[time-nuts] Re: Project Great

[Magnus Danielson]

Hi Jim,

Den 2021-11-28 kl. 01:26, skrev Lux, Jim:
>
> Not only is the CSAC low power (~ 100 mW) it's physically small, which 
> is attractive for some applications (inside a cubesat, for instance).  
> It used to be price competitive with a Rb, too ($1000-1500, as I 
> recall) but now they're about $5k.  Microsemi also has the NAC (which 
> is more a conventional Rb, but small)
>
>
> Parameter    NAC1        CSAC
> Aging        3E-10/mo    9E-10
>         1E-9/yr        10E-9
>
> ADEV        2E-11 @ 100sec    2.5E-11
> Â Â  Â Â Â Â  8E-11 @ 10Â Â Â  8E-11
>         2E-10 @ 1 sec    2.5E-10
>
> phase noise
> Â Â  Â Â Â Â  -86 @ 10Â Â Â  -70
> Â Â  Â Â Â Â  -120 @ 100Â Â Â  -113
> Â Â  Â Â Â Â  -138 @ 1000Â Â Â  -128
>         -143 @ 10k    -135
>         -148 @ 100k    -140
> Â Â  Â Â Â Â  -150Â Â Â  floor
>
> max chg        1E-9 (-20 to 65) 5E-10  (-10 to 35)
>
> pwr        1.2W op        0.12
>         1.8W warm    0.14
A good comparison.

In addition, for some application weight of the CSAC is also very 
attractive.

I'm not to say that CSAC is bad, but rather that one has to understand 
that it is a product intended for certain uses, and for those contexts 
it is a very interesting option, but outside of those contexts, there 
may simply be better suited options. It being "cesium" is not the magic 
keyword thought.

Cheers,
Magnus