<snip> Stanley That application note will give you an introduction to metastability.
A pair of multi GHz D flipflops should ensure that the probability of metastability is less than once in a hundred years or longer. Just make sure you wait long enough for both the ECL and the extension counters to settle. A better method is to read a very long counter on the fly (64 bits or more) at the (synchronised) PPS edge. However with ripple counters this gets tricky as one has to sample each bit at suitable times to ensure that the sampled count is actually valid. Software extension of the count chain (after the PIC counter) is also possible. I'd just interpolate a 10MHz clock: you can do this all with a PIC and ADC and some inexpensive analog hardware. Bruce Thank you the pointers, I have found these explanations of interpolate : http://www.mwrf.com/Articles/ArticleID/12529/12529.html http://www.pendulum-instruments.com/Assets/download/timestamping_article.pdf As I understand it the trick is to measure the fractional parts of the wave at both the start and end or just the end if the start is synchronized, for a improvement in resolution at lower clock speeds. _______________________________________________ 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. ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ _______________________________________________ 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.