[time-nuts] Disciplining Rubidium

Tom Duckworth tomduck at comcast.net
Wed Apr 23 19:12:43 EDT 2008


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

Tom Duckworth
-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of iovane at 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 
(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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