On Mon, 24 Apr 2006 08:16:45 -0700, Franz wrote: > Richard, > thanks for the explanation. In theory it's clear now :) > > Is my calculation correct, when I multiply microseconds with (1000 / > 233) * 2^32 for decoding it in NTP format? (In this way I understood > the NTP FAQ 5.1.2.3.)
No, you should multiply seconds with 2^32. > So for 250 millisec it would be 4608334008583 That is 250 millisec = 0.25 sec => 1073741824 in NTP timestamp format. Binary this is 1000000000000000000000000000000, when adding leading zeros to get to a 32 bit number this is 01000000000000000000000000000000 . Now it's yor turn: - start with 1.5 seconds. - multiply by 2^32 - rewrite in binary - add leading zeros to get a 64 bit number - compare the result with the text in your original posting To mathematicians, this is normal. To mere mortals this is magic :) > > For vice versa I would multiply the NTP fraction part with 2^-32 and > then multiply it with 0.233 2^-32 seconds is *approximately* 0.233 nano seconds. Thus you should only multiply the fraction part by 2^-32. Never ever use the 0.233 nano seconds as you will end up with an error of nearly a milli second. > > Am I correct with these calculations? Not yet, a little more practice is needed so the theory fits with the practice. > > Thanks, Franz Regards, Johan Swenker _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
