[time-nuts] CSAC Project(was CSAC purchase)

Bob kb8tq kb8tq at n1k.org
Sat Jan 27 19:32:35 EST 2018


Yes, I have set up a CPU to dump all the data from a CSAC. Everything 
they list in their data sheet can easily be dumped via a standard UART 
interface. The serial protocol works exactly the way they describe. 

There is no “built in clock” so no ability to dump the time and date. You 
can “improve” the frequency stability by sending whatever you want to the 
tuning word. What you send and when you send it is entirely up to you. 
The real issue is having something more accurate than the CSAC to 
compare to when you do the frequency correction.


> On Jan 27, 2018, at 7:29 PM, Ronald Held <ronaldheld at gmail.com> wrote:
> Bob:
>    Interesting but too general for me. Has anyone used a CPU to read
> the CSAC outputs for time/date, and for improving frequency stability?
>            Ronald
> Hi
> “Included software” on the CSAC is a pretty short list …. There
> is not much past the “stuff” to set it on frequency and read out
> a few alarms.
> One thing that gets into a lot of these projects:
> We are Time Nuts and spec things in terms of time. This error
> over that period is some specific number. Maybe we look at
> temperature rather than sit it on the shelf for a year. The number
> is still a time error.
> Pretty much everybody making devices spec’s them (and may think
> of them) as frequency generating gizmos. They all spec a frequency
> error over some condition (like a period of time).  Unfortunately time
> error and frequency error aren’t the same thing.
> This also gets into things like control loops. Generally the input is a
> time error and the output is a frequency control. Same basic gotcha
> the input isn’t the same as the output. Fortunately they are related
> very closely to each other.
> Bob
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