[ntp:questions] Trimble Resolution T

Bill Unruh unruh at physics.ubc.ca
Sun Oct 16 19:18:19 UTC 2011


On Sun, 16 Oct 2011, Miguel Gonçalves wrote:

> On 16 October 2011 19:10, unruh <unruh at physics.ubc.ca> wrote:
>> In comp.protocols.time.ntp, you wrote:
>>> Hi!
>>>
>>> Anyone here used a Trimble Resolution T with NTP?
>>
>> From the pictures (all of the data sheets give a java error-- why in the
>> world they couldn't just deliver a pdf file I do not know) it would seem
>> that all it has is a PPS output on a coax cable. Thus you would want to
>> hook that up to your parallel or serial port and use on the PPS devices
>> to deliver the second mark to your computer. (gpsd, shmpps, kernel PPS)
>
> Thanks!
>
> I just opened the PDF data sheet in my safari browser in Mac OS X 10.7...

I guess they had problems today. A short while later I got a "page not
available" response instead of a java error.

>
> Anyway... PPS is easy... what about second numbering?

From some of the other documentation I could read, it appears that it does
deliver the seconds numbering over a usb connection. While usb is terrible for
accurate timing, since the timing requirement of the seconds numbering is only
about 1 second precision, usb should be fine. Now, I do not know what the
format is. If it is nmea then something like gpsd should be fine, and be able
to read both. If it is a proprietary protocol, then I have no idea. 
If you want to make use of the sawtooth correction (to get the time down to a
few nsec) then that will almost certainly be proprietary. However, if you are
feeding the timing into a computer, which you almost certainly are, it cannot
handle anything near ns anyway, and for usec, the uncorrected pulse should be
fine.

Just remember to terminate the line to your input with the termination
impedance of the cable you are using to get rid of ringing. While that ringing
should not cause troubles better to be safe.

>
> Cheers,
> Miguel
>

-- 
William G. Unruh   |  Canadian Institute for|     Tel: +1(604)822-3273
Physics&Astronomy  |     Advanced Research  |     Fax: +1(604)822-5324
UBC, Vancouver,BC  |   Program in Cosmology |     unruh at physics.ubc.ca
Canada V6T 1Z1     |      and Gravity       |  www.theory.physics.ubc.ca/


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