maximum-likelihood digit and DSYNC fixes from Dave Mills

bk: 47564401aucfcTXu6fR91zJoHnQWUw

diff --git a/ChangeLog b/ChangeLog
index dab00f289b8911e84fa0d5b53452c23d91d976ce..0e3dc3072573f2290fa7d2484dd729f2fc7fecee 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,4 @@
+* refclock_wwv.c: maximum-likelihood digit and DSYNC fixes from Dave Mills.
 * [Bug 967] preemptable associations are lost forever on a step.
 * ntp_config.c: [CID 48] missing "else" clause.
 * [Bug 833] ntpq config keyword is quote-mark unfriendly.

diff --git a/ntpd/refclock_wwv.c b/ntpd/refclock_wwv.c
index e126056cbc6db6c7d614ca652c44f3631d7f3ce1..2fb7b3e0c40e55dc53fccd96c4f75238338730a7 100644 (file)
--- a/ntpd/refclock_wwv.c
+++ b/ntpd/refclock_wwv.c
@@ -155,10 +155,10 @@
  * These bits indicate various alarm conditions, which are decoded to
  * form the quality character included in the timecode.
  */
-#define CMPERR         1       /* digit or misc bit compare error */
-#define LOWERR         2       /* low bit or digit amplitude or SNR */
-#define NINERR         4       /* less than nine digits in minute */
-#define SYNERR         8       /* not tracking second sync */
+#define CMPERR         0x1     /* digit or misc bit compare error */
+#define LOWERR         0x2     /* low bit or digit amplitude or SNR */
+#define NINERR         0x4     /* less than nine digits in minute */
+#define SYNERR         0x8     /* not tracking second sync */
 
 /*
  * Watchcat timeouts (watch)
@@ -465,7 +465,6 @@ char dstcod[] = {
 struct decvec {
        int radix;              /* radix (3, 4, 6, 10) */
        int digit;              /* current clock digit */
-       int mldigit;            /* maximum-likelihood digit */
        int count;              /* match count */
        double digprb;          /* max digit probability */
        double digsnr;          /* likelihood function (dB) */
@@ -2174,26 +2173,23 @@ wwv_corr4(
         * not considered correct until all nine clock digits have
         * reached threshold. This is intended as eye candy, but avoids
         * mistakes when the signal is low and the SNR is very marginal.
-        * once correctly set, the maximum-likelihood digit is ignored
-        * on the assumption the clock will always be correct unless for
-        * some reason it drifts to a different second.
         */
-       vp->mldigit = mldigit;
        if (vp->digprb < BTHR || vp->digsnr < BSNR) {
-               vp->count = 0;
                up->status |= BGATE;
        } else {
-               up->status |= DSYNC;
                if (vp->digit != mldigit) {
-                       vp->count = 0;
                        up->alarm |= CMPERR;
-                       if (!(up->status & INSYNC))
+                       if (vp->count > 0)
+                               vp->count--;
+                       if (vp->count == 0)
                                vp->digit = mldigit;
                } else {
                        if (vp->count < BCMP)
                                vp->count++;
-                       if (vp->count == BCMP)
+                       if (vp->count == BCMP) {
+                               up->status |= DSYNC;
                                up->digcnt++;
+                       }
                }
        }
        if ((pp->sloppyclockflag & CLK_FLAG4) && !(up->status &
@@ -2201,7 +2197,7 @@ wwv_corr4(
                sprintf(tbuf,
                    "wwv4 %2d %04x %3d %4d %5.0f %2d %d %d %d %5.0f %5.1f",
                    up->rsec - 1, up->status, up->gain, up->yepoch,
-                   up->epomax, vp->radix, vp->digit, vp->mldigit,
+                   up->epomax, vp->radix, vp->digit, mldigit,
                    vp->count, vp->digprb, vp->digsnr);
                record_clock_stats(&peer->srcadr, tbuf);
 #ifdef DEBUG