diff options
Diffstat (limited to 'ntpd/refclock_chu.c')
| -rw-r--r-- | ntpd/refclock_chu.c | 699 |
1 files changed, 346 insertions, 353 deletions
diff --git a/ntpd/refclock_chu.c b/ntpd/refclock_chu.c index 843e9aaa4079..ca14dc600fb4 100644 --- a/ntpd/refclock_chu.c +++ b/ntpd/refclock_chu.c @@ -26,47 +26,47 @@ #ifdef ICOM #include "icom.h" #endif /* ICOM */ - /* * Audio CHU demodulator/decoder * * This driver synchronizes the computer time using data encoded in * radio transmissions from Canadian time/frequency station CHU in * Ottawa, Ontario. Transmissions are made continuously on 3330 kHz, - * 7335 kHz and 14670 kHz in upper sideband, compatible AM mode. An + * 7850 kHz and 14670 kHz in upper sideband, compatible AM mode. An * ordinary shortwave receiver can be tuned manually to one of these * frequencies or, in the case of ICOM receivers, the receiver can be - * tuned automatically using this program as propagation conditions - * change throughout the day and night. + * tuned automatically as propagation conditions change throughout the + * day and season. * - * The driver receives, demodulates and decodes the radio signals when - * connected to the audio codec of a suported workstation hardware and - * operating system. These include Solaris, SunOS, FreeBSD, NetBSD and - * Linux. In this implementation, only one audio driver and codec can be - * supported on a single machine. + * The driver requires an audio codec or sound card with sampling rate 8 + * kHz and mu-law companding. This is the same standard as used by the + * telephone industry and is supported by most hardware and operating + * systems, including Solaris, SunOS, FreeBSD, NetBSD and Linux. In this + * implementation, only one audio driver and codec can be supported on a + * single machine. * * The driver can be compiled to use a Bell 103 compatible modem or * modem chip to receive the radio signal and demodulate the data. * Alternatively, the driver can be compiled to use the audio codec of - * the Sun workstation or another with compatible audio drivers. In the + * the workstation or another with compatible audio drivers. In the * latter case, the driver implements the modem using DSP routines, so * the radio can be connected directly to either the microphone on line * input port. In either case, the driver decodes the data using a - * maximum likelihood technique which exploits the considerable degree + * maximum-likelihood technique which exploits the considerable degree * of redundancy available to maximize accuracy and minimize errors. * * The CHU time broadcast includes an audio signal compatible with the - * Bell 103 modem standard (mark = 2225 Hz, space = 2025 Hz). It consist - * of nine, ten-character bursts transmitted at 300 bps and beginning - * each second from second 31 to second 39 of the minute. Each character - * consists of eight data bits plus one start bit and two stop bits to - * encode two hex digits. The burst data consist of five characters (ten - * hex digits) followed by a repeat of these characters. In format A, - * the characters are repeated in the same polarity; in format B, the - * characters are repeated in the opposite polarity. + * Bell 103 modem standard (mark = 2225 Hz, space = 2025 Hz). The signal + * consists of nine, ten-character bursts transmitted at 300 bps between + * seconds 31 and 39 of each minute. Each character consists of eight + * data bits plus one start bit and two stop bits to encode two hex + * digits. The burst data consist of five characters (ten hex digits) + * followed by a repeat of these characters. In format A, the characters + * are repeated in the same polarity; in format B, the characters are + * repeated in the opposite polarity. * * Format A bursts are sent at seconds 32 through 39 of the minute in - * hex digits + * hex digits (nibble swapped) * * 6dddhhmmss6dddhhmmss * @@ -96,10 +96,10 @@ * By design, the last stop bit of the last character in the burst * coincides with 0.5 second. Since characters have 11 bits and are * transmitted at 300 bps, the last stop bit of the first character - * coincides with 0.5 - 10 * 11/300 = 0.133 second. Depending on the - * UART, character interrupts can vary somewhere between the beginning - * of bit 9 and end of bit 11. These eccentricities can be corrected - * along with the radio propagation delay using fudge time 1. + * coincides with 0.5 - 9 * 11/300 = 0.170 second. Depending on the + * UART, character interrupts can vary somewhere between the end of bit + * 9 and end of bit 11. These eccentricities can be corrected along with + * the radio propagation delay using fudge time 1. * * Debugging aids * @@ -107,11 +107,15 @@ * data helpful in diagnosing problems with the radio signal and serial * connections. With debugging enabled (-d on the ntpd command line), * the driver produces one line for each burst in two formats - * corresponding to format A and B. Following is format A: + * corresponding to format A and B.Each line begins with the format code + * chuA or chuB followed by the status code and signal level (0-9999). + * The remainder of the line is as follows. + * + * Following is format A: * * n b f s m