On Thu, Jul 14, 2011 at 7:04 AM, unruh <un...@wormhole.physics.ubc.ca> wrote:
> Why? That native binary will also suffer from large latency (the serial link > is slow no matter what is being sent over it) and probably also fairly > large jitter. And it suffers from the huge downside of your having to > learn a whole new language. Those ASCII characters have to be assembled from internal binary data. Binary to ASCII conversion is not a fixed time process. for example the software might convert "3" faster then "57". And then some GPSes, I don't know about yours don't transmit leading zeroes so that sometimes the NEMA sentance is longer of shorter depending on the data values. Finally ASCII is MORE BYTES. so yes both are sent at 1200 bps but less data are sent if it does not need to be in ASCII and you avoid the conversion time. For example a floating point value is four bytes in binary and 8 or 9 in ASCII and therefor take half the time to send and zero time to convert. About the PPS being "dead on". How did you compare the PPS to the UTC second? I think you meant the period was one second as close as you could see by eye on the screen but the phase was unknown. At some point you will need to figure out the "fudge" number of the PPS otherwise your NTP time could be off. I'm not surprized that this is hard. You are setting up a stratum 1 NTP server in the ocean using some low-end equipment. That is outside of what people normally do and you'd expect to do some problem solving. -- Chris Albertson Redondo Beach, California _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
