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iovane@inwind.it

Wed, Apr 23, 2008 10:11 PM

Does it make any sense "GPS disciplining" a rubidium oscillator?
In such a case we have a chain made of
GPS - Rubidium - XTAL
as opposed to the simpler case of
GPS - XTAL
(assume that XTALs are of the same quality, and so the control loops).
Does the addition of Rb in the middle of the chain add
any real advantages?

Antonio I8IOV

Does it make any sense "GPS disciplining" a rubidium oscillator? In such a case we have a chain made of GPS - Rubidium - XTAL as opposed to the simpler case of GPS - XTAL (assume that XTALs are of the same quality, and so the control loops). Does the addition of Rb in the middle of the chain add any real advantages? Antonio I8IOV

DI

David I. Emery

Wed, Apr 23, 2008 10:54 PM

On Thu, Apr 24, 2008 at 12:11:16AM +0200, iovane@inwind.it wrote:

Does it make any sense "GPS disciplining" a rubidium oscillator?
In such a case we have a chain made of
GPS - Rubidium - XTAL
as opposed to the simpler case of
GPS - XTAL
(assume that XTALs are of the same quality, and so the control loops).
Does the addition of Rb in the middle of the chain add
any real advantages?

Holdover...

--
Dave Emery N1PRE/AE, die@dieconsulting.com DIE Consulting, Weston, Mass 02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in
celebration of what could have been, but wasn't and is not to be now either."

On Thu, Apr 24, 2008 at 12:11:16AM +0200, iovane@inwind.it wrote: > Does it make any sense "GPS disciplining" a rubidium oscillator? > In such a case we have a chain made of > GPS - Rubidium - XTAL > as opposed to the simpler case of > GPS - XTAL > (assume that XTALs are of the same quality, and so the control loops). > Does the addition of Rb in the middle of the chain add > any real advantages? Holdover... -- Dave Emery N1PRE/AE, die@dieconsulting.com DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either."

TD

Tom Duckworth

Wed, Apr 23, 2008 11:12 PM

Antonio,

Absolutely! With a good XTAL you have parts in the 9th, short term. With a
XTAL controlled by a Rubidium, in the phase-lock feedback loop, you have
parts in the 12th, short term. With the Rubidium disciplined by the GPS,
with its on-board Rubidium/Cesium oscillators updated from the ground every
orbit, you have parts in the 14th, short term. In other words, your
XTAL/Rubidium/GPS has an effective short-term Allen variance equivalent to a
good Cesium; and better than a single Cesium, long term, for a lot less
money!

Tom
Tom Duckworth
510-886-1396

-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of iovane@inwind.it
Sent: Wednesday, April 23, 2008 3:11 PM
To: time-nuts
Subject: [time-nuts] Disciplining Rubidium

Does it make any sense "GPS disciplining" a rubidium oscillator?
In such a case we have a chain made of
GPS - Rubidium - XTAL
as opposed to the simpler case of
GPS - XTAL
(assume that XTALs are of the same quality, and so the control loops).
Does the addition of Rb in the middle of the chain add
any real advantages?

Antonio I8IOV

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Antonio, Absolutely! With a good XTAL you have parts in the 9th, short term. With a XTAL controlled by a Rubidium, in the phase-lock feedback loop, you have parts in the 12th, short term. With the Rubidium disciplined by the GPS, with its on-board Rubidium/Cesium oscillators updated from the ground every orbit, you have parts in the 14th, short term. In other words, your XTAL/Rubidium/GPS has an effective short-term Allen variance equivalent to a good Cesium; and better than a single Cesium, long term, for a lot less money! Tom Tom Duckworth 510-886-1396 -----Original Message----- From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On Behalf Of iovane@inwind.it Sent: Wednesday, April 23, 2008 3:11 PM To: time-nuts Subject: [time-nuts] Disciplining Rubidium Does it make any sense "GPS disciplining" a rubidium oscillator? In such a case we have a chain made of GPS - Rubidium - XTAL as opposed to the simpler case of GPS - XTAL (assume that XTALs are of the same quality, and so the control loops). Does the addition of Rb in the middle of the chain add any real advantages? Antonio I8IOV _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.

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Disciplining Rubidium