[time-nuts] motorola oncore descriptions

Didier Juges didier at cox.net
Thu Dec 14 01:09:06 UTC 2006


You have to be careful with the 10 kHz output. The output is only 
updated once per second (the 10,000 pulses in the 1 second period are 
equally spaced), so you still need the same filter as if you were using 
the 1 PPS output. I am not sure what the 10kHz output was intended to, 
but it's not that great of an advantage for phase locking a XO.

The only advantage I could see is if you are using a Jupiter to 
discipline a very lousy crystal oscillator, you could speed-up the lock 
by using a faster filter, then switch to a slower filter once lock is 
achieved. However, even though you will achieve lock faster, the 
precision will not be better (probably worse) than if you had a good 
OCXO to start with.

Didier KO4BB

Jason Rabel wrote:
>> Now, about the Rockwell Jupiter 8 boards...
>>
>> The TU30D140 is 5V powered (Antenna can be passive, 5V or 12V)
>> The TU30D160 is 3.3V powered (Antenna can be passive, 5V or 12V)
>>
>> Both boards have 10 KHz output. That's about it...
>>     
>
> Maybe I should clarify that one statement. I didn't mean they only have
> 10KHz outputs, I just meant that about it for your question. They also have
> a 1PPS output.
>
> With the 10KHz output you can build a poor man's GPS stabilized oscillator
> like here:
>
> http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm
>
> I actually just got in the parts for to build one of these the other day,
> probably going to try and assemble today. I'm using a Millren 5MHz VC OCXO
> that I got a while back. The advantage to the above design is the simplicity
> (and cost).
>
>
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