noise functions in Direct Plot Form?

Soner

Hi,

I am trying to simulate the phase noise of a 25GHz LC oscillator using pss (flexible balance) and pnoise analysis. In the Direct Plot Form, there are two different Phase Noise options:

1) Analysis: pnoise  Function:Phase Noise

2) Analysis: pnoise jitter Function: Phase Noise

The two above give different results (#1 is approximately ~2.3dBc lower than #2 @ 10MHz offset). What is the difference between these two functions?

I would like to note that #1 provides much more numerically stable results than #2.

 

Parents

  • Hi Andrew,

    I am using reltol 1e-7, vabstol 1e-9 and iabstol 1e-12 and conservative in harmonic balance. I have an LC VCO with amplitude control (where I can change a bias voltage and increase the amplitude of oscillation). At two different bias voltages, (everything else the same) I observe phase noise of -117.7 and -125.7 dBc/Hz at 10MHz respectively. When I sweep tstab, I observe < 5mdBc/Hz numerical noise on -117 but I observe ~ 200mdBc/Hz numerical noise on -125.7 dBc/Hz. Based on your reply, 0.2 dBc noise is too much, isn't it? What other simulation parameters would you recommend me to adjust?

    Thanks for your fast response and regards,

    Soner

Reply

  • Hi Andrew,

    I am using reltol 1e-7, vabstol 1e-9 and iabstol 1e-12 and conservative in harmonic balance. I have an LC VCO with amplitude control (where I can change a bias voltage and increase the amplitude of oscillation). At two different bias voltages, (everything else the same) I observe phase noise of -117.7 and -125.7 dBc/Hz at 10MHz respectively. When I sweep tstab, I observe < 5mdBc/Hz numerical noise on -117 but I observe ~ 200mdBc/Hz numerical noise on -125.7 dBc/Hz. Based on your reply, 0.2 dBc noise is too much, isn't it? What other simulation parameters would you recommend me to adjust?

    Thanks for your fast response and regards,

    Soner

Children
No Data

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.