[time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812A GPSDO system
kb8tq at n1k.org
Mon Nov 17 12:31:40 EST 2014
Here’s the phase noise on the 15 MHz. There are a few spurs, and an very real hump out at the likely frequency of the Lucent switcher. The 15 MHz is pretty clean compared to most /all of the other units I’ve seen on the surplus market.
I would not multiply this up to 40 GHz with a broadband multiplier. I would be quite happy to run it into a PLL with a rational bandwidth. You will beat the noise on the output with a fairly simple VHF VCXO past 100 Hz. No reason to have a bandwidth outside the 20 to 80 Hz range.
15 MHz to 150 MHz -> 20 log (N) -> 20 db.
-140 dbc / Hz shown below at 100 Hz offset -> -120 dbc/Hz
You can get numbers better than -120 dbc/Hz at 100 Hz offset out of a number of pretty simple VHF VCXO circuits. Bert has one that seems to work fine for him.
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