1 /* $NetBSD: tg.c,v 1.5 2020/05/25 20:47:37 christos Exp $ */
2
3 /*
4 * tg.c generate WWV or IRIG signals for test
5 */
6 /*
7 * This program can generate audio signals that simulate the WWV/H
8 * broadcast timecode. Alternatively, it can generate the IRIG-B
9 * timecode commonly used to synchronize laboratory equipment. It is
10 * intended to test the WWV/H driver (refclock_wwv.c) and the IRIG
11 * driver (refclock_irig.c) in the NTP driver collection.
12 *
13 * Besides testing the drivers themselves, this program can be used to
14 * synchronize remote machines over audio transmission lines or program
15 * feeds. The program reads the time on the local machine and sets the
16 * initial epoch of the signal generator within one millisecond.
17 * Alernatively, the initial epoch can be set to an arbitrary time. This
18 * is useful when searching for bugs and testing for correct response to
19 * a leap second in UTC. Note however, the ultimate accuracy is limited
20 * by the intrinsic frequency error of the codec sample clock, which can
21 # reach well over 100 PPM.
22 *
23 * The default is to route generated signals to the line output
24 * jack; the s option on the command line routes these signals to the
25 * internal speaker as well. The v option controls the speaker volume
26 * over the range 0-255. The signal generator by default uses WWV
27 * format; the h option switches to WWVH format and the i option
28 * switches to IRIG-B format.
29 *
30 * Once started the program runs continuously. The default initial epoch
31 * for the signal generator is read from the computer system clock when
32 * the program starts. The y option specifies an alternate epoch using a
33 * string yydddhhmmss, where yy is the year of century, ddd the day of
34 * year, hh the hour of day and mm the minute of hour. For instance,
35 * 1946Z on 1 January 2006 is 060011946. The l option lights the leap
36 * warning bit in the WWV/H timecode, so is handy to check for correct
37 * behavior at the next leap second epoch. The remaining options are
38 * specified below under the Parse Options heading. Most of these are
39 * for testing.
40 *
41 * During operation the program displays the WWV/H timecode (9 digits)
42 * or IRIG timecode (20 digits) as each new string is constructed. The
43 * display is followed by the BCD binary bits as transmitted. Note that
44 * the transmissionorder is low-order first as the frame is processed
45 * left to right. For WWV/H The leap warning L preceeds the first bit.
46 * For IRIG the on-time marker M preceeds the first (units) bit, so its
47 * code is delayed one bit and the next digit (tens) needs only three
48 * bits.
49 *
50 * The program has been tested with the Sun Blade 1500 running Solaris
51 * 10, but not yet with other machines. It uses no special features and
52 * should be readily portable to other hardware and operating systems.
53 */
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <time.h>
57 #include <sys/audio.h>
