[Premium-Rx] Phase noise

[Carcia, Francis A HS]

Hi All,
I wonder if anyone out there knows what a HP 08640-60504  noise phase lock
circuit is? I found it in the 8640 TM
used to phase lock 1 8640 to another to measure phase noise. I want to make
a set up like that to measure RX
synthesizer phase noise. I find the ARRL method dependant on filter
performance.
When I worked at Andersen labs we had a homebrew circuit for measuring phase
noise below -105 dBC.
The spectrum analyzers ran out of steam around -100.   Anybody know of an
app note?  fc