[time-nuts] What’s the BEST crystal?

[Michael Wouters]

Hello Jim

>How does a CSO compare with a Mercury Ion clock - the latter does fit in
>a satellite and is intended to replace the USO kind of function.


The current CSOs can be surprisingly compact. I was visiting a university
colleague who had recently bought one from Cryoclock for use in quantum
computing experiments. The total package was about half a rack. One big
improvement has been moving to a closed cycle cooling system. It’s
difficult imagining it going into a spacecraft or satellite though.

Cheers
Michael

On Mon, 2 Mar 2020 at 2:40 am, jimlux <jimlux at earthlink.net> wrote:

> On 2/29/20 2:47 PM, Attila Kinali wrote:
> > On Sat, 29 Feb 2020 17:01:27 -0500
> > Bob kb8tq <kb8tq at n1k.org> wrote:
> >
> >>> Isn't that where "whispering gallery" modes come into the picture ?
> >>
> >> …… and done with sapphire.
> >>
> >> This is the real answer to “why is nobody going to do this?”. You
> already
> >> have something ( the sapphire resonators ) that does better than
> >> anything you could reasonably expect.
> >
> > It's the other way round. Yes, we have *a* solution for better phase
> noise
> > and stability, but not *the* solution. A CSO is a full size 19" rack
> > filled with equipment that needs constant maintenance. Nothing you can
> > put on a satellite, much less carry around. People wouldn't even put it
> > in cellphone base station, although they would love to have the
> additional
> > frequency stability and phase noise performance to squeeze in some
> > more customers into the limited frequency space.
>
>
> How does a CSO compare with a Mercury Ion clock - the latter does fit in
> a satellite and is intended to replace the USO kind of function.
>
> >
> > It is actually very hard to beat crystal oscillators and vapor cell
> > frequency standards in the stability/phase noise/size/power
> consumption/cost
> > trade-off. And until recently, quartz oscillators and vapor phase
> > standards occupied seperate areas in this trade-off space. Until the
> > CSAC came around and connected them.
> >
> >
> >                       Attila Kinali
> >
>
>
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