code * - * where n is the number of characters in the burst (0-11), b the burst + * where n is the number of characters in the burst (0-10), b the burst * distance (0-40), f the field alignment (-1, 0, 1), s the * synchronization distance (0-16), m the burst number (2-9) and code * the burst characters as received. Note that the hex digits in each @@ -119,43 +123,50 @@ * * 10 38 0 16 9 06851292930685129293 * - * is interpreted as containing 11 characters with burst distance 38, + * is interpreted as containing 10 characters with burst distance 38, * field alignment 0, synchronization distance 16 and burst number 9. * The nibble-swapped timecode shows day 58, hour 21, minute 29 and * second 39. * - * When the audio driver is compiled, format A is preceded by - * the current gain (0-255) and relative signal level (0-9999). The - * receiver folume control should be set so that the gain is somewhere - * near the middle of the range 0-255, which results in a signal level - * near 1000. - * * Following is format B: * * n b s code * - * where n is the number of characters in the burst (0-11), b the burst + * where n is the number of characters in the burst (0-10), b the burst * distance (0-40), s the synchronization distance (0-40) and code the * burst characters as received. Note that the hex digits in each * character are reversed and the last ten digits inverted, so the burst * - * 11 40 1091891300ef6e76ecff + * 10 40 1091891300ef6e76ec * - * is interpreted as containing 11 characters with burst distance 40. + * is interpreted as containing 10 characters with burst distance 40. * The nibble-swapped timecode shows DUT1 +0.1 second, year 1998 and TAI * - UTC 31 seconds. * + * Each line is preceeded by the code chuA or chuB, as appropriate. If + * the audio driver is compiled, the current gain (0-255) and relative + * signal level (0-9999) follow the code. The receiver volume control + * should be set so that the gain is somewhere near the middle of the + * range 0-255, which results in a signal level near 1000. + * * In addition to the above, the reference timecode is updated and * written to the clockstats file and debug score after the last burst * received in the minute. The format is * - * qq yyyy ddd hh:mm:ss nn dd tt + * sq yyyy ddd hh:mm:ss l s dd t agc ident m b * - * where qq are the error flags, as described below, yyyy is the year, - * ddd the day, hh:mm:ss the time of day, nn the number of format A - * bursts received during the previous minute, dd the decoding distance - * and tt the number of timestamps. The error flags are cleared after - * every update. + * s '?' before first synchronized and ' ' after that + * q status code (see below) + * yyyy year + * ddd day of year + * hh:mm:ss time of day + * l leap second indicator (space, L or D) + * dst Canadian daylight code (opaque) + * t number of minutes since last synchronized + * agc audio gain (0 - 255) + * ident identifier (CHU0 3330 kHz, CHU1 7850 kHz, CHU2 14670 kHz) + * m signal metric (0 - 100) + * b number of timecodes for the previous minute (0 - 59) * * Fudge factors * @@ -184,6 +195,11 @@ * 9600 bps if the high order 0x80 bit of the mode is zero and 1200 bps * if one. The C-IV trace is turned on if the debug level is greater * than one. + * + * Alarm codes + * + * CEVNT_BADTIME invalid date or time + * CEVNT_PROP propagation failure - no stations heard */ /* * Interface definitions @@ -194,8 +210,8 @@ #define DEVICE "/dev/chu%d" /* device name and unit */ #define SPEED232 B300 /* UART speed (300 baud) */ #ifdef ICOM -#define TUNE .001 /* offset for narrow filter (kHz) */ -#define DWELL 5 /* minutes in a probe cycle */ +#define TUNE .001 /* offset for narrow filter (MHz) */ +#define DWELL 5 /* minutes in a dwell */ #define NCHAN 3 /* number of channels */ #define ISTAGE 3 /* number of integrator stages */ #endif /* ICOM */ @@ -210,6 +226,7 @@ #define SIZE 256 /* decompanding table size */ #define MAXAMP 6000. /* maximum signal level */ #define MAXCLP 100 /* max clips above reference per s */ +#define SPAN 800. /* min envelope span */ #define LIMIT 1000. /* soft limiter threshold */ #define AGAIN 6. /* baseband gain */ #define LAG 10 /* discriminator lag */ @@ -224,23 +241,28 @@ * Decoder definitions */ #define CHAR (11. / 300.) /* character time (s) */ -#define FUDGE .185 /* offset to first stop bit (s) */ #define BURST 11 /* max characters per burst */ #define MINCHAR 9 /* min characters per burst */ #define MINDIST 28 /* min burst distance (of 40) */ -#define MINBURST 4 /* min bursts in minute */ #define MINSYNC 8 /* min sync distance (of 16) */ #define MINSTAMP 20 /* min timestamps (of 60) */ -#define METRIC 50. /* min channel metric */ -#define PANIC 1440 /* panic timeout (m) */ -#define HOLD 30 /* reach hold (m) */ +#define MINMETRIC 50 /* min channel metric (of 160) */ /* - * Hex extension codes (>= 16) + * The on-time synchronization point for the driver is the last stop bit + * of the first character 170 ms. The modem delay is 0.8 ms, while the + * receiver delay is approxmately 4.7 ms at 2125 Hz. The fudge value 1.3 + * ms due to the codec and other causes was determined by calibrating to + * a PPS signal from