Tom, Thanks for the feedback!
On 6 February 2018 at 20:29, Tom Van Baak <t...@leapsecond.com> wrote: > > 2) Not all decoding errors are equal. Since this is a time code instead of > arbitrary binary data you can use the internal structure of the data to > your benefit. > As I said to Poul-Henning, that is the next level of error detection, which also has application in error correcting some of the "almost-right" signals. > 3) A side-effect of your data set is that you can track performance of the > oscillator inside the logic analyzer: convert the 700k GPS timestamps into > interval, find and replace the 4 glitch lines with 2 lines of 1.000150, and > then use Stable32 or TimeLab to plot. I used a 10 minute running average to > reduce the 50 us quantization noise. Note the mean frequency of your > timebase is 152 ppm low. I made it out to be 152.2ppm, which is kinda disappointing. But the signal analyser cost very little, and you get what you pay for. I have not yet wrapped my head around how to create ADEV plots, so thanks for your work on that - it's interesting to see that (presumed) initial thermal effect. > Over 8 days this results in a cumulative sampling error of 105 seconds. If > your decoding algorithms are relative instead of absolute this won't be a > problem. OTOH, you may be able to use your decoding process to detect this > drift and then compensate for it in software. You have the beginnings of a > MSF-Disciplined-Oscillator project. > MSF disciplined oscillator?! I don't trust these receivers to any better than about the 20ms mark, so such a disciplined oscillator would have quite a long integration time! Thanks again. _______________________________________________ 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.