At 12:58 PM -0700 2009/05/19, Hal Murray wrote:
USB has a bad reputation, but I think it's way way overblown. Yes, it's polled, but that polling is done in hardware and the time scale is 1 ms. If you are satisfied with an accuracy of a few 10s of ms, USB works fine. The problem is the GPS unit.
And I can confirm that for my very un-scientific experiments I do get a pretty consistent time sync around 1 MS plus or minus mark from a USB serial port adapter in best case conditions. That's with no special work on a pretty stock consumer grade computer with an off the shelf USB to serial port.
Even my worst case machine where I expect horrible USB performance (busy USB 1.x port with other devices, and a CPU that runs at 100% busy for extended periods of time) I find I things never seem to go worse than +-50 ms. Not great, but much better than I was expecting based on some of the things I had read.
All my tests done with a time oriented GPS receiver. -- Russell _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
