No subject

http://en.wikipedia.org/wiki/Parts-per_notation

ppt =3D parts per trillion. A change of one in 1,000,000,000.=20

Just like ppm or ppb, only smaller.

In this context at 10 MHz, 10 ppt would be a change of 0.0001 Hz.=20

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of SAL CORNACCHIA
Sent: Thursday, January 21, 2010 10:45 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] LPRO Pressure Sensitivity

Hi Bob,=20
Can You explain what 10 PPT stands for.
Thank You
=A0





________________________________
From: Bob Camp <lists at cq.nu>
To: Discussion of precise time and frequency measurement
<time-nuts at febo..com>
Sent: Thu, January 21, 2010 7:50:43 AM
Subject: Re: [time-nuts] LPRO Pressure Sensitivity

Hi

Yes indeed.=20

There really isn't a lot of data out there on pressure on rubidiums. Of
course we don't talk about it a lot on our data sheets either ...

If you accept that a normal day might have a 100 millibar change,=A0 =
That
changes the frequency 10 ppt, if the guess is right. At 10X that level =
it
would be as significant as temperature on a good unit. If it was that =
big it
should get a lot more attention ...

Bob


On Jan 21, 2010, at 4:53 AM, Magnus Danielson wrote:

> Bob Camp wrote:
>> Hi
>> Has anybody taken any data on LPRO's to see what their pressure
sensitivity is? I'm guessing it's=A0 ~ 0.1 ppt / millibar. That's only a =
guess
backed up by no data at all ....
>=20
> Do you mean 1E-13 per millibar? (I am only guessing)
>=20
> Cheers,
> Magnus
>=20
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
https://www..febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>=20


_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.