How to do phase noise analysis of QVCO?

[hrkhari]

Hai Guys:

On performing the PNOISE and PSS analysis to determine the phase noise response, in a differential osc configuration there are two output, so we can select one of the nodes as the Oscillator node and the other as the reference node in the PSS oscillator select option, but if one construct a QVCO we have four output, how(which node) do we setup the node for Oscillator node and reference node in the PSS setup form. Thanks in advance

Rgds

 

[BigBoss]

Phase Noise of QVCO

Doesn't matter. PN is independent from quadrature outputs so that tw coupled output can be selected.But they must be coupled so 0,180 degree or 90,270degree..

 

[hrkhari]

Re: Phase Noise of QVCO

Hi:

When I execute the PNOISE and PSS analysis in determining the phase noise of the QVCO designed, the plot is not displayed, whereas an indication says:

Output nodes of pnoise analysis not saved for pss analysis. As a result, the above selected function cannot be executed.

I had done the same procedure in determining the phase noise of a VCO, where there is no problem in executing it. But when I configure the QVCO from the VCO topology the phase noise execution fails. Pls do guide me in obtaining the Phase Noise Plot. Thanks in advance

Rgds