[time-nuts] HP10544a Technical Info needed

Dr Bruce Griffiths bruce.griffiths at xtra.co.nz
Fri Feb 2 18:42:18 EST 2007

Howard W. Ashcraft wrote:
> I am constructing a GPS disciplined OCXO using an HP10544a.  If someone
> has a copy of the HP manual/technical data for this oscillator, I would
> appreciate getting a scan.  I have already received, from a request on
> the HP equipment listserv, a copy of an HP10544 schematic.
> Also, while performing tests on the unit, I detected fairly strong noise
> signals leaking onto my test board.  It appears to be coming from pins
> 5/6 of the HP10544a, which are the EFC control pin and its related
> ground.  A spectrum analyzer shows the noise at about -30dbm and peaking
> around 1.8 mhz.  Has anyone seen anything similar with this OCXO?
> Everything else looks normal.
> Regards,

These oscillators use a switchmode oven controller so this is one 
possible source  of noise another possibility is the reference zener.

Have you used the recommended LC filter to isolate the oven controller 
switching transients from the oscillator which is necessary when the 
oscillator and oven controller employ the same 10.6-11.7V power supply?

I have a copy of the 1 October 1972 10544A datasheet if you want a 
scanned copy.


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