* debug level is greater than one.
*/
/*
- * Interface definitions
+ * General definitions. Note the DGAIN parameter might need to be
+ * changed to fit the audio response of the radio at 100 Hz. The
+ * WWV/WWVH data subcarrier is transmitted at 10 dB down from 100
+ * percent modulation, so DGAIN should be at least 10 and more if the
+ * radio response droops at 100 Hz.
*/
#define DEVICE_AUDIO "/dev/audio" /* audio device name */
#define AUDIO_BUFSIZ 320 /* audio buffer size (50 ms) */
#define DATSIZ (DATCYC * MS) /* data filter size */
#define SYNCYC 800 /* minute filter cycles */
#define SYNSIZ (SYNCYC * MS) /* minute filter size */
+#define TCKCYC 5 /* tick filter cycles */
+#define TCKSIZ (TCKCYC * MS) /* tick filter size */
#define NCHAN 5 /* number of radio channels */
#define DCHAN 3 /* default radio channel (15 Mhz) */
#define AUDIO_PHI 5e-6 /* dispersion growth factor */
+#define DGAIN 10. /* subcarrier gain */
#ifdef IRIG_SUCKS
#define WIGGLE 11 /* wiggle filter length */
#endif /* IRIG_SUCKS */
#define ASNR 20. /* QRZ minute sync SNR threshold (dB) */
#define QTHR 2000. /* QSY minute sync threshold */
#define QSNR 20. /* QSY minute sync SNR threshold (dB) */
-#define STHR 1000. /* second sync threshold */
-#define SSNR 20. /* second sync SNR threshold (dB) */
+#define STHR 2000. /* second sync threshold */
+#define SSNR 15. /* second sync SNR threshold (dB) */
#define SCMP 10 /* second sync compare threshold */
-#define DGAIN 10. /* subcarrier gain */
#define DTHR 1000. /* bit threshold */
#define DSNR 10. /* bit SNR threshold (dB) */
#define AMIN 3 /* min bit count */
static double qbuf[DATSIZ]; /* data Q channel delay line */
static int jptr; /* sync channel pointer */
+ static int kptr; /* tick channel pointer */
+
+ static int csinptr; /* wwv channel phase */
static double cibuf[SYNSIZ]; /* wwv I channel delay line */
static double cqbuf[SYNSIZ]; /* wwv Q channel delay line */
static double ciamp; /* wwv I channel amplitude */
static double cqamp; /* wwv Q channel amplitude */
- static int csinptr; /* wwv channel phase */
+
+ static double csibuf[TCKSIZ]; /* wwv I tick delay line */
+ static double csqbuf[TCKSIZ]; /* wwv Q tick delay line */
+ static double csiamp; /* wwv I tick amplitude */
+ static double csqamp; /* wwv Q tick amplitude */
+
+ static int hsinptr; /* wwvh channels phase */
static double hibuf[SYNSIZ]; /* wwvh I channel delay line */
static double hqbuf[SYNSIZ]; /* wwvh Q channel delay line */
static double hiamp; /* wwvh I channel amplitude */
static double hqamp; /* wwvh Q channel amplitude */
- static int hsinptr; /* wwvh channels phase */
+
+ static double hsibuf[TCKSIZ]; /* wwvh I tick delay line */
+ static double hsqbuf[TCKSIZ]; /* wwvh Q tick delay line */
+ static double hsiamp; /* wwvh I tick amplitude */
+ static double hsqamp; /* wwvh Q tick amplitude */
static double epobuf[SECOND]; /* epoch sync comb filter */
static double epomax; /* epoch sync amplitude buffer */
memset((char *)qbuf, 0, sizeof(qbuf));
memset((char *)cibuf, 0, sizeof(cibuf));
memset((char *)cqbuf, 0, sizeof(cqbuf));
+ memset((char *)csibuf, 0, sizeof(csibuf));
+ memset((char *)csqbuf, 0, sizeof(csqbuf));
memset((char *)hibuf, 0, sizeof(hibuf));
memset((char *)hqbuf, 0, sizeof(hqbuf));
+ memset((char *)hsibuf, 0, sizeof(hsibuf));
+ memset((char *)hsqbuf, 0, sizeof(hsqbuf));
memset((char *)epobuf, 0, sizeof(epobuf));
}
+ lpf[4] * 3.281435e-03;
/*
- * The I and Q quadrature data signals are produced by
+ * The 100-Hz data signal is demodulated using a pair of
+ * quadrature multipliers, matched filters and a phase lock
+ * loop. The I and Q quadrature data signals are produced by
* multiplying the filtered signal by 100-Hz sine and cosine
- * signals, respectively. The data signals are processed by
- * 170-ms synchronous matched filters to produce the amplitude
- * and phase signals used by the decoder. The signals are scaled
+ * signals, respectively. The signals are processed by 170-ms
+ * synchronous matched filters to produce the amplitude and
+ * phase signals used by the demodulator. The signals are scaled
* to produce unit energy at the maximum value.
