[time-nuts] Zeeman Audio Source?

Tom Van Baak tvb at leapsecond.com
Wed Jan 12 17:28:22 EST 2005


42.82 kHz is what you want. It's the same for
the Cs tubes I know about and is related to the
distance between the multiple peaks in the Cs
resonance; the so-called Zeeman splitting.

See some photos of the seven Cs peaks at:
http://www.leapsecond.com/pages/cspeak/
or the huge image at:
http://www.leapsecond.com/pages/cfield/

It needs to be relatively stable -- one source I
read says a one percent error in Zeeman input
frequency corresponds to a 3.6e-12 error in Cs
frequency. Any old cheap quartz based signal
generator should do; you can use a frequency
counter to monitor the signal generator output
frequency.

/tvb

----- Original Message -----
From: "Brooke Clarke" <brooke at pacific.net>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: Wednesday, January 12, 2005 14:09
Subject: Re: [time-nuts] Zeeman Audio Source?


> Hi:
>
> I tried to use my HP 204B audio source for the Zeeman test, but although
it puts out over 5 volts RMS into an open circuit, the voltage across the 50
Ohm FTS4060 Zeeman input is only 0.33 Volts, not the 1 Volt needed.  Can
someone recommend an audio generator, hopefully available for a reasonable
price somewhere?
>
> The HP manual says the frequency should be 42.82 kHz for zero offset.
There is a table listing a number of other frequencies that give different
offsets.  This was back in the days when a second got a new definition each
year, hence the different offsets, but today zero offset is the standard.
>
> Have Fun,
>
> Brooke Clarke, N6GCE
> --
> w/Java http://www.PRC68.com
> w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
> http://www.precisionclock.com
>
>
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