On Dec 11, 9:03 pm, "David J Taylor" <david-tay...@blueyonder.neither- this-part.nor-this-bit.co.uk> wrote: > dhavey wrote: > > [] > > > I am seeing 2000 - 4000 micro-second offsets from the serial port > > experiments. > > Here is a graph: > >http://cs.ucsb.edu/~dhavey/gps/offset.pdf > > I wouldn't worry about a couple of milliseconds, but I am surprised by how > much it seems to vary throughout the day - almost 3:1 from 1ms average at > 30,000 seconds to 3ms average at 65,000 seconds - if I'm reading your > graph correctly. Caused by other activity on that PC? Surely not by > temperature? > > David
I was using libserial to send the serial data. I think it may have been doing some buffering. I am using low level c functions now. I'm still seeing about 2000 usecs of offset but I don't know how much variance I will see throughout the day yet because I just finished writing it ;) I'll post a graph tomorrow with the results for today. _______________________________________________ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions