ntp/ntpd/refclock_wwv.c

84 #define WWV_SEC		8000	/* second epoch (sample rate) (Hz) */
85 #define WWV_MIN		(WWV_SEC * 60) /* minute epoch */
133 #define MSYNC		0x0001	/* minute epoch sync */
134 #define SSYNC		0x0002	/* second epoch sync */
481 	double	epoch;		/* accumulated epoch differences */
486 	long	mepoch;		/* minute synch epoch */
536 	int	yepoch;		/* sync epoch */
537 	int	repoch;		/* buffered sync epoch */
896  * quadrature phase. The routine also determines the minute synch epoch,
900  * logical clock samples spanning exactly one second. The epoch ramp
903  * during the epoch ramp.
969 	static int epopos;	/* epoch second sync position buffer */
972 	int	epoch;		/* comb filter index */
1091 	 * while the second counter (epoch) counts the samples in the
1095 	epoch = up->mphase % WWV_SEC;
1174 			 * If the leap bit is set, set the minute epoch
1188 	 * counter matches the minute epoch within the second, the
1190 	 * the remaining seconds until the next minute epoch, while the
1191 	 * sync epoch is zero. Watch out for the first second; if
1192 	 * already synchronized to the second, the buffered sync epoch
1205 		if (sp->metric >= TTHR && epoch == sp->mepoch % WWV_SEC)
1212 				up->repoch = up->yepoch = epoch;
1246 	dtemp = (epobuf[epoch] += (mfsync - epobuf[epoch]) /
1252 		epopos = epoch;
1253 		j = epoch - 6 * MS;
1258 	if (epoch == 0) {
1289  * difference between the current and previous epoch must be less than
1292  * epoch.
1304 	long	epoch;
1311 	 * epoch. Accumulate all samples to determine the total noise
1314 	epoch = up->mphase - pdelay - SYNSIZ;
1315 	if (epoch < 0)
1316 		epoch += WWV_MIN;
1319 		sp->pos = epoch;
1324 	 * At the end of the minute, determine the epoch of the minute
1336 		epoch = (sp->pos - sp->lastpos) % WWV_MIN;
1341 			if (labs(epoch) < AWND * MS) {
1358 			    sp->synsnr, sp->pos % WWV_SEC, epoch);
1374  * determines the second sync epoch position within the second and
1385 	int epopos		/* epoch max position */
1390 	static int epoch_mf[3]; /* epoch median filter */
1391 	static int tepoch;	/* current second epoch */
1392  	static int xepoch;	/* last second epoch */
1393  	static int zepoch;	/* last run epoch */
1398 	static int mepoch;	/* longest run end epoch */
1432 	 * epoch.
1455 	 * If the epoch candidate is the same as the last one, increment
1456 	 * the run counter. If not, save the length, epoch and end
1458 	 * The epoch is considered valid if the run is at least SCMP
1460 	 * last epoch  is not greater than the averaging interval. Thus,
1502 	 * interval the candidate epoch at the end of the longest run is
1504 	 * interval are different, so the candidate epoch is the current
1505 	 * epoch. The frequency update is computed from the candidate
1506 	 * epoch difference (125-us units) and time difference (seconds)
1595  * wwv_epoch - epoch scanner
1598  * scans the receiver second epoch to determine the signal amplitudes
1629 	 * and station mitigation. Also set the seconds epoch at 800 ms
1631 	 * the epoch backwards.
1642 	 * Use the signal amplitude at epoch 15 ms as the noise floor.
1648 	 * epoch is not exact.
1685 	 * adjust the codec gain. Note the epoch is buffered from the
1687 	 * seconds synch is diddling the epoch. Then, determine the true
2043  * loss, the minute sync epoch will be in the same second. This requires