a GPS receiver. The additional propagation delay + * specific to each receiver location can be programmed in the fudge + * time1. + * + * The resulting offsets with a 2.4-GHz P4 running FreeBSD 6.1 are + * generally within 0.5 ms short term with 0.3 ms jitter. The long-term + * offsets vary up to 0.3 ms due to ionospheric layer height variations. + * The processor load due to the driver is 0.4 percent. */ -#define HEX_MISS 16 /* miss _ */ -#define HEX_SOFT 17 /* soft error * */ -#define HEX_HARD 18 /* hard error = */ +#define PDELAY ((170 + .8 + 4.7 + 1.3) / 1000) /* system delay (s) */ /* * Status bits (status) @@ -256,6 +278,7 @@ #define AVALID 0x0100 /* valid A frame */ #define BVALID 0x0200 /* valid B frame */ #define INSYNC 0x0400 /* clock synchronized */ +#define METRIC 0x0800 /* one or more stations heard */ /* * Alarm status bits (alarm) @@ -273,12 +296,13 @@ #ifdef HAVE_AUDIO /* - * Maximum likelihood UART structure. There are eight of these + * Maximum-likelihood UART structure. There are eight of these * corresponding to the number of phases. */ struct surv { - double shift[12]; /* mark register */ - double es_max, es_min; /* max/min envelope signals */ + l_fp cstamp; /* last bit timestamp */ + double shift[12]; /* sample shift register */ + double span; /* shift register envelope span */ double dist; /* sample distance */ int uart; /* decoded character */ }; @@ -301,19 +325,19 @@ struct xmtr { * CHU unit control structure */ struct chuunit { - u_char decode[20][16]; /* maximum likelihood decoding matrix */ + u_char decode[20][16]; /* maximum-likelihood decoding matrix */ l_fp cstamp[BURST]; /* character timestamps */ l_fp tstamp[MAXSTAGE]; /* timestamp samples */ l_fp timestamp; /* current buffer timestamp */ l_fp laststamp; /* last buffer timestamp */ l_fp charstamp; /* character time as a l_fp */ + int second; /* counts the seconds of the minute */ int errflg; /* error flags */ int status; /* status bits */ char ident[5]; /* station ID and channel */ #ifdef ICOM int fd_icom; /* ICOM file descriptor */ - int chan; /* data channel */ - int achan; /* active channel */ + int chan; /* radio channel */ int dwell; /* dwell cycle */ struct xmtr xmtr[NCHAN]; /* station metric */ #endif /* ICOM */ @@ -328,6 +352,8 @@ struct chuunit { int burdist; /* burst distance */ int syndist; /* sync distance */ int burstcnt; /* format A bursts this minute */ + double maxsignal; /* signal level (modem only) */ + int gain; /* codec gain (modem only) */ /* * Format particulars @@ -344,7 +370,6 @@ struct chuunit { int fd_audio; /* audio port file descriptor */ double comp[SIZE]; /* decompanding table */ int port; /* codec port */ - int gain; /* codec gain */ int mongain; /* codec monitor gain */ int clipcnt; /* sample clip count */ int seccnt; /* second interval counter */ @@ -357,15 +382,15 @@ struct chuunit { double disc[LAG]; /* discriminator shift register */ double lpf[27]; /* FIR lowpass filter */ double monitor; /* audio monitor */ - double maxsignal; /* signal level */ int discptr; /* discriminator pointer */ /* - * Maximum likelihood UART variables + * Maximum-likelihood UART variables */ double baud; /* baud interval */ struct surv surv[8]; /* UART survivor structures */ int decptr; /* decode pointer */ + int decpha; /* decode phase */ int dbrk; /* holdoff counter */ #endif /* HAVE_AUDIO */ }; @@ -373,31 +398,32 @@ struct chuunit { /* * Function prototypes */ -static int chu_start P((int, struct peer *)); -static void chu_shutdown P((int, struct peer *)); -static void chu_receive P((struct recvbuf *)); -static void chu_poll P((int, struct peer *)); +static int chu_start (int, struct peer *); +static void chu_shutdown (int, struct peer *); +static void chu_receive (struct recvbuf *); +static void chu_second (int, struct peer *); +static void chu_poll (int, struct peer *); /* * More function prototypes */ -static void chu_decode P((struct peer *, int)); -static void chu_burst P((struct peer *)); -static void chu_clear P((struct peer *)); -static void chu_a P((struct peer *, int)); -static void chu_b P((struct peer *, int)); -static int chu_dist P((int, int)); -static double chu_major P((struct peer *)); +static void chu_decode (struct peer *, int, l_fp); +static void chu_burst (struct peer *); +static void chu_clear (struct peer *); +static void chu_a (struct peer *, int); +static void chu_b (struct peer *, int); +static int chu_dist (int, int); +static double chu_major (struct peer *); #ifdef HAVE_AUDIO -static void chu_uart P((struct surv *, double)); -static void chu_rf P((struct peer *, double)); -static void chu_gain P((struct peer *)); -static void chu_audio_receive P((struct recvbuf *rbufp)); +static void chu_uart (struct surv *, double); +static void chu_rf (struct peer *, double); +static void chu_gain (struct peer *); +static void chu_audio_receive (struct recvbuf *rbufp); #endif /* HAVE_AUDIO */ #ifdef ICOM -static int chu_newchan P((struct peer *, double)); +static int chu_newchan (struct peer *, double); #endif /* ICOM */ -static void chu_serial_receive P((struct recvbuf *rbufp)); +static void chu_serial_receive (struct recvbuf *rbufp); /* * Global variables @@ -410,7 +436,7 @@ static char hexchar[] = "0123456789abcdef_*="; * transmits on USB with carrier so we can use AM and the narrow SSB * filter. */ -static double qsy[NCHAN] = {3.330, 7.335, 14.670}; /* freq (MHz) */ +static double qsy[NCHAN] = {3.330, 7.850, 14.670}; /* freq (MHz) */ #endif /* ICOM */ /* @@ -423,7 +449,7 @@ struct refclock refclock_chu = { noentry, /* not used (old chu_control) */ noentry, /* initialize driver (not used) */ noentry, /* not used (old chu_buginfo) */ - NOFLAGS /* not used */ + chu_second /* housekeeping timer */ }; @@ -449,7 +475,7 @@ chu_start( double step; /* codec adjustment */ /* - * Open audio device. + * Open audio device. Don't complain if not there. */ fd_audio = audio_init(DEVICE_AUDIO, AUDIO_BUFSIZ, unit); #ifdef DEBUG @@ -458,12 +484,12 @@ chu_start( #endif /* - * Open serial port in raw mode. + * If audio is unavailable, Open serial port in raw mode. */ if (fd_audio > 0) { fd = fd_audio; } else { - sprintf(device, DEVICE, unit); + snprintf(device, sizeof(device), DEVICE, unit); fd = refclock_open(device, SPEED232, LDISC_RAW); } #else /* HAVE_AUDIO */ @@ -471,7 +497,7 @@ chu_start( /* * Open serial port in raw mode. */ - sprintf(device, DEVICE, unit); + snprintf(device, sizeof(device), DEVICE, unit); fd = refclock_open(device, SPEED232, LDISC_RAW); #endif /* HAVE_AUDIO */ if (fd <= 0) @@ -480,12 +506,8 @@ chu_start( /* * Allocate and initialize unit structure */ - if (!(up = (struct chuunit *) - emalloc(sizeof(struct chuunit)))) { - close(fd); - return (0); - } - memset((char *)up, 0, sizeof(struct chuunit)); + up = emalloc(sizeof(*up)); + memset(up, 0, sizeof(*up)); pp = peer->procptr; pp->unitptr = (caddr_t)up; pp->io.clock_recv = chu_receive; @@ -494,7 +516,9 @@ chu_start( pp->io.fd = fd; if (!io_addclock(&pp->io)) { close(fd); + pp->io.fd = -1; free(up); + pp->unitptr = NULL; return (0); } @@ -504,7 +528,7 @@ chu_start( peer->precision = PRECISION; pp->clockdesc = DESCRIPTION; strcpy(up->ident, "CHU"); - memcpy(&peer->refid, up->ident, 4); + memcpy(&pp->refid, up->ident, 4); DTOLFP(CHAR, &up->charstamp); #ifdef HAVE_AUDIO @@ -543,16 +567,11 @@ chu_start( } if (up->fd_icom > 0) { if (chu_newchan(peer, 0) != 0) { - NLOG(NLOG_SYNCEVENT | NLOG_SYSEVENT) - msyslog(LOG_NOTICE, - "icom: radio not found"); - up->errflg = CEVNT_FAULT; + msyslog(LOG_NOTICE, "icom: radio not found"); close(up->fd_icom); up->fd_icom = 0; } else { - NLOG(NLOG_SYNCEVENT | NLOG_SYSEVENT) - msyslog(LOG_NOTICE, - "icom: autotune enabled"); + msyslog(LOG_NOTICE, "icom: autotune enabled"); } } #endif /* ICOM */ @@ -674,7 +693,6 @@ chu_audio_receive( */ up->seccnt = (up->seccnt + 1) % SECOND; if (up->seccnt == 0) { - pp->second = (pp->second + 1) % 60; chu_gain(peer); } } @@ -698,7 +716,7 @@ chu_audio_receive( * * This routine implements a 300-baud Bell 103 modem with mark 2225 Hz * and space 2025 Hz. It uses a bandpass filter followed by a soft - * limiter, FM discriminator and lowpass filter. A maximum likelihood + * limiter, FM discriminator and lowpass filter. A maximum-likelihood * decoder samples the baseband signal at eight times the baud rate and * detects the start bit of each character. * @@ -723,7 +741,6 @@ chu_rf( double limit; /* limiter signal */ double disc; /* discriminator signal */ double lpf; /* lowpass signal */ - double span; /* UART signal span */ double dist; /* UART signal distance */ int i, j; @@ -732,7 +749,8 @@ chu_rf( /* * Bandpass filter. 4th-order elliptic, 500-Hz bandpass centered - * at 2125 Hz. Passband ripple 0.3 dB, stopband ripple 50 dB. + * at 2125 Hz. Passband ripple 0.3 dB, stopband ripple 50 dB, + * phase delay 0.24 ms. */ signal = (up->bpf[8] = up->bpf[7]) * 5.844676e-01; signal += (up->bpf[7] = up->bpf[6]) * 4.884860e-01; @@ -778,7 +796,7 @@ chu_rf( disc = -SQRT(-disc); /* - * Lowpass filter. Raised cosine, Ts = 1 / 300, beta = 0.1. + * Lowpass filter. Raised cosine FIR, Ts = 1 / 300, beta = 0.1. */ lpf = (up->lpf[26] = up->lpf[25]) * 2.538771e-02; lpf += (up->lpf[25] = up->lpf[24]) * 1.084671e-01; @@ -809,44 +827,68 @@ chu_rf( lpf += up->lpf[0] = disc * 2.538771e-02; /* - * Maximum likelihood decoder. The UART updates each of the + * Maximum-likelihood decoder. The UART updates each of the * eight survivors and determines the span, slice level and * tentative decoded character. Valid 11-bit characters are - * framed so that bit 1 and bit 11 (stop bits) are mark and bit - * 2 (start bit) is space. When a valid character is found, the + * framed so that bit 10 and bit 11 (stop bits) are mark and bit + * 1 (start bit) is space. When a valid character is found, the * survivor with maximum distance determines the final decoded * character. */ up->baud += 1. / SECOND; if (up->baud > 1. / (BAUD * 8.)) { up->baud -= 1. / (BAUD * 8.); + up->decptr = (up->decptr + 1) % 8; sp = &up->surv[up->decptr]; - span = sp->es_max - sp->es_min; - up->maxsignal += (span - up->maxsignal) / 80.; + sp->cstamp = up->timestamp; + chu_uart(sp, -lpf * AGAIN); if (up->dbrk > 0) { up->dbrk--; - } else if ((sp->uart & 0x403) == 0x401 && span > 1000.) - { - dist = 0; - j = 0; - for (i = 0; i < 8; i++) { - if (up->surv[i].dist > dist) { - dist = up->surv[i].dist; - j = i; - } + if (up->dbrk > 0) + return; + + up->decpha = up->decptr; + } + if (up->decptr != up->decpha) + return; + + dist = 0; + j = -1; + for (i = 0; i < 8; i++) { + + /* + * The timestamp is taken at the last bit, so + * for correct decoding we reqire sufficient + * span and correct start bit and two stop bits. + */ + if ((up->surv[i].uart & 0x601) != 0x600 || + up->surv[i].span < SPAN) + continue; + + if (up->surv[i].dist > dist) { + dist = up->surv[i].dist; + j = i; } - chu_decode(peer, (up->surv[j].uart >> 2) & - 0xff); - up->dbrk = 80; } - up->decptr = (up->decptr + 1) % 8; - chu_uart(sp, -lpf * AGAIN); + if (j < 0) + return; + + /* + * Process the character, then blank the decoder until + * the end of the next character.This sets the decoding + * phase of the entire burst from the phase of the first + * character. + */ + up->maxsignal = up->surv[j].span; + chu_decode(peer, (up->surv[j].uart >> 1) & 0xff, + up->surv[j].cstamp); + up->dbrk = 88; } } /* - * chu_uart - maximum likelihood UART + * chu_uart - maximum-likelihood UART * * This routine updates a shift register holding the last 11 envelope * samples. It then computes the slice level and span over these samples @@ -882,12 +924,15 @@ chu_uart( } /* - * Determine the slice level midway beteen the maximum and - * minimum and the span as the maximum less the minimum. Compute - * the distance on the assumption the first and last bits must - * be mark, the second space and the rest either mark or space. + * Determine the span as the maximum less the minimum and the + * slice level as the minimum plus a fraction of the span. Note + * the slight bias toward mark to correct for the modem tendency + * to make more mark than space errors. Compute the distance on + * the assumption the last two bits must be mark, the first + * space and the rest either mark or space. */ - slice = (es_max + es_min) / 2.; + sp->span = es_max - es_min; + slice = es_min + .45 * sp->span; dist = 0; sp->uart = 0; for (i = 1; i < 12; i++) { @@ -895,9 +940,9 @@ chu_uart( dtemp = sp->shift[i]; if (dtemp > slice) sp->uart |= 0x1; - if (i == 1 || i == 11) { + if (i == 1 || i == 2) { dist += dtemp - es_min; - } else if (i == 10) { + } else if (i == 11) { dist += es_max - dtemp; } else { if (dtemp > slice) @@ -906,9 +951,7 @@ chu_uart( dist += es_max - dtemp; } } - sp->es_max = es_max; - sp->es_min = es_min; - sp->dist = dist / (11 * (es_max - es_min)); + sp->dist = dist / (11 * sp->span); } #endif /* HAVE_AUDIO */ @@ -931,12 +974,8 @@ chu_serial_receive( pp = peer->procptr; up = (struct chuunit *)pp->unitptr; - /* - * Initialize pointers and read the timecode and timestamp. - */ - up->timestamp = rbufp->recv_time; dpt = (u_char *)&rbufp->recv_space; - chu_decode(peer, *dpt); + chu_decode(peer, *dpt, rbufp->recv_time); } @@ -946,7 +985,8 @@ chu_serial_receive( static void chu_decode( struct peer *peer, /* peer structure pointer */ - int hexhex /* data character */ + int hexhex, /* data character */ + l_fp cstamp /* data character timestamp */ ) { struct refclockproc *pp; @@ -979,11 +1019,11 @@ chu_decode( /* * Append the character to the current burst and append the - * timestamp to the timestamp list. + * character timestamp to the timestamp list. */ if (up->ndx < BURST) { up->cbuf[up->ndx] = hexhex & 0xff; - up->cstamp[up->ndx] = up->timestamp; + up->cstamp[up->ndx] = cstamp; up->ndx++; } @@ -1061,7 +1101,9 @@ chu_b( u_char code[11]; /* decoded timecode */ char tbuf[80]; /* trace buffer */ - l_fp offset; /* timestamp offset */ + char * p; + size_t chars; + size_t cb; int i; pp = peer->procptr; @@ -1069,15 +1111,25 @@ chu_b( /* * In a format B burst, a character is considered valid only if - * the first occurrence matches the last occurrence. The burst - * is considered valid only if all characters are valid; that - * is, only if the distance is 40. Note that once a valid frame - * has been found errors are ignored. + * the first occurence matches the last occurence. The burst is + * considered valid only if all characters are valid; that is, + * only if the distance is 40. Note that once a valid frame has + * been found errors are ignored. */ - sprintf(tbuf, "chuB %04x %2d %2d ", up->status, nchar, - -up->burdist); - for (i = 0; i < nchar; i++) - sprintf(&tbuf[strlen(tbuf)], "%02x", up->cbuf[i]); + snprintf(tbuf, sizeof(tbuf), "chuB %04x %4.0f %2d %2d ", + up->status, up->maxsignal, nchar, -up->burdist); + cb = sizeof(tbuf); + p = tbuf; + for (i = 0; i < nchar; i++) { + chars = strlen(p); + if (cb < chars + 1) { + msyslog(LOG_ERR, "chu_b() fatal out buffer"); + exit(1); + } + cb -= chars; + p += chars; + snprintf(p, cb, "%02x", up->cbuf[i]); + } if (pp->sloppyclockflag & CLK_FLAG4) record_clock_stats(&peer->srcadr, tbuf); #ifdef DEBUG @@ -1088,11 +1140,10 @@ chu_b( up->status |= BFRAME; return; } - up->status |= BVALID; /* - * Convert the burst data to internal format. If this succeeds, - * save the timestamps for later. + * Convert the burst data to internal format. Don't bother with + * the timestamps. */ for (i = 0; i < 5; i++) { code[2 * i] = hexchar[up->cbuf[i] & 0xf]; @@ -1104,17 +1155,9 @@ chu_b( up->status |= BFORMAT; return; } + up->status |= BVALID; if (up->leap & 