[time-nuts] Re. DIY atomic "resonator" 6GHz synthesizer from ADI

[Richard (Rick) Karlquist]

You always want two frequency sources.  One generates a carrier
frequency offset many MHz from 6.834 GHz and the other frequency
source modulates the carrier with a sideband that is at the
exact ~6.834 GHz frequency that finds the atomic line.  The
sideband is in turn modulated with audio to find the exact
center of the line.  This is now the easiest section to
design.

This architecture automatically gives you gobs of resolution.
Of course you always have the C field for infinite resolution.
The other thing it does is prevent RF leaks from exciting the
atoms, since the strong LO is safely offset from 6.834.

Rick N6RK

On 4/11/2017 2:59 PM, paul swed wrote:
> When I read about the frequency generation in the Rb or CS there are
> normally many numbers associated with the actual frequency. Down to at
> least the 1 Hz level. Many of these PLLs are intended for multi-KHz steps.
> I speculate you might need 2 PLLs one thats very fine in I hz increments
> that gets added to something like these PLLs that step in 200 KHz
> increments.
> Regards
> Paul
> WB8TSL
>