[time-nuts] Road-trip and rubidium fiddles

[Magnus Danielson]

On 04/09/2012 06:40 PM, Azelio Boriani wrote:
> Interesting, now two questions:
>
>> It is clear that the short term is limited by the instrument trigger
> jitter. A mixer pre->scaling is clearly needed.
>
> that is, a mixing to take down the 10MHz to a lower frequency? Mixing with
> a higher stability source?

As Attila so correctly commented, you use a Dual Mixer Time Difference 
solution to lower the measurement floor of a particular counter. You can 
also go below the noise of the transfer oscillator as it to some degree 
cancels in the cross correlation that the time difference measurement.

> And,
>> I also gave a quick tour of just how much you can read out of the clock's
> state and>status using the knob and voltmeter. Showing the locking in
> process and such.
> OK, my SR620 will arrive soon (it is actually in the Custom office to
> compute the duties) but this tells me that the SR620 can measure with high
> precision the incoming AC signal level? Why locking-in process? Has the
> SR620 to lock-in the input signal source?

That comment where not on the SR620 but on the HP5065A. Congratulations 
on the SR620, hope you will enjoy it. Make sure to use TimeLab alongside it.

> OK, maybe I have to study the SR620 manual first...

It's highly recommended regardless.

Cheers,
Magnus