0x8) up->dut = -up->dut; - offset.l_ui = 31; - offset.l_f = 0; - for (i = 0; i < nchar && i < 10; i++) { - up->tstamp[up->ntstamp] = up->cstamp[i]; - L_SUB(&up->tstamp[up->ntstamp], &offset); - L_ADD(&offset, &up->charstamp); - if (up->ntstamp < MAXSTAGE - 1) - up->ntstamp++; - } } @@ -1131,6 +1174,9 @@ chu_a( struct chuunit *up; char tbuf[80]; /* trace buffer */ + char * p; + size_t chars; + size_t cb; l_fp offset; /* timestamp offset */ int val; /* distance */ int temp; @@ -1143,7 +1189,7 @@ chu_a( * Determine correct burst phase. There are three cases * corresponding to in-phase, one character early or one * character late. These cases are distinguished by the position - * of the framing digits x6 at positions 0 and 5 and x3 at + * of the framing digits 0x6 at positions 0 and 5 and 0x3 at * positions 4 and 9. The correct phase is when the distance * relative to the framing digits is maximum. The burst is valid * only if the maximum distance is at least MINSYNC. @@ -1164,27 +1210,31 @@ chu_a( k = i; } } + + /* + * Extract the second number; it must be in the range 2 through + * 9 and the two repititions must be the same. + */ temp = (up->cbuf[k + 4] >> 4) & 0xf; - if (temp > 9 || k + 9 >= nchar || temp != ((up->cbuf[k + 9] >> - 4) & 0xf)) + if (temp < 2 || temp > 9 || k + 9 >= nchar || temp != + ((up->cbuf[k + 9] >> 4) & 0xf)) temp = 0; -#ifdef HAVE_AUDIO - if (up->fd_audio) - sprintf(tbuf, "chuA %04x %4.0f %2d %2d %2d %2d %1d ", - up->status, up->maxsignal, nchar, up->burdist, k, - up->syndist, temp); - else - sprintf(tbuf, "chuA %04x %2d %2d %2d %2d %1d ", - up->status, nchar, up->burdist, k, up->syndist, - temp); - -#else - sprintf(tbuf, "chuA %04x %2d %2d %2d %2d %1d ", up->status, - nchar, up->burdist, k, up->syndist, temp); -#endif /* HAVE_AUDIO */ - for (i = 0; i < nchar; i++) - sprintf(&tbuf[strlen(tbuf)], "%02x", - up->cbuf[i]); + snprintf(tbuf, sizeof(tbuf), + "chuA %04x %4.0f %2d %2d %2d %2d %1d ", up->status, + up->maxsignal, nchar, up->burdist, k, up->syndist, + temp); + cb = sizeof(tbuf); + p = tbuf; + for (i = 0; i < nchar; i++) { + chars = strlen(p); + if (cb < chars + 1) { + msyslog(LOG_ERR, "chu_a() fatal out buffer"); + exit(1); + } + cb -= chars; + p += chars; + snprintf(p, cb, "%02x", up->cbuf[i]); + } if (pp->sloppyclockflag & CLK_FLAG4) record_clock_stats(&peer->srcadr, tbuf); #ifdef DEBUG @@ -1203,8 +1253,11 @@ chu_a( * processing. In addition, the seconds decode is advanced from * the previous burst to the current one. */ - if (temp != 0) { - pp->second = 30 + temp; + if (temp == 0) { + up->status |= AFORMAT; + } else { + up->status |= AVALID; + up->second = pp->second = 30 + temp; offset.l_ui = 30 + temp; offset.l_f = 0; i = 0; @@ -1216,7 +1269,7 @@ chu_a( up->tstamp[up->ntstamp] = up->cstamp[i]; L_SUB(&up->tstamp[up->ntstamp], &offset); L_ADD(&offset, &up->charstamp); - if (up->ntstamp < MAXSTAGE - 1) + if (up->ntstamp < MAXSTAGE - 1) up->ntstamp++; } while (temp > up->prevsec) { @@ -1229,6 +1282,10 @@ chu_a( up->prevsec++; } } + + /* + * Stash the data in the decoding matrix. + */ i = -(2 * k); for (j = 0; j < nchar; j++) { if (i < 0 || i > 18) { @@ -1240,7 +1297,6 @@ chu_a( up->decode[i][(up->cbuf[j] >> 4) & 0xf]++; i++; } - up->status |= AVALID; up->burstcnt++; } @@ -1255,6 +1311,22 @@ chu_poll( ) { struct refclockproc *pp; + + pp = peer->procptr; + pp->polls++; +} + + +/* + * chu_second - process minute data + */ +static void +chu_second( + int unit, + struct peer *peer /* peer structure pointer */ + ) +{ + struct refclockproc *pp; struct chuunit *up; l_fp offset; char synchar, qual, leapchar; @@ -1263,40 +1335,24 @@ chu_poll( pp = peer->procptr; up = (struct chuunit *)pp->unitptr; - if (pp->coderecv == pp->codeproc) - up->errflg = CEVNT_TIMEOUT; - else - pp->polls++; /* - * If once in sync and the radio has not been heard for awhile - * (30 m), it is no longer reachable. If not heard in a long - * while (one day), turn out the lights and start from scratch. + * This routine is called once per minute to process the + * accumulated burst data. We do a bit of fancy footwork so that + * this doesn't run while burst data are being accumulated. */ - minset = ((current_time - peer->update) + 30) / 60; - if (up->status & INSYNC) { - if (minset > PANIC) - up->status = 0; - else if (minset <= HOLD) - peer->reach |= 1; - } + up->second = (up->second + 1) % 60; + if (up->second != 0) + return; /* * Process the last burst, if still in the burst buffer. - * Don't mess with anything if nothing has been heard. If the - * minute contains a valid A frame and valid B frame, assume - * synchronized; however, believe the time only if within metric - * threshold. Note the quality indicator is only for - * diagnostics; the data are used only if in sync and above - * metric threshold. + * If the minute contains a valid B frame with sufficient A + * frame metric, it is considered valid. However, the timecode + * is sent to clockstats even if invalid. */ chu_burst(peer); - if (up->burstcnt == 0) { -#ifdef ICOM - chu_newchan(peer, 0); -#endif /* ICOM */ - return; - } + minset = ((current_time - peer->update) + 30) / 60; dtemp = chu_major(peer); qual = 0; if (up->status & (BFRAME | AFRAME)) @@ -1307,7 +1363,7 @@ chu_poll( qual |= DECERR; if (up->status & STAMP) qual |= TSPERR; - if (up->status & AVALID && up->status & BVALID) + if (up->status & BVALID && dtemp >= MINMETRIC) up->status |= INSYNC; synchar = leapchar = ' '; if (!