[App_rpt-users] RTCM voter problem - SOLVED

[Chuck Henderson]

The timing of one second comes from the GPS satellites and is accurate.
Chuck

On Sat, Apr 9, 2016 at 7:03 PM, Joe Leikhim <rhyolite at leikhim.com> wrote:

> According to the original documentation for the first generation X1 is a
> SER3418-ND 9.60MHz 18pf 30ppm.
>
> So 9.6 x (+/-) 30 = +/- 288 Hz.
>
> My question is If the same processor is doing the A/D conversion AND
> checking the number of samples/second why would there be a discrepancy
> regardless of the timing offset? Or is the error at the receiving end??
>
>
>
>
> On 4/9/2016 2:16 PM, James Cizek wrote:
>
> Sure Willem,  in voter.c, the stock line is:
>
> if ((samplecnt >= 7999) && (samplecnt <= 8001))
>
> it needs to be changed to something like:
>
> if ((samplecnt >= 7999) && (samplecnt <= 8003 ))
>
> That was just enough to make my first RTCM work.  I've had a chance now to
> check a few more of my RTCMs on the bench this morning and the crystal
> frequencies are kind of all over.  The next one I had on the bench was
> 5.2Khz fast.  The above code was still not enough to fix it (as would be
> expected) so it looks like the quality control on whatever manufacturer
> that crystal is, isn't very good (or a low tolerance crystal is being
> used).  I am going to pursue crystal replacement to get a highly accurate,
> stable, on-frequency crystal in there as my first choice.  Changing the
> firmware 5 different times doesn't seem like the right answer.
>
> Jim put that sanity check in there for a reason.  Working around it *may*
> allow the device to work, but to me, it seems getting the hardware
> operating the way it was supposed to originally is the better answer.  I
> will follow up with Micro-node and let you all know how it goes.
>
> Thanks.
>
> James
> KI0KN
>
> On Sat, Apr 9, 2016 at 9:05 AM, Willem Schreuder <willem at prinmath.com>
> wrote:
>
>> On Sat, 9 Apr 2016, James Cizek wrote:
>>
>> Jim helped adjust the code to be more tolerant of the sampling error and
>>> my whole system instantly worked.
>>>
>>
>> Could you please share the code adjustment for future reference.
>>
>> ================================================================
>> Dr. Willem A. Schreuder,  President,  Principia Mathematica
>> Address:  445 Union Blvd, Suite 230,  Lakewood, CO  80228, USA
>> Tel: (303) 716-3573   Fax: (303) 716-3575
>> WWW: www.prinmath.com   Email: <Willem.Schreuder at prinmath.com>
>> Willem.Schreuder at prinmath.com
>>
>
>
>
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>
> --
> Joe Leikhim
>
>
> Leikhim and Associates
>
> Communications Consultants
>
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> JLeikhim at Leikhim.com
> 407-982-0446
> WWW.LEIKHIM.COM
>
>
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