*/
i = up->datapt;
up->datapt = (up->datapt + IN100) % 80;
- dtemp = sintab[i] * data / 4. / DATCYC;
+ dtemp = sintab[i] * data / (MS / 2. * DATCYC);
up->irig -= ibuf[iptr];
ibuf[iptr] = dtemp;
up->irig += dtemp;
i = (i + 20) % 80;
- dtemp = sintab[i] * data / 4. / DATCYC;
+ dtemp = sintab[i] * data / (MS / 2. * DATCYC);
up->qrig -= qbuf[iptr];
qbuf[iptr] = dtemp;
up->qrig += dtemp;
+ bpf[8] * 8.203628e-03;
/*
- * The I and Q quadrature minute sync signals are produced by
- * multiplying the filtered signal by 1000-Hz (WWV) and 1200-Hz
- * (WWVH) sine and cosine signals, respectively. The resulting
- * signals are processed by 800-ms synchronous matched filters
- * and combined to produce the minute sync signal and detect
- * which one (or both) the WWV or WWVH signal is present. The
- * signals are scaled to produce unit energy at the maximum
- * value.
+ * The 1000/1200 sync signals are demodulated using a pair of
+ * quadrature multipliers and matched filters. However,
+ * synchronous demodulation at these frequencies is impractical,
+ * so only the signal amplitude is used. The I and Q quadrature
+ * sync signals are produced by multiplying the filtered signal
+ * by 1000-Hz (WWV) and 1200-Hz (WWVH) sine and cosine signals,
+ * respectively. The WWV and WWVH signals are processed by 800-
+ * ms synchronous matched filters and combined to produce the
+ * minute sync signal and detect which one (or both) the WWV or
+ * WWVH signal is present. The WWV and WWVH signals are also
+ * processed by 5-ms synchronous matched filters and combined to
+ * produce the second sync signal. The signals are scaled to
+ * produce unit energy at the maximum value.
*
* Note the master timing ramps, which run continuously. The
* minute counter (mphase) counts the samples in the minute,
*/
i = csinptr;
csinptr = (csinptr + IN1000) % 80;
- dtemp = sintab[i] * syncx / 4.;
+
+ dtemp = sintab[i] * syncx / (MS / 2.);
ciamp -= cibuf[jptr];
cibuf[jptr] = dtemp;
ciamp += dtemp;
+ csiamp -= csibuf[kptr];
+ csibuf[kptr] = dtemp;
+ csiamp += dtemp;
i = (i + 20) % 80;
- dtemp = sintab[i] * syncx / 4.;
+ dtemp = sintab[i] * syncx / (MS / 2.);
cqamp -= cqbuf[jptr];
cqbuf[jptr] = dtemp;
cqamp += dtemp;
+ csqamp -= csqbuf[kptr];
+ csqbuf[kptr] = dtemp;
+ csqamp += dtemp;
sp = &up->mitig[up->achan].wwv;
sp->amp = sqrt(ciamp * ciamp + cqamp * cqamp) / SYNCYC;
*/
i = hsinptr;
hsinptr = (hsinptr + IN1200) % 80;
- dtemp = sintab[i] * syncx / 4.;
+
+ dtemp = sintab[i] * syncx / (MS / 2.);
hiamp -= hibuf[jptr];
hibuf[jptr] = dtemp;
hiamp += dtemp;
+ hsiamp -= hsibuf[kptr];
+ hsibuf[kptr] = dtemp;
+ hsiamp += dtemp;
i = (i + 20) % 80;
- dtemp = sintab[i] * syncx / 4.;
+ dtemp = sintab[i] * syncx / (MS / 2.);
hqamp -= hqbuf[jptr];
hqbuf[jptr] = dtemp;
hqamp += dtemp;
+ hsqamp -= hsqbuf[kptr];
+ hsqbuf[kptr] = dtemp;
+ hsqamp += dtemp;
rp = &up->mitig[up->achan].wwvh;
rp->amp = sqrt(hiamp * hiamp + hqamp * hqamp) / SYNCYC;
if (!(up->status & MSYNC))
wwv_qrz(peer, rp, (int)(pp->fudgetime2 * SECOND));
jptr = (jptr + 1) % SYNSIZ;
+ kptr = (kptr + 1) % TCKSIZ;
/*
* The following section is called once per minute. It does
*/
if (up->status & SELV) {
pdelay = (int)(pp->fudgetime1 * SECOND);
-
- /*
- * WWV FIR matched filter, five cycles of 1000-Hz
- * sinewave normalized for unit energy per cycle..
