On Thu, April 20, 2006 7:25, Poul-Henning Kamp said:
And also, something else i don't understand: Why do
the newer GPS satellites rely on Rb standards rather
than Cs standards?
They last longer.
And they are less noisy and more stable, up to a day or so.
--
Björn
[Clocks in GPS satellites]
I said drift-free Rubidium :-)
They last longer.
I've seen comments about Rubidium having better short term stability than
Cesium.
What's short in that context?
How often do the ground stations talk to the satellites?
Is it reasonable to correct for the drift?
In message [EMAIL PROTECTED], Hal Murr
ay writes:
Is it reasonable to correct for the drift? If the drift is slow enough the
communication channel is already in place. It shouldn't be too much work for
the ground stations to track the frequency as well as position.
They have very complex
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- Original Message -
From: Christopher Hoover [EMAIL PROTECTED]
To: time-nuts@febo.com; [EMAIL PROTECTED]
Sent: Thursday, April 20, 2006 5:31 AM
Subject: Re: [time-nuts] How Rubidiums make their frequency (was
RE:time
and frequency measurement
Subject: Re: [time-nuts] How Rubidiums make their frequency (was
RE:time-nuts Digest, Vol 21, Issue 22)
On Thu, 20 Apr 2006 02:31:08 -0700, Christopher Hoover
[EMAIL PROTECTED] wrote:
Hi Tom,
That's a good explanation, thank you. I got that much already. (While it
took
Christopher Hoover asked:
one issue remains: i have to crank the magnetic field setting almost to
its high limit (9.91/10.00) to get 5 MHz out; lower settings give a
frequency that is too low. i presume this is unusual.
i have a rudimentary understanding of the rubidium
Since we can now make DDS's with arbitrary frequency resolution, could
you make an Rb oscillator without the magnetic field adjustment?
Wouldn't that reduce a source of error in frequency? Then we'd be
left with the ideal resonance frequency, right?
Are there any other influences on the
In message [EMAIL PROTECTED], Matt
Ettus writes:
Since we can now make DDS's with arbitrary frequency resolution, could
you make an Rb oscillator without the magnetic field adjustment?
Wouldn't that reduce a source of error in frequency? Then we'd be
left with the ideal resonance frequency,
From: Dave Brown [EMAIL PROTECTED]
Subject: Re: [time-nuts] How Rubidiums make their frequency
Date: Thu, 20 Apr 2006 09:13:08 +1200
Message-ID: [EMAIL PROTECTED]
- Original Message -
From: Matt Ettus [EMAIL PROTECTED]
To: [EMAIL PROTECTED]; Discussion of precise time and frequency
Hi..
In his message, Paul-Henning Kamp writes that a
drift-free standard has not been yet designed...
But Isn't Cesium drift-free? Since the SI second is
standardized as de duration of 9192631770 oscillation
of the hyperfine transition of the atom 133Cs?
If Cesium drifts, theren should be a
In message [EMAIL PROTECTED], Normand Martel
writes:
Hi..
In his message, Paul-Henning Kamp writes that a
drift-free standard has not been yet designed...
I said drift-free Rubidium :-)
And also, something else i don't understand: Why do
the newer GPS satellites rely on Rb standards rather
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