58 #include <math.h>
59 #include <errno.h>
60 #include <sys/types.h>
61 #include <sys/stat.h>
62 #include <fcntl.h>
63 #include <string.h>
64 #include <unistd.h>
65
66 #define SECOND 8000 /* one second of 125-us samples */
67 #define BUFLNG 400 /* buffer size */
68 #define DEVICE "/dev/audio" /* default audio device */
69 #define WWV 0 /* WWV encoder */
70 #define IRIG 1 /* IRIG-B encoder */
71 #define OFF 0 /* zero amplitude */
72 #define LOW 1 /* low amplitude */
73 #define HIGH 2 /* high amplitude */
74 #define DATA0 200 /* WWV/H 0 pulse */
75 #define DATA1 500 /* WWV/H 1 pulse */
76 #define PI 800 /* WWV/H PI pulse */
77 #define M2 2 /* IRIG 0 pulse */
78 #define M5 5 /* IRIG 1 pulse */
79 #define M8 8 /* IRIG PI pulse */
80
81 /*
82 * Companded sine table amplitude 3000 units
83 */
84 int c3000[] = {1, 48, 63, 70, 78, 82, 85, 89, 92, 94, /* 0-9 */
85 96, 98, 99, 100, 101, 101, 102, 103, 103, 103, /* 10-19 */
86 103, 103, 103, 103, 102, 101, 101, 100, 99, 98, /* 20-29 */
87 96, 94, 92, 89, 85, 82, 78, 70, 63, 48, /* 30-39 */
88 129, 176, 191, 198, 206, 210, 213, 217, 220, 222, /* 40-49 */
89 224, 226, 227, 228, 229, 229, 230, 231, 231, 231, /* 50-59 */
90 231, 231, 231, 231, 230, 229, 229, 228, 227, 226, /* 60-69 */
91 224, 222, 220, 217, 213, 210, 206, 198, 191, 176}; /* 70-79 */
92 /*
93 * Companded sine table amplitude 6000 units
94 */
95 int c6000[] = {1, 63, 78, 86, 93, 98, 101, 104, 107, 110, /* 0-9 */
96 112, 113, 115, 116, 117, 117, 118, 118, 119, 119, /* 10-19 */
97 119, 119, 119, 118, 118, 117, 117, 116, 115, 113, /* 20-29 */
98 112, 110, 107, 104, 101, 98, 93, 86, 78, 63, /* 30-39 */
99 129, 191, 206, 214, 221, 226, 229, 232, 235, 238, /* 40-49 */
100 240, 241, 243, 244, 245, 245, 246, 246, 247, 247, /* 50-59 */
101 247, 247, 247, 246, 246, 245, 245, 244, 243, 241, /* 60-69 */
102 240, 238, 235, 232, 229, 226, 221, 214, 206, 191}; /* 70-79 */
103
104 /*
105 * Decoder operations at the end of each second are driven by a state
106 * machine. The transition matrix consists of a dispatch table indexed
107 * by second number. Each entry in the table contains a case switch
108 * number and argument.
109 */
110 struct progx {
111 int sw; /* case switch number */
112 int arg; /* argument */
113 };
114
115 /*
116 * Case switch numbers
117 */
118 #define DATA 0 /* send data (0, 1, PI) */
119 #define COEF 1 /* send BCD bit */
120 #define DEC 2 /* decrement to next digit */
121 #define MIN 3 /* minute pulse */
122 #define LEAP 4 /* leap warning */
123 #define DUT1 5 /* DUT1 bits */
124 #define DST1 6 /* DST1 bit */
125 #define DST2 7 /* DST2 bit */
126
127 /*
128 * WWV/H format (100-Hz, 9 digits, 1 m frame)
129 */
130 struct progx progx[] = {
131 {MIN, 800}, /* 0 minute sync pulse */
132 {DATA, DATA0}, /* 1 */
133 {DST2, 0}, /* 2 DST2 */
134 {LEAP, 0}, /* 3 leap warning */
135 {COEF, 1}, /* 4 1 year units */
136 {COEF, 2}, /* 5 2 */
137 {COEF, 4}, /* 6 4 */
138 {COEF, 8}, /* 7 8 */
139 {DEC, DATA0}, /* 8 */
140 {DATA, PI}, /* 9 p1 */