(up->status & INSYNC)) { @@ -1322,35 +1378,20 @@ chu_poll( } else { pp->leap = LEAP_NOWARNING; } -#ifdef HAVE_AUDIO - if (up->fd_audio) - sprintf(pp->a_lastcode, - "%c%1X %04d %3d %02d:%02d:%02d %c%x %+d %d %d %s %.0f %d", - synchar, qual, pp->year, pp->day, pp->hour, - pp->minute, pp->second, leapchar, up->dst, up->dut, - minset, up->gain, up->ident, dtemp, up->ntstamp); - else - sprintf(pp->a_lastcode, - "%c%1X %04d %3d %02d:%02d:%02d %c%x %+d %d %s %.0f %d", - synchar, qual, pp->year, pp->day, pp->hour, - pp->minute, pp->second, leapchar, up->dst, up->dut, - minset, up->ident, dtemp, up->ntstamp); -#else - sprintf(pp->a_lastcode, - "%c%1X %04d %3d %02d:%02d:%02d %c%x %+d %d %s %.0f %d", + snprintf(pp->a_lastcode, sizeof(pp->a_lastcode), + "%c%1X %04d %03d %02d:%02d:%02d %c%x %+d %d %d %s %.0f %d", synchar, qual, pp->year, pp->day, pp->hour, pp->minute, - pp->second, leapchar, up->dst, up->dut, minset, up->ident, - dtemp, up->ntstamp); -#endif /* HAVE_AUDIO */ + pp->second, leapchar, up->dst, up->dut, minset, up->gain, + up->ident, dtemp, up->ntstamp); pp->lencode = strlen(pp->a_lastcode); /* * If in sync and the signal metric is above threshold, the * timecode is ipso fatso valid and can be selected to - * discipline the clock. Be sure not to leave stray timestamps - * around if signals are too weak or the clock time is invalid. + * discipline the clock. */ - if (up->status & INSYNC && dtemp > METRIC) { + if (up->status & INSYNC && !(up->status & (DECODE | STAMP)) && + dtemp > MINMETRIC) { if (!clocktime(pp->day, pp->hour, pp->minute, 0, GMT, up->tstamp[0].l_ui, &pp->yearstart, &offset.l_ui)) { up->errflg = CEVNT_BADTIME; @@ -1358,15 +1399,14 @@ chu_poll( offset.l_uf = 0; for (i = 0; i < up->ntstamp; i++) refclock_process_offset(pp, offset, - up->tstamp[i], FUDGE + + up->tstamp[i], PDELAY + pp->fudgetime1); pp->lastref = up->timestamp; refclock_receive(peer); } - record_clock_stats(&peer->srcadr, pp->a_lastcode); - } else if (pp->sloppyclockflag & CLK_FLAG4) { - record_clock_stats(&peer->srcadr, pp->a_lastcode); } + if (dtemp > 0) + record_clock_stats(&peer->srcadr, pp->a_lastcode); #ifdef DEBUG if (debug) printf("chu: timecode %d %s\n", pp->lencode, @@ -1394,8 +1434,8 @@ chu_major( struct chuunit *up; u_char code[11]; /* decoded timecode */ - int mindist; /* minimum distance */ - int val1, val2; /* maximum distance */ + int metric; /* distance metric */ + int val1; /* maximum distance */ int synchar; /* stray cat */ int temp; int i, j, k; @@ -1406,54 +1446,32 @@ chu_major( /* * Majority decoder. Each burst encodes two replications at each * digit position in the timecode. Each row of the decoding - * matrix encodes the number of occurrences of each digit found + * matrix encodes the number of occurences of each digit found * at the corresponding position. The maximum over all * occurrences at each position is the distance for this - * position and the corresponding digit is the maximum - * likelihood candidate. If the distance is zero, assume a miss - * '_'; if the distance is not more than half the total number - * of occurrences, assume a soft error '*'; if two different - * digits with the same distance are found, assume a hard error - * '='. These will later cause a format error when the timecode - * is interpreted. The decoding distance is defined as the - * minimum distance over the first nine digits. The tenth digit - * varies over the seconds, so we don't count it. + * position and the corresponding digit is the maximum- + * likelihood candidate. If the distance is not more than half + * the total number of occurences, a majority has not been found + * and the data are discarded. The decoding distance is defined + * as the sum of the distances over the first nine digits. The + * tenth digit varies over the seconds, so we don't count it. */ - mindist = 16; + metric = 0; for (i = 0; i < 9; i++) { - val1 = val2 = 0; + val1 = 0; k = 0; for (j = 0; j < 16; j++) { temp = up->decode[i][j] + up->decode[i + 10][j]; if (temp > val1) { - val2 = val1; val1 = temp; k = j; } } - if (val1 == 0) - code[i] = HEX_MISS; - else if (val1 == val2) - code[i] = HEX_HARD; - else if (val1 <= up->burstcnt) - code[i] = HEX_SOFT; - else - code[i] = k; - if (val1 < mindist) - mindist = val1; - code[i] = hexchar[code[i]]; + if (val1 <= up->burstcnt) + up->status |= DECODE; + metric += val1; + code[i] = hexchar[k]; } - code[i] = 0; - - /* - * A valid timecode requires a minimum distance at least half - * the total number of occurrences. A valid timecode also - * requires at least 20 valid timestamps. - */ - if (up->burstcnt < MINBURST || mindist < up->burstcnt) - up->status |= DECODE; - if (up->ntstamp < MINSTAMP) - up->status |= STAMP; /* * Compute the timecode timestamp from the days, hours and @@ -1463,15 +1481,11 @@ chu_major( * for the years and does not use the years of the timecode. */ if (sscanf((char *)code, "%1x%3d%2d%2d", &synchar, &pp->day, - &pp->hour, &pp->minute) != 