653 lines
16 KiB
C
653 lines
16 KiB
C
/*
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* tg.c generate WWV or IRIG signals for test
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*/
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/*
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* This program can generate audio signals that simulate the WWV/H
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* broadcast timecode. Alternatively, it can generate the IRIG-B
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* timecode commonly used to synchronize laboratory equipment. It is
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* intended to test the WWV/H driver (refclock_wwv.c) and the IRIG
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* driver (refclock_irig.c) in the NTP driver collection.
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*
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* Besides testing the drivers themselves, this program can be used to
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* synchronize remote machines over audio transmission lines or program
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* feeds. The program reads the time on the local machine and sets the
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* initial epoch of the signal generator within one millisecond.
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* Alernatively, the initial epoch can be set to an arbitrary time. This
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* is useful when searching for bugs and testing for correct response to
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* a leap second in UTC. Note however, the ultimate accuracy is limited
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* by the intrinsic frequency error of the codec sample clock, which can
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# reach well over 100 PPM.
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*
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* The default is to route generated signals to the line output
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* jack; the s option on the command line routes these signals to the
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* internal speaker as well. The v option controls the speaker volume
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* over the range 0-255. The signal generator by default uses WWV
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* format; the h option switches to WWVH format and the i option
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* switches to IRIG-B format.
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*
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* Once started the program runs continuously. The default initial epoch
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* for the signal generator is read from the computer system clock when
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* the program starts. The y option specifies an alternate epoch using a
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* string yydddhhmmss, where yy is the year of century, ddd the day of
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* year, hh the hour of day and mm the minute of hour. For instance,
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* 1946Z on 1 January 2006 is 060011946. The l option lights the leap
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* warning bit in the WWV/H timecode, so is handy to check for correct
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* behavior at the next leap second epoch. The remaining options are
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* specified below under the Parse Options heading. Most of these are
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* for testing.
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*
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* During operation the program displays the WWV/H timecode (9 digits)
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* or IRIG timecode (20 digits) as each new string is constructed. The
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* display is followed by the BCD binary bits as transmitted. Note that
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* the transmissionorder is low-order first as the frame is processed
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* left to right. For WWV/H The leap warning L preceeds the first bit.
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* For IRIG the on-time marker M preceeds the first (units) bit, so its
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* code is delayed one bit and the next digit (tens) needs only three
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* bits.
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*
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* The program has been tested with the Sun Blade 1500 running Solaris
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* 10, but not yet with other machines. It uses no special features and
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* should be readily portable to other hardware and operating systems.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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#include <sys/audio.h>
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#include <math.h>
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#include <errno.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <string.h>
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#include <unistd.h>
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#define SECOND 8000 /* one second of 125-us samples */
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#define BUFLNG 400 /* buffer size */
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#define DEVICE "/dev/audio" /* default audio device */
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#define WWV 0 /* WWV encoder */
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#define IRIG 1 /* IRIG-B encoder */
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#define OFF 0 /* zero amplitude */
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#define LOW 1 /* low amplitude */
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#define HIGH 2 /* high amplitude */
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#define DATA0 200 /* WWV/H 0 pulse */
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#define DATA1 500 /* WWV/H 1 pulse */
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#define PI 800 /* WWV/H PI pulse */
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#define M2 2 /* IRIG 0 pulse */
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#define M5 5 /* IRIG 1 pulse */
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#define M8 8 /* IRIG PI pulse */
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/*
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* Companded sine table amplitude 3000 units
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*/
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int c3000[] = {1, 48, 63, 70, 78, 82, 85, 89, 92, 94, /* 0-9 */
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96, 98, 99, 100, 101, 101, 102, 103, 103, 103, /* 10-19 */
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103, 103, 103, 103, 102, 101, 101, 100, 99, 98, /* 20-29 */
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96, 94, 92, 89, 85, 82, 78, 70, 63, 48, /* 30-39 */
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129, 176, 191, 198, 206, 210, 213, 217, 220, 222, /* 40-49 */
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224, 226, 227, 228, 229, 229, 230, 231, 231, 231, /* 50-59 */
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231, 231, 231, 231, 230, 229, 229, 228, 227, 226, /* 60-69 */
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224, 222, 220, 217, 213, 210, 206, 198, 191, 176}; /* 70-79 */
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/*
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* Companded sine table amplitude 6000 units
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*/
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int c6000[] = {1, 63, 78, 86, 93, 98, 101, 104, 107, 110, /* 0-9 */
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112, 113, 115, 116, 117, 117, 118, 118, 119, 119, /* 10-19 */
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119, 119, 119, 118, 118, 117, 117, 116, 115, 113, /* 20-29 */
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112, 110, 107, 104, 101, 98, 93, 86, 78, 63, /* 30-39 */
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129, 191, 206, 214, 221, 226, 229, 232, 235, 238, /* 40-49 */
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240, 241, 243, 244, 245, 245, 246, 246, 247, 247, /* 50-59 */
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247, 247, 247, 246, 246, 245, 245, 244, 243, 241, /* 60-69 */
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240, 238, 235, 232, 229, 226, 221, 214, 206, 191}; /* 70-79 */
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/*
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* Decoder operations at the end of each second are driven by a state
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* machine. The transition matrix consists of a dispatch table indexed
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* by second number. Each entry in the table contains a case switch
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* number and argument.
