love_analog wrote on May 1st, 2010, 8:51am:My understand was the dbc/Hz read is really the phase noise.
No.
It is no more than C/N0 ; Carrier Power to Noise Power Density Ratio
love_analog wrote on May 1st, 2010, 8:51am:What is CNR?
C/N ; Carrier Power to Noise Power Ratio.
Noise Marker Mode in conventional Spectrum Analyzer shows C/N0 or C/N.
love_analog wrote on May 1st, 2010, 8:51am:In a practical scenario, how much difference is there between the "real" phase noise and the reading from a spectrum analyzer.
I don't have good examples now.
I can't measure C/N0 at small offset frequency correctly using conventional Spectrum Analyzer.
I have many instruments as well as EDA tools.
When I have spare time, I will create actual measurement examples.
We can't measure Carrier Power correctly because we can't separate carrier and noise clearly in actual measurement.
On the other hand, carrier and noise are evaluated separately in small signal noise analysis subjected to master steady state large signal analysis such as Cadence Spectre PSS/Pnoise.