4) { - up->status |= AFORMAT; - return (0); - } - if (up->status & (DECODE | STAMP)) { - up->errflg = CEVNT_BADREPLY; - return (0); - } - return (mindist * 100. / (2. * up->burstcnt)); + &pp->hour, &pp->minute) != 4) + up->status |= DECODE; + if (up->ntstamp < MINSTAMP) + up->status |= STAMP; + return (metric); } @@ -1495,7 +1509,7 @@ chu_clear( */ up->ndx = up->prevsec = 0; up->burstcnt = up->ntstamp = 0; - up->status &= INSYNC; + up->status &= INSYNC | METRIC; for (i = 0; i < 20; i++) { for (j = 0; j < 16; j++) up->decode[i][j] = 0; @@ -1516,99 +1530,77 @@ chu_newchan( struct chuunit *up; struct refclockproc *pp; struct xmtr *sp; - char tbuf[80]; /* trace buffer */ int rval; double metric; - int i, j; + int i; pp = peer->procptr; up = (struct chuunit *)pp->unitptr; /* * The radio can be tuned to three channels: 0 (3330 kHz), 1 - * (7335 kHz) and 2 (14670 kHz). There are five one-minute + * (7850 kHz) and 2 (14670 kHz). There are five one-minute * dwells in each cycle. During the first dwell the radio is - * tuned to one of three probe channels; during the remaining - * four dwells the radio is tuned to the data channel. The probe - * channel is selects as the least recently used. At the end of - * each dwell the channel metrics are measured and the highest - * one is selected as the data channel. + * tuned to one of the three channels to measure the channel + * metric. The channel is selected as the one least recently + * measured. During the remaining four dwells the radio is tuned + * to the channel with the highest channel metric. */ if (up->fd_icom <= 0) return (0); - sp = &up->xmtr[up->achan]; + /* + * Update the current channel metric and age of all channels. + * Scan all channels for the highest metric. + */ + sp = &up->xmtr[up->chan]; sp->metric -= sp->integ[sp->iptr]; sp->integ[sp->iptr] = met; sp->metric += sp->integ[sp->iptr]; + sp->probe = 0; sp->iptr = (sp->iptr + 1) % ISTAGE; metric = 0; - j = 0; for (i = 0; i < NCHAN; i++) { up->xmtr[i].probe++; - if (i == up->achan) - up->xmtr[i].probe = 0; - if (up->xmtr[i].metric < metric) - continue; - metric = up->xmtr[i].metric; - j = i; - } - if (j != up->chan && metric > 0) { - up->chan = j; - sprintf(tbuf, "chu: QSY to %.3f MHz metric %.0f", - qsy[up->chan], metric); - if (pp->sloppyclockflag & CLK_FLAG4) - record_clock_stats(&peer->srcadr, tbuf); -#ifdef DEBUG - if (debug) - printf("%s\n", tbuf); -#endif + if (up->xmtr[i].metric > metric) { + up->status |= METRIC; + metric = up->xmtr[i].metric; + up->chan = i; + } } /* - * Start the next dwell. We speed up the initial sync a little. - * If not in sync and no bursts were heard the previous dwell, - * restart the probe. + * Start the next dwell. If the first dwell or no stations have + * been heard, continue round-robin scan. */ - rval = 0; - if (up->burstcnt == 0 && !(up->status & INSYNC)) - up->dwell = 0; -#ifdef DEBUG - if (debug) - printf( - "chu: at %ld dwell %d achan %d metric %.0f chan %d\n", - current_time, up->dwell, up->achan, sp->metric, - up->chan); -#endif - if (up->dwell == 0) { + up->dwell = (up->dwell + 1) % DWELL; + if (up->dwell == 0 || metric == 0) { rval = 0; for (i = 0; i < NCHAN; i++) { - if (up->xmtr[i].probe < rval) - continue; - rval = up->xmtr[i].probe; - up->achan = i; - } - rval = icom_freq(up->fd_icom, peer->ttl & 0x7f, - qsy[up->achan] + TUNE); -#ifdef DEBUG - if (debug) - printf("chu: at %ld probe channel %d\n", - current_time, up->achan); -#endif - } else { - if (up->achan != up->chan) { - rval = icom_freq(up->fd_icom, peer->ttl & 0x7f, - qsy[up->chan] + TUNE); - up->achan = up->chan; + if (up->xmtr[i].probe > rval) { + rval = up->xmtr[i].probe; + up->chan = i; + } } } - sprintf(up->ident, "CHU%d", up->achan); - memcpy(&peer->refid, up->ident, 4); - up->dwell = (up->dwell + 1) % DWELL; + + /* Retune the radio at each dwell in case somebody nudges the + * tuning knob. + */ + rval = icom_freq(up->fd_icom, peer->ttl & 0x7f, qsy[up->chan] + + TUNE); + snprintf(up->ident, sizeof(up->ident), "CHU%d", up->chan); + memcpy(&pp->refid, up->ident, 4); + memcpy(&peer->refid, up->ident, 4); + if (metric == 0 && up->status & METRIC) { + up->status &= ~METRIC; + refclock_report(peer, CEVNT_PROP); + } return (rval); } #endif /* ICOM */ + /* * chu_dist - determine the distance of two octet arguments */ @@ -1645,11 +1637,12 @@ chu_dist( /* * chu_gain - adjust codec gain * - * This routine is called once each second. If the signal envelope - * amplitude is too low, the codec gain is bumped up by four units; if - * too high, it is bumped down. The decoder is relatively insensitive to - * amplitude, so this crudity works just fine. The input port is set and - * the error flag is cleared, mostly to be ornery. + * This routine is called at the end of each second. During the second + * the number of signal clips above the MAXAMP threshold (6000). If + * there are no clips, the gain is bumped up; if there are more than + * MAXCLP clips (100), it is bumped down. The decoder is relatively + * insensitive to amplitude, so this crudity works just peachy. The + * routine also jiggles the input port and selectively mutes the */ static void chu_gain( |