141 {COEF, 1}, /* 10 1 minute units */
142 {COEF, 2}, /* 11 2 */
143 {COEF, 4}, /* 12 4 */
144 {COEF, 8}, /* 13 8 */
145 {DEC, DATA0}, /* 14 */
146 {COEF, 1}, /* 15 10 minute tens */
147 {COEF, 2}, /* 16 20 */
148 {COEF, 4}, /* 17 40 */
149 {COEF, 8}, /* 18 80 (not used) */
150 {DEC, PI}, /* 19 p2 */
151 {COEF, 1}, /* 20 1 hour units */
152 {COEF, 2}, /* 21 2 */
153 {COEF, 4}, /* 22 4 */
154 {COEF, 8}, /* 23 8 */
155 {DEC, DATA0}, /* 24 */
156 {COEF, 1}, /* 25 10 hour tens */
157 {COEF, 2}, /* 26 20 */
158 {COEF, 4}, /* 27 40 (not used) */
159 {COEF, 8}, /* 28 80 (not used) */
160 {DEC, PI}, /* 29 p3 */
161 {COEF, 1}, /* 30 1 day units */
162 {COEF, 2}, /* 31 2 */
163 {COEF, 4}, /* 32 4 */
164 {COEF, 8}, /* 33 8 */
165 {DEC, DATA0}, /* 34 not used */
166 {COEF, 1}, /* 35 10 day tens */
167 {COEF, 2}, /* 36 20 */
168 {COEF, 4}, /* 37 40 */
169 {COEF, 8}, /* 38 80 */
170 {DEC, PI}, /* 39 p4 */
171 {COEF, 1}, /* 40 100 day hundreds */
172 {COEF, 2}, /* 41 200 */
173 {COEF, 4}, /* 42 400 (not used) */
174 {COEF, 8}, /* 43 800 (not used) */
175 {DEC, DATA0}, /* 44 */
176 {DATA, DATA0}, /* 45 */
177 {DATA, DATA0}, /* 46 */
178 {DATA, DATA0}, /* 47 */
179 {DATA, DATA0}, /* 48 */
180 {DATA, PI}, /* 49 p5 */
181 {DUT1, 8}, /* 50 DUT1 sign */
182 {COEF, 1}, /* 51 10 year tens */
183 {COEF, 2}, /* 52 20 */
184 {COEF, 4}, /* 53 40 */
185 {COEF, 8}, /* 54 80 */
186 {DST1, 0}, /* 55 DST1 */
187 {DUT1, 1}, /* 56 0.1 DUT1 fraction */
188 {DUT1, 2}, /* 57 0.2 */
189 {DUT1, 4}, /* 58 0.4 */
190 {DATA, PI}, /* 59 p6 */
191 {DATA, DATA0}, /* 60 leap */
192 };
193
194 /*
195 * IRIG format except first frame (1000 Hz, 20 digits, 1 s frame)
196 */
197 struct progx progy[] = {
198 {COEF, 1}, /* 0 1 units */
199 {COEF, 2}, /* 1 2 */
200 {COEF, 4}, /* 2 4 */
201 {COEF, 8}, /* 3 8 */
202 {DEC, M2}, /* 4 im */
203 {COEF, 1}, /* 5 10 tens */
204 {COEF, 2}, /* 6 20 */
205 {COEF, 4}, /* 7 40 */
206 {COEF, 8}, /* 8 80 */
207 {DEC, M8}, /* 9 pi */
208 };
209
210 /*
211 * IRIG format first frame (1000 Hz, 20 digits, 1 s frame)
212 */
213 struct progx progz[] = {
214 {MIN, M8}, /* 0 pi (second) */
215 {COEF, 1}, /* 1 1 units */
216 {COEF, 2}, /* 2 2 */
217 {COEF, 4}, /* 3 4 */
218 {COEF, 8}, /* 4 8 */
219 {DEC, M2}, /* 5 im */
220 {COEF, 1}, /* 6 10 tens */
221 {COEF, 2}, /* 7 20 */
222 {COEF, 4}, /* 8 40 */
223 {DEC, M8}, /* 9 pi */
224 };
225
226 /*
227 * Forward declarations
228 */
229 void sec(int); /* send second */
230 void digit(int); /* encode digit */
231 void peep(int, int, int); /* send cycles */
232 void delay(int); /* delay samples */
233
234 /*
235 * Global variables
236 */
237 char buffer[BUFLNG]; /* output buffer */
238 int bufcnt = 0; /* buffer counter */
239 int second = 0; /* seconds counter */
240 int fd; /* audio codec file descriptor */
241 int tone = 1000; /* WWV sync frequency */
242 int level = AUDIO_MAX_GAIN / 8; /* output level */
243 int port = AUDIO_LINE_OUT; /* output port */
244 int encode = WWV; /* encoder select */
245 int leap = 0; /* leap indicator */