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*/
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struct progx {
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int sw; /* case switch number */
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int arg; /* argument */
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};
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/*
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* Case switch numbers
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*/
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#define DATA 0 /* send data (0, 1, PI) */
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#define COEF 1 /* send BCD bit */
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#define DEC 2 /* decrement to next digit */
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#define MIN 3 /* minute pulse */
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#define LEAP 4 /* leap warning */
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#define DUT1 5 /* DUT1 bits */
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#define DST1 6 /* DST1 bit */
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#define DST2 7 /* DST2 bit */
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/*
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* WWV/H format (100-Hz, 9 digits, 1 m frame)
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*/
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struct progx progx[] = {
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{MIN, 800}, /* 0 minute sync pulse */
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{DATA, DATA0}, /* 1 */
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{DST2, 0}, /* 2 DST2 */
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{LEAP, 0}, /* 3 leap warning */
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{COEF, 1}, /* 4 1 year units */
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{COEF, 2}, /* 5 2 */
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{COEF, 4}, /* 6 4 */
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{COEF, 8}, /* 7 8 */
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{DEC, DATA0}, /* 8 */
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{DATA, PI}, /* 9 p1 */
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{COEF, 1}, /* 10 1 minute units */
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{COEF, 2}, /* 11 2 */
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{COEF, 4}, /* 12 4 */
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{COEF, 8}, /* 13 8 */
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{DEC, DATA0}, /* 14 */
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{COEF, 1}, /* 15 10 minute tens */
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{COEF, 2}, /* 16 20 */
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{COEF, 4}, /* 17 40 */
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{COEF, 8}, /* 18 80 (not used) */
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{DEC, PI}, /* 19 p2 */
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{COEF, 1}, /* 20 1 hour units */
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{COEF, 2}, /* 21 2 */
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{COEF, 4}, /* 22 4 */
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{COEF, 8}, /* 23 8 */
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{DEC, DATA0}, /* 24 */
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{COEF, 1}, /* 25 10 hour tens */
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{COEF, 2}, /* 26 20 */
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{COEF, 4}, /* 27 40 (not used) */
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{COEF, 8}, /* 28 80 (not used) */
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{DEC, PI}, /* 29 p3 */
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{COEF, 1}, /* 30 1 day units */
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{COEF, 2}, /* 31 2 */
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{COEF, 4}, /* 32 4 */
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{COEF, 8}, /* 33 8 */
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{DEC, DATA0}, /* 34 not used */
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{COEF, 1}, /* 35 10 day tens */
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{COEF, 2}, /* 36 20 */
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{COEF, 4}, /* 37 40 */
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{COEF, 8}, /* 38 80 */
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{DEC, PI}, /* 39 p4 */
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{COEF, 1}, /* 40 100 day hundreds */
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{COEF, 2}, /* 41 200 */
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{COEF, 4}, /* 42 400 (not used) */
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{COEF, 8}, /* 43 800 (not used) */
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{DEC, DATA0}, /* 44 */
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{DATA, DATA0}, /* 45 */
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{DATA, DATA0}, /* 46 */
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{DATA, DATA0}, /* 47 */
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{DATA, DATA0}, /* 48 */
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{DATA, PI}, /* 49 p5 */
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{DUT1, 8}, /* 50 DUT1 sign */
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{COEF, 1}, /* 51 10 year tens */
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{COEF, 2}, /* 52 20 */
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{COEF, 4}, /* 53 40 */
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{COEF, 8}, /* 54 80 */
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{DST1, 0}, /* 55 DST1 */
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{DUT1, 1}, /* 56 0.1 DUT1 fraction */
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{DUT1, 2}, /* 57 0.2 */
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{DUT1, 4}, /* 58 0.4 */
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{DATA, PI}, /* 59 p6 */
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{DATA, DATA0}, /* 60 leap */
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};
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/*
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* IRIG format except first frame (1000 Hz, 20 digits, 1 s frame)
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*/
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struct progx progy[] = {
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{COEF, 1}, /* 0 1 units */
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{COEF, 2}, /* 1 2 */
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{COEF, 4}, /* 2 4 */
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{COEF, 8}, /* 3 8 */
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{DEC, M2}, /* 4 im */
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{COEF, 1}, /* 5 10 tens */
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{COEF, 2}, /* 6 20 */
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{COEF, 4}, /* 7 40 */
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{COEF, 8}, /* 8 80 */
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{DEC