[time-nuts] GPDSO is working

Bob Stewart bob at evoria.net
Fri Jul 12 15:49:28 UTC 2013


Hi Azelio


I'm not tracking it with a counter.   The VE2ZAZ board I mentioned in my post has a serial port interface.  Every 32 seconds you get a line of tracking information, which includes the right 4 digits of the hex count of how many oscillator transitions occurred during the previous 16 second sampling period.  With an oscillator of 10 MHz there will be 160,000,000 transitions during the 10 second sampling period for a dead accurate oscillator.  It also gives an error count for each period so you don't have to do the math to subtract it.  This error count value is the one I'm referring to.


Bob - AE6RV




>________________________________
> From: Azelio Boriani <azelio.boriani at screen.it>
>To: Discussion of precise time and frequency measurement <time-nuts at febo.com> 
>Sent: Friday, July 12, 2013 3:50 AM
>Subject: Re: [time-nuts] GPDSO is working
> 
>
>No, it doesn't depend on the timing mode. What reference are you
>using? That is, your counter is using its internal reference or else.
>
>On Fri, Jul 12, 2013 at 5:59 AM, Bob Stewart <bob at evoria.net> wrote:
>> After ham-fistedly breaking a few things, I've finally got my GPSDO working. (does happy dance)  Now that it's had some time to warm up I see that it's started wandering around +/- a couple of counts from sample to sample (16 seconds).  Is this because the UT+ is not set to timing mode?  Putting in an RS-232 (or USB) to TTL adapter, switchable between the UT+ and the VE2ZAZ board, is pretty much next on my schedule.  I've got an adapter I made many years ago, but it's not suitable for mounting in the box, and there's no simple way to hook it up to the UT+ at the moment.
>>
>> Bob
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