[ntp:questions] best gps receiver for time synchronization
David J Taylor
david-taylor at blueyonder.neither-this-bit.nor-this.co.uk
Tue Mar 10 18:18:21 UTC 2009
Unruh wrote:
[]
>> The newer "x" version appears to be a lot more sensitive, at the
>> expense of somewhat higher current consumption. You can tell the
>> LVC version what sentences to send. Better check the technical spec
>> to see what the USB one can be told to do:
>> http://www.garmin.com/manuals/GPS18x_TechnicalSpecifications.pdf
>
> Unfortnately, the LVC is a serial port output, plus a PPS output. The
> USB
> version has no PPS output and is liable to have pretty bad timing
> (where good=usec).
.. which is why I suggested checking in the manual as to whether the
output could be set to be a better determined length, which is what the OP
requested. It may be he /has/ to use USB.
By the way, while timing on USB may not be wonderful, I have an
application receiving some 40GB per day over USB, in fairly small packets
from a DVB satellite feed, and the buffering isn't that great (a few
kilobytes, I believe). Most often it's lossless, but it may be that the
error-correction in the stream-to-file software does a good job! <G>
Cheers,
David
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