[time-nuts] Disciplining Rubidium

Mike Feher mfeher at eozinc.com
Thu Apr 24 09:04:28 EDT 2008

I am not sure the floor would be the same. I expect it would be about 6
dB lower from what I remember. This is mostly due to the Q of the
resonator itself. As I recall, about 25 years ago when I was really
concerned about close in phase noise due to the low data rates concerned
and the multiplication up to 44 GHz, when we went from a 5 MHz to a 10
MHz oscillator the manufacturers wanted a 6 dB relief in the
specification. Also it seems to me in the early 70's, to the best of my
recollection, oscillators at around 3 MHz gave the best carrier to noise
ratio on a per hertz basis. - Mike

Mike B. Feher
EOZ Inc.
89 Arnold Blvd.
Howell, NJ, 07731
908-902-3831 - cell

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of John Ackermann N8UR
Sent: Thursday, April 24, 2008 8:21 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Disciplining Rubidium

John Miles wrote:
> Phase noise generally gets better with the higher-frequency OCXOs,
> I think the best of all possible worlds would be a 5-MHz OCXO like the
> you describe, being used to discipline a 10 MHz or higher-frequency
> -- john, KE5FX

I'm not sure about that -- at least, the Wenzel ULNs show better noise 
at small offsets for the 5 MHz than the 10 MHz versions (though the 
floor is the same).

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