[time-nuts] Designing and building an OCXO and GPSDO

[John Miles]

> The R+S FMU36 has a phase noise floor of around -143dBc/Hz (offset >
> 10kHz) with a 10MHz input.
> Whereas the R+S FSU67 has a phase noise floor of around -133dBcdBc/Hz
> (offset = 10kHz) with a 640Mhz input.
>
> There is a definite improvement at lower frequencies but not quite as
> much as one might have expected.

The *floor* of a YTO loop is not very dependent on the carrier frequency, as
the loop bandwidth usually ends up less than 100 kHz.  It's more interesting
to look at the inband noise at 1 - 10 kHz offsets.  The FSU67 looks great in
that department:
http://www.testbuyer.com/pdf/specs.cfm?pdf_id=56025C0EC7

Looks like it spanks the Agilent by a good 10 dBc/Hz.  I want one. :)

-- john, KE5FX