I made a user defined source to model SSB phase noise on a LO. The model works fine when the LO spectrum is viewed. THe problem is that the LO phase noise spectrum is not translated to the mixer IF output. This happens for both passive mixer models. If the phase noise source is applied to the RF port of the mixer and the LO is CW, then the IF output is correct (the phase noise appears). I am using version 2004.07 and the "all signals within -200 dBc of strongest" is selected on the mixer LO area of the Spectrasys options tab. Is this a known problem?
1) The amplitude of the phase noise through mixers, multipliers, and dividers cannot be changed without changing the spectrum that it is attached to since they are one in the same.
2) We couldn't create measurements to operate on the phase noise alone since once again is was part of the desired signal spectrum.
3) For the same reasons phase noise on the LO would not give the anticipated results.
Consequently, only CW signals on the LO port of a mixer could be support in the current and prior releases.
The up coming 2005 release addresses these issues.