Phase noise simulation of an XOR gate based frequency doubler

Hi ,

I am trying to calculate phase noise at the output of an XOR gate. The XOR gate input are two quadrature clocks @ 500MHz and output is a 1GHz clock. I have some arbitrary noise spectral density ( phase noise ) assigned to the 500MHz clocks upto 500MHHz frequency offset from the carrier(500MHz in this case). I want to see the phase noise curve for the output of the XOR gate at 1GHz.

Please let me know if the following methodology is correct :

1) Shooting pss with beat frequency 500MHz, 10 harmonics , errpreset=moderate , tstab=100ns (circuit stabilizes pretty quickly)

2) pnoise setup : beat frequency = 500MHz (evaluated from the pss analysis); sweeptype = relative ; relative harmonic=2  ( 1GHz is second harmonic of 500MHz and is the output frequency of XOR gate); Input source= Voltage ( Arbitrary phase noise profile has been assigned to the source). Reference sideband = - 1 ( as 500MHz=1GHz-1*500MHz.).

Is the pnoise setup described above is correct ?

Is the same pnoise setup valid for any subharmonic injection locked system ?

Thanks & Regards

Vishal