- */
- mf[40] = mf[39];
- mfsync = (mf[39] = mf[38]) * 1.767767e-01;
- mfsync += (mf[38] = mf[37]) * 2.500000e-01;
- mfsync += (mf[37] = mf[36]) * 1.767767e-01;
- mf[36] = mf[35];
- mfsync += (mf[35] = mf[34]) * -1.767767e-01;
- mfsync += (mf[34] = mf[33]) * -2.500000e-01;
- mfsync += (mf[33] = mf[32]) * -1.767767e-01;
- mf[32] = mf[31];
- mfsync += (mf[31] = mf[30]) * 1.767767e-01;
- mfsync += (mf[30] = mf[29]) * 2.500000e-01;
- mfsync += (mf[29] = mf[28]) * 1.767767e-01;
- mf[28] = mf[27];
- mfsync += (mf[27] = mf[26]) * -1.767767e-01;
- mfsync += (mf[26] = mf[25]) * -2.500000e-01;
- mfsync += (mf[25] = mf[24]) * -1.767767e-01;
- mf[24] = mf[23];
- mfsync += (mf[23] = mf[22]) * 1.767767e-01;
- mfsync += (mf[22] = mf[21]) * 2.500000e-01;
- mfsync += (mf[21] = mf[20]) * 1.767767e-01;
- mf[20] = mf[19];
- mfsync += (mf[19] = mf[18]) * -1.767767e-01;
- mfsync += (mf[18] = mf[17]) * -2.500000e-01;
- mfsync += (mf[17] = mf[16]) * -1.767767e-01;
- mf[16] = mf[15];
- mfsync += (mf[15] = mf[14]) * 1.767767e-01;
- mfsync += (mf[14] = mf[13]) * 2.500000e-01;
- mfsync += (mf[13] = mf[12]) * 1.767767e-01;
- mf[12] = mf[11];
- mfsync += (mf[11] = mf[10]) * -1.767767e-01;
- mfsync += (mf[10] = mf[9]) * -2.500000e-01;
- mfsync += (mf[9] = mf[8]) * -1.767767e-01;
- mf[8] = mf[7];
- mfsync += (mf[7] = mf[6]) * 1.767767e-01;
- mfsync += (mf[6] = mf[5]) * 2.500000e-01;
- mfsync += (mf[5] = mf[4]) * 1.767767e-01;
- mf[4] = mf[3];
- mfsync += (mf[3] = mf[2]) * -1.767767e-01;
- mfsync += (mf[2] = mf[1]) * -2.500000e-01;
- mfsync += (mf[1] = mf[0]) * -1.767767e-01;
- mf[0] = syncx;
+ mfsync = sqrt(csiamp * csiamp + csqamp * csqamp) /
+ TCKCYC;
} else if (up->status & SELH) {
pdelay = (int)(pp->fudgetime2 * SECOND);
-
- /*
- * WWVH FIR matched filter, six cycles of 1200-Hz
- * sinewave normalized for unit energy per cycle.
- */
- mf[40] = mf[39];
- mfsync = (mf[39] = mf[38]) * 2.022542e-01;
- mfsync += (mf[38] = mf[37]) * 2.377641e-01;
- mfsync += (mf[37] = mf[36]) * 7.725425e-02;
- mfsync += (mf[36] = mf[35]) * -1.469463e-01;
- mfsync += (mf[35] = mf[34]) * -2.500000e-01;
- mfsync += (mf[34] = mf[33]) * -1.469463e-01;
- mfsync += (mf[33] = mf[32]) * 7.725425e-02;
- mfsync += (mf[32] = mf[31]) * 2.377641e-01;
- mfsync += (mf[31] = mf[30]) * 2.022542e-01;
- mf[30] = mf[29];
- mfsync += (mf[29] = mf[28]) * -2.022542e-01;
- mfsync += (mf[28] = mf[27]) * -2.377641e-01;
- mfsync += (mf[27] = mf[26]) * -7.725425e-02;
- mfsync += (mf[26] = mf[25]) * 1.469463e-01;
- mfsync += (mf[25] = mf[24]) * 2.500000e-01;
- mfsync += (mf[24] = mf[23]) * 1.469463e-01;
- mfsync += (mf[23] = mf[22]) * -7.725425e-02;
- mfsync += (mf[22] = mf[21]) * -2.377641e-01;
- mfsync += (mf[21] = mf[20]) * -2.022542e-01;
- mf[20] = mf[19];
- mfsync += (mf[19] = mf[18]) * 2.022542e-01;
- mfsync += (mf[18] = mf[17]) * 2.377641e-01;
- mfsync += (mf[17] = mf[16]) * 7.725425e-02;
- mfsync += (mf[16] = mf[15]) * -1.469463e-01;
- mfsync += (mf[15] = mf[14]) * -2.500000e-01;
- mfsync += (mf[14] = mf[13]) * -1.469463e-01;
- mfsync += (mf[13] = mf[12]) * 7.725425e-02;
