diff options
Diffstat (limited to 'contrib/ntp/ntpd/refclock_irig.c')
| -rw-r--r-- | contrib/ntp/ntpd/refclock_irig.c | 47 |
1 files changed, 23 insertions, 24 deletions
diff --git a/contrib/ntp/ntpd/refclock_irig.c b/contrib/ntp/ntpd/refclock_irig.c index 0b35368..6be09d9 100644 --- a/contrib/ntp/ntpd/refclock_irig.c +++ b/contrib/ntp/ntpd/refclock_irig.c @@ -116,13 +116,14 @@ * timestamp in NTP format. * * The fraction part of the on-time timestamp is a good indicator of how - * well the driver is doing. With an UltrSPARC 30 and Solaris 2.7, this - * thing can keep the clock within a few tens of microseconds relative - * to the IRIG-B signal. Accuracy with IRIG-E is about ten times worse. - * Unfortunately, Sun broke the 2.7 audio driver in 2.8, which has a - * 10-ms sawtooth modulation. The driver attempts to remove the - * modulation by some clever estimation techniques which mostly work. - * Your experience may vary. + * well the driver is doing. Once upon a time, an UltrSPARC 30 and + * Solaris 2.7 kept the clock within a few tens of microseconds relative + * to the IRIG-B signal. Accuracy with IRIG-E was about ten times worse. + * Unfortunately, Sun broke the 2.7 audio driver in 2.8, which has a 10- + * ms sawtooth modulation. The driver attempts to remove the modulation + * by some clever estimation techniques which mostly work. With the + * "mixerctl -o" command before starting the daemon, the jitter is down + * to about 100 microseconds. Your experience may vary. * * Unlike other drivers, which can have multiple instantiations, this * one supports only one. It does not seem likely that more than one @@ -132,13 +133,12 @@ * Fudge factors * * Fudge flag4 causes the dubugging output described above to be - * recorded in the clockstats file. When the audio driver is compiled, - * fudge flag2 selects the audio input port, where 0 is the mike port - * (default) and 1 is the line-in port. It does not seem useful to - * select the compact disc player port. Fudge flag3 enables audio - * monitoring of the input signal. For this purpose, the monitor gain is - * set to a default value. Fudgetime2 is used as a frequency vernier for - * broken codec sample frequency. + * recorded in the clockstats file. Fudge flag2 selects the audio input + * port, where 0 is the mike port (default) and 1 is the line-in port. + * It does not seem useful to select the compact disc player port. Fudge + * flag3 enables audio monitoring of the input signal. For this purpose, + * the monitor gain is set to a default value. Fudgetime2 is used as a + * frequency vernier for broken codec sample frequency. */ /* * Interface definitions @@ -157,7 +157,7 @@ #define FIELD 10 /* subfields per field */ #define MINTC 2 /* min PLL time constant */ #define MAXTC 20 /* max PLL time constant max */ -#define MAXSIG 6000. /* maximum signal level */ +#define MAXAMP 6000. /* maximum signal level */ #define MAXCLP 100 /* max clips above reference per s */ #define DRPOUT 100. /* dropout signal level */ #define MODMIN 0.5 /* minimum modulation index */ @@ -442,15 +442,15 @@ irig_receive( sample = up->comp[~*dpt++ & 0xff]; /* - * Clip noise spikes greater than MAXSIG. If no clips, + * Clip noise spikes greater than MAXAMP. If no clips, * increase the gain a tad; if the clips are too high, * decrease a tad. */ - if (sample > MAXSIG) { - sample = MAXSIG; + if (sample > MAXAMP) { + sample = MAXAMP; up->clipcnt++; - } else if (sample < -MAXSIG) { - sample = -MAXSIG; + } else if (sample < -MAXAMP) { + sample = -MAXAMP; up->clipcnt++; } @@ -690,6 +690,7 @@ irig_base( */ if (up->carphase != 7) return; + env = (up->lastenv[2] - up->lastenv[6]) / 2.; lope = (up->lastint[2] - up->lastint[6]) / 2.; if (lope > up->intmax) @@ -939,11 +940,8 @@ irig_decode( else pp->leap = LEAP_NOWARNING; up->second = (up->second + up->decim) % 60; - if (pp->year > 0) { + if (pp->year > 0) pp->year += 2000; - if (syncchar == '0') - up->errflg |= IRIG_ERR_CHECK; - } if (pp->second != up->second) up->errflg |= IRIG_ERR_CHECK; up->second = pp->second; @@ -993,6 +991,7 @@ irig_poll( if (pp->coderecv == pp->codeproc) { refclock_report(peer, CEVNT_TIMEOUT); return; + } else { refclock_receive(peer); record_clock_stats(&peer->srcadr, pp->a_lastcode); |
