iep wrote on Jan 19th, 2010, 8:05am:1. The nature of the pnoise tool within Spectre RF is such that it cannot accurately predict phase noise perfromance below the corner frequency of the phase noise ?
You may think so.
iep wrote on Jan 19th, 2010, 8:05am:This is simply because the Lorentzian spectrum models are inaccurate in the presence of flicker noise?
No.
It is simply due to limitation of small signal noise analysis in frequency domain.
See
http://www.designers-guide.org/Forum/YaBB.pl?num=1050465395/26#26iep wrote on Jan 19th, 2010, 8:05am:2. Using augmented mode in HB mode will cause the spectrum of the noise to flattened out below the flicker noise limit.
In shooting mode it is not flattened out and will still exceed 0dBc as it approaches 0Hz offset from the carrier.
In which case, what is the real benefit of augmented mode?
Does it improve accuracy above the flciker noise offest from the carrier?
Again see
http://www.designers-guide.org/Forum/YaBB.pl?num=1050465395/28#28iep wrote on Jan 19th, 2010, 8:05am:3. There seems to be a broad consensus that the augmented mode does not really improve accuracy below the flicker noise limit of the phase noise?
Ideally augmented mode should be helpful for improving accuracy of phase noise for small offset frequency region except for non-physical value region.
Even in Agilent ADSsim, phase noise analysis using HB had to be improved.
Again see
http://www.designers-guide.org/Forum/YaBB.pl?num=1050465395/20#20This improvement for Agilent ADSsim has been completed in 2001 or 2002.
But I think there are still many many bugs in augmented pnoise of Cadence Spectre.
iep wrote on Jan 19th, 2010, 8:05am:4. The results I am seeing at frequencies greater than the flicker noise corner are probaly accurate?
It is not accurate result generally.
Again see
http://www.designers-guide.org/Forum/YaBB.pl?num=1050465395/26#26iep wrote on Jan 19th, 2010, 8:05am:5. Other posts have reffered to the Linewidth, does the linewidth simply refer to the frequency offset from the carrier below which flicker noise dominates?
I don't know how Cadence Spectre defines "linewidth".
I guess it forces an adaptation of phase noise as "the Lorentzian spectrum form" regardless of flicker noise existence.
Then it defines "linewidth" so that it has an integrated area of one.
But I'm not sure.
See
http://www.cadence.com/community/forums/T/12466.aspxStill there is no answer.
iep wrote on Jan 19th, 2010, 8:05am:Unfortunately, I am particularly interestd in the phase noise performance close in to the carrier.
It apperas these results will be very difficult to establish.
Use full-spectrum oscillator device noise analysis(oscnoise) of BDA's Analog FastSPICE RF.
This analysis is fairly different from conventional phase noise analysis based on small signal noise analysis in frequency domain which is major in many vendor's simulators.
Again see
http://www.designers-guide.org/Forum/YaBB.pl?num=1258339986/42#42