- mfsync += (mf[12] = mf[11]) * 2.377641e-01;
- mfsync += (mf[11] = mf[10]) * 2.022542e-01;
- mf[10] = mf[9];
- mfsync += (mf[9] = mf[8]) * -2.022542e-01;
- mfsync += (mf[8] = mf[7]) * -2.377641e-01;
- mfsync += (mf[7] = mf[6]) * -7.725425e-02;
- mfsync += (mf[6] = mf[5]) * 1.469463e-01;
- mfsync += (mf[5] = mf[4]) * 2.500000e-01;
- mfsync += (mf[4] = mf[3]) * 1.469463e-01;
- mfsync += (mf[3] = mf[2]) * -7.725425e-02;
- mfsync += (mf[2] = mf[1]) * -2.377641e-01;
- mfsync += (mf[1] = mf[0]) * -2.022542e-01;
- mf[0] = syncx;
+ mfsync = sqrt(hsiamp * hsiamp + hsqamp * hsqamp) /
+ TCKCYC;
} else {
- mfsync = 0;
pdelay = 0;
+ mfsync = 0;
}
/*
* computed from the maximum sample and the envelope of the
* sample 6 ms before it, so if we slip more than a cycle the
* SNR should plummet. The signal is scaled to produce unit
- * energy at the maximum value. The noise is measured as the
- * energy of the sixth cycle before the peak.
+ * energy at the maximum value.
*/
dtemp = (epobuf[epoch] += (mfsync - epobuf[epoch]) /
up->avgint);
if (epoch == 0) {
int k, j;
- up->epomax = epomax / 5.;
+ up->epomax = epomax;
dtemp = 0;
- k = epopos - 6 * MS;
+ k = epopos - 7 * MS;
for (j = 0; j < MS; j++) {
if (k < 0)
k += SECOND;
k++;
}
up->eposnr = wwv_snr(epomax, sqrt(dtemp / MS));
- epopos -= pdelay + 5 * MS;
+ epopos -= pdelay + TCKCYC * MS;
if (epopos < 0)
epopos += SECOND;
wwv_endpoc(peer, epopos);
/*
* If the signal amplitude or SNR fall below thresholds, dim the
- * second sync lamp and start over. If no stations are heard, go
- * no further.
+ * second sync lamp and start over. If no stations are heard we
+ * are either in a probe cycle or the ions are dim. In that case
+ * allow the amplitude and SNR to discharge and go no further.
*/
if (up->epomax < STHR || up->eposnr < SSNR) {
up->status &= ~(SSYNC | FGATE);
* epoches is determined. If the longest run is at least 10
* seconds, the SSYNC bit is lit and the value becomes the
* reference epoch for the next interval. If not, the second
- * synd lamp is dark and flashers set.
+ * sync lamp is dark and flashers set.
*/
if (maxrun > 0 && mepoch == xepoch) {
maxrun += syncnt;
* greater than 1 ms, the counter is decremented. If the epoch
* change is less than 0.5 ms, the counter is incremented. If
* the counter increments to +3, the averaging interval is
- * doubled and the counter set to zero; if it increments to -3,
+ * doubled and the counter set to zero; if it decrements to -3,
* the interval is halved and the counter set to zero.
*
* Here be spooks. From careful observations, the epoch
dtemp = (mepoch - zepoch) % SECOND;
if (up->status & FGATE) {
if (abs(dtemp) < MAXFREQ * MINAVG) {
- if (maxrun * abs(mepoch - zepoch) <
- avgcnt) {
+ if (maxrun * abs(dtemp) < avgcnt) {
up->freq += dtemp / avgcnt;
if (up->freq > MAXFREQ)
up->freq = MAXFREQ;
else if (up->freq < -MAXFREQ)
up->freq = -MAXFREQ;
}
- if (abs(dtemp) < MAXFREQ * MINAVG / 2) {
+ if (abs(dtemp) < MAXFREQ * MINAVG / 2.) {
if (avginc < 3) {
avginc++;
} else {
projects / thirdparty / ntp.git / commitdiff
