[time-nuts] GHz output from fe5680a

beale beale at bealecorner.com
Mon Jan 30 19:48:16 EST 2012

What would you intend to do with the signal?

I'm not a microwave expert, but I believe the only microwave signals in the FE-5680A are the output of the step-recovery diode that multiplies the 60 MHz VCXO signal up to the 114th harmonic, plus that mixed with the 5.313 MHz DDS output to reach the Rb frequency. ( 114 * 60 Mhz - 5.313 Mhz -> 6.835 Ghz)   The SRD output would be just a mix of a lot of harmonics, not any sort of clean signal; I suspect the only real filter is the resonant cavity which is occupied by the Rb bulb.  I suppose a small enough probe into that cavity might not detune it too much, but you'd probably need an additional amplifier to do anything with that signal.  Iin this device the Rb vapor itself does not generate microwaves (like an active H maser), it just absorbs them, and it changes optically if the signal happens to be at the resonance frequency around 6.8 GHz.

>  -------Original Message-------
>  From: chris 0 <viscousplacebo at gmail.com>
>  Subject: [time-nuts] GHz output from fe5680a
>  I'm just wondering if its possible to tap into the GHz output from the rubidium in the fe5680a.

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