[time-nuts] Cs stability

[Björn Gabrielsson]

"Achieved:  Acceleration sensitivities better than 2E-12/g"

http://www.zyfer.com/briefings/telecom/qz%20low-g%20brfg%20olie%204-04.pdf

--

   Björn

On Tue, July 17, 2007 14:40, Rob Kimberley said:
> Another way that has been incorporated successfully to combat g
> sensitivity
> are accelerometers mounted on each of the x, y, Z axes of the crystal.
> Combining this with spring mounts works well. g sensitivities down to e-10
> per g  can be achieved.
>
> Rob K
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of SAIDJACK at aol.com
> Sent: 17 July 2007 06:14
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] Cs stability
>
> ); SAEximRunCond expanded to false
> Errors-To:
> time-nuts-bounces+rk=timing-consultants.com+rk=timing-consultants.com at febo.c
> om
>
>
> In a message dated 7/16/2007 12:10:54 Pacific Daylight Time,
> SAIDJACK at aol.com writes:
>
>>For  example tilting the Cs unit by 90 degrees will typically give an
>>error
>
>>of about 1E-09 or so.
>
>>It would take some time for the  control loops to compensate for this
> error.
>
>
>
> Hi guys,
>
> I did tilt my 4050 when I first installed the unit, that number is from my
> memory. Notice that Magnus is right of course, the Cs will compensate the
> tilt,  given enough time to do so. I did not mean that the 1E-09 error
> will
> stay permanent of course, as I said in the follow-on sentence.
>
> Also the 4050 is not very well temperature compensated compared to modern
> units, I was not impressed when I saw the FTS tempco specifications. A
> good
> GPSDO can outperform the 4050.
>
> I have a military OCXO sample (new product) that is supposed to be
> "g-insensitive" and even that one has about E-09 frequency shift per 90
> degrees  tilt.
>
> One of the only ways to get around that is to use three crystals in
> series,
> with the three crystals oriented in the the XYZ axis, so their  errors
> compensate out.
>
> Vibration is also a big enemy of crystal oscillators of course.
>
> bye,
> Said
>
>
>
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