[time-nuts] Phase-noise through mixer?

[Anders Wallin]

Hi group!

Can someone help me with how phase-noise through a mixer is calculated?

Let's say I connect a 1 GHz signal with -80 dBc/Hz PN (wrt. 1GHz carrier)
at some offset to the RF port.
I then connect a 900 MHz signal with also -80dBc/Hz PN (wrt. 900MHz
carrier) at the same offset.
I'm interested in the 100 MHz IF signal (naively, will it have -77 dBc/Hz
PN wrt 100MHz? carrier?)

(ofcourse there might be a noise-figure through the mixer also)

thanks!
Anders