246 int dst = 0; /* winter/summer time */
247 int dut1 = 0; /* DUT1 correction (sign, magnitude) */
248 int utc = 0; /* option epoch */
249
250 /*
251 * Main program
252 */
253 int
main(int argc,char ** argv)254 main(
255 int argc, /* command line options */
256 char **argv /* poiniter to list of tokens */
257 )
258 {
259 struct timeval tv; /* system clock at startup */
260 audio_info_t info; /* Sun audio structure */
261 struct tm *tm = NULL; /* structure returned by gmtime */
262 char device[50]; /* audio device */
263 char code[100]; /* timecode */
264 int rval, temp, arg, sw, ptr;
265 int minute, hour, day, year;
266 int i;
267
268 /*
269 * Parse options
270 */
271 strlcpy(device, DEVICE, sizeof(device));
272 year = 0;
273 while ((temp = getopt(argc, argv, "a:dhilsu:v:y:")) != -1) {
274 switch (temp) {
275
276 case 'a': /* specify audio device (/dev/audio) */
277 strlcpy(device, optarg, sizeof(device));
278 break;
279
280 case 'd': /* set DST for summer (WWV/H only) */
281 dst++;
282 break;
283
284 case 'h': /* select WWVH sync frequency */
285 tone = 1200;
286 break;
287
288 case 'i': /* select irig format */
289 encode = IRIG;
290 break;
291
292 case 'l': /* set leap warning bit (WWV/H only) */
293 leap++;
294 break;
295
296 case 's': /* enable speaker */
297 port |= AUDIO_SPEAKER;
298 break;
299
300 case 'u': /* set DUT1 offset (-7 to +7) */
301 sscanf(optarg, "%d", &dut1);
302 if (dut1 < 0)
303 dut1 = abs(dut1);
304 else
305 dut1 |= 0x8;
306 break;
307
308 case 'v': /* set output level (0-255) */
309 sscanf(optarg, "%d", &level);
310 break;
311
312 case 'y': /* set initial date and time */
313 sscanf(optarg, "%2d%3d%2d%2d", &year, &day,
314 &hour, &minute);
315 utc++;
316 break;
317
318 defult:
319 printf("invalid option %c\n", temp);
320 break;
321 }
322 }
323
324 /*
325 * Open audio device and set options
326 */
327 fd = open("/dev/audio", O_WRONLY);
328 if (fd <= 0) {
329 printf("audio open %s\n", strerror(errno));
330 exit(1);
331 }
332 rval = ioctl(fd, AUDIO_GETINFO, &info);
333 if (rval < 0) {
334 printf("audio control %s\n", strerror(errno));
335 exit(0);
336 }
337 info.play.port = port;
338 info.play.gain = level;
339 info.play.sample_rate = SECOND;
340 info.play.channels = 1;
341 info.play.precision = 8;
342 info.play.encoding = AUDIO_ENCODING_ULAW;
343 printf("port %d gain %d rate %d chan %d prec %d encode %d\n",
344 info.play.port, info.play.gain, info.play.sample_rate,
345 info.play.channels, info.play.precision,
346 info.play.encoding);
347 ioctl(fd, AUDIO_SETINFO, &info);
348
349 /*
350 * Unless specified otherwise, read the system clock and
351 * initialize the time.
352 */
353 if (!utc) {
354 gettimeofday(&tv, NULL);
355 tm = gmtime(&tv.tv_sec);
356 minute = tm->tm_min;
357 hour = tm->tm_hour;
358 day = tm->tm_yday + 1;
359 year = tm->tm_year % 100;
360 second = tm->tm_sec;
361
362 /*
363 * Delay the first second so the generator is accurately
364 * aligned with the system clock within one sample (125
365 * microseconds ).
366 */
367 delay(SECOND - tv.tv_usec * 8 / 1000);
368 }
369 memset(code, 0, sizeof(code));
370 switch (encode) {
371
372 /*
373 * For WWV/H and default time, carefully set the signal
374 * generator seconds number to agree with the current time.
375 */
376 case WWV:
377 printf("year %d day %d time %02d:%02d:%02d tone %d\n",
378 year, day, hour, minute, second, tone);
379 snprintf(code, sizeof(code), "%01d%03d%02d%02d%01d",
380 year / 10, day, hour, minute, year % 10);
381 printf("%s\n", code);
382 ptr = 8;
383 for (i = 0; i <= second; i++) {
384 if (progx[i].sw == DEC)
385 ptr--;
386 }
387 break;
388
389 /*
390 * For IRIG the signal generator runs every second, so requires
391 * no additional alignment.
392 */
393 case IRIG:
394 printf("sbs %x year %d day %d time %02d:%02d:%02d\n",
395 0, year, day, hour, minute, second);
396 break;
397 }
398
399 /*
400 * Run the signal generator to generate new timecode strings
401 * once per minute for WWV/H and once per second for IRIG.
402 */
403 while(1) {
404
405 /*
406 * Crank the state machine to propagate carries to the
407 * year of century. Note that we delayed up to one
408 * second for alignment after reading the time, so this
409 * is the next second.
410 */
411 second = (second + 1) % 60;
412 if (second == 0) {
413 minute++;
414 if (minute >= 60) {
415 minute = 0;
416 hour++;
417 }
418 if (hour >= 24) {
419 hour = 0;
420 day++;
421 }
422
423 /*
424 * At year rollover check for leap second.
425 */
426 if (day >= (year & 0x3 ? 366 : 367)) {
427 if (leap) {
428 sec(DATA0);
429 printf("\nleap!");
430 leap = 0;
431 }
432 day = 1;
433 year++;
434 }
435 if (encode == WWV) {
436 snprintf(code, sizeof(code),
437 "%01d%03d%02d%02d%01d", year / 10,
438 day, hour, minute, year % 10);
439 printf("\n%s\n", code);
440 ptr = 8;
441 }
442 }
443 if (encode == IRIG) {
444 snprintf(code, sizeof(code),
445 "%04x%04d%06d%02d%02d%02d", 0, year, day,
446 hour, minute, second);
447 printf("%s\n", code);
448 ptr = 19;
449 }
450
451 /*
452 * Generate data for the second
453 */
454 switch(encode) {
455
456 /*
457 * The IRIG second consists of 20 BCD digits of width-
458 * modulateod pulses at 2, 5 and 8 ms and modulated 50
459 * percent on the 1000-Hz carrier.
460 */
461 case IRIG:
462 for (i = 0; i < 100; i++) {
463 if (i < 10) {
464 sw = progz[i].sw;
465 arg = progz[i].arg;
466 } else {
467 sw = progy[i % 10].sw;
468 arg = progy[i % 10].arg;
469 }
470 switch(sw) {
471
472 case COEF: /* send BCD bit */
473 if (code[ptr] & arg) {
474 peep(M5, 1000, HIGH);
475 peep(M5, 1000, LOW);
476 printf("1");
477 } else {
478 peep(M2, 1000, HIGH);
479 peep(M8, 1000, LOW);
480 printf("0");
481 }
482 break;
483
484 case DEC: /* send IM/PI bit */
485 ptr--;
486 printf(" ");
487 peep(arg, 1000, HIGH);
488 peep(10 - arg, 1000, LOW);
489 break;
490
491 case MIN: /* send data bit */
492 peep(arg, 1000, HIGH);
493 peep(10 - arg, 1000, LOW);
494 printf("M ");
495 break;
496 }
497 if (ptr < 0)
498 break;
499 }
500 printf("\n");
501 break;
502
503 /*
504 * The WWV/H second consists of 9 BCD digits of width-
505 * modulateod pulses 200, 500 and 800 ms at 100-Hz.
506 */
507 case WWV:
508 sw = progx[second].sw;
509 arg = progx[second].arg;
510 switch(sw) {
511
512 case DATA: /* send data bit */
513 sec(arg);
514 break;
515
516 case COEF: /* send BCD bit */
517 if (code[ptr] & arg) {
518 sec(DATA1);
519 printf("1");
520 } else {
521 sec(DATA0);
522 printf("0");
523 }
524 break;
525
526 case LEAP: /* send leap bit */
527 if (leap) {
528 sec(DATA1);
529 printf("L ");
530 } else {
531 sec(DATA0);
532 printf(" ");
533 }
534 break;
535
536 case DEC: /* send data bit */
537 ptr--;
538 sec(arg);
539 printf(" ");
540 break;
541
542 case MIN: /* send minute sync */
543 peep(arg, tone, HIGH);
544 peep(1000 - arg, tone, OFF);
545 break;
546
547 case DUT1: /* send DUT1 bits */
548 if (dut1 & arg)
549 sec(DATA1);
550 else
551 sec(DATA0);
552 break;
553
554 case DST1: /* send DST1 bit */
555 ptr--;
556 if (dst)
557 sec(DATA1);
558 else
559 sec(DATA0);
560 printf(" ");
561 break;
562
563 case DST2: /* send DST2 bit */
564 if (dst)
565 sec(DATA1);
566 else
567 sec(DATA0);
568 break;
569 }
570 }
571 }
572 }
573
574
575 /*
576 * Generate WWV/H 0 or 1 data pulse.
577 */
sec(int code)578 void sec(
579 int code /* DATA0, DATA1, PI */
580 )
581 {
582 /*
583 * The WWV data pulse begins with 5 ms of 1000 Hz follwed by a
584 * guard time of 25 ms. The data pulse is 170, 570 or 770 ms at
585 * 100 Hz corresponding to 0, 1 or position indicator (PI),
586 * respectively. Note the 100-Hz data pulses are transmitted 6
587 * dB below the 1000-Hz sync pulses. Originally the data pulses
588 * were transmited 10 dB below the sync pulses, but the station
589 * engineers increased that to 6 dB because the Heath GC-1000
590 * WWV/H radio clock worked much better.
591 */
592 peep(5, tone, HIGH); /* send seconds tick */
593 peep(25, tone, OFF);
594 peep(code - 30, 100, LOW); /* send data */
595 peep(1000 - code, 100, OFF);
596 }
597
598
599 /*
600 * Generate cycles of 100 Hz or any multiple of 100 Hz.
601 */
peep(int pulse,int freq,int amp)602 void peep(
603 int pulse, /* pulse length (ms) */
604 int freq, /* frequency (Hz) */
605 int amp /* amplitude */
606 )
607 {
608 int increm; /* phase increment */
609 int i, j;
610
611 if (amp == OFF || freq == 0)
612 increm = 10;
613 else
614 increm = freq / 100;
615 j = 0;
616 for (i = 0 ; i < pulse * 8; i++) {
617 switch (amp) {
618
619 case HIGH:
620 buffer[bufcnt++] = ~c6000[j];
621 break;
622
623 case LOW:
624 buffer[bufcnt++] = ~c3000[j];
625 break;
626
627 default:
628 buffer[bufcnt++] = ~0;
629 }
630 if (bufcnt >= BUFLNG) {
631 write(fd, buffer, BUFLNG);
632 bufcnt = 0;
633 }
634 j = (j + increm) % 80;
635 }
636 }
637
638
639 /*
640 * Delay for initial phasing
641 */
delay(int delay)642 void delay (
643 int delay /* delay in samples */
644 )
645 {
646 int samples; /* samples remaining */
647
648 samples = delay;
649 memset(buffer, 0, BUFLNG);
650 while (samples >= BUFLNG) {
651 write(fd, buffer, BUFLNG);
652 samples -= BUFLNG;
653 }
654 write(fd, buffer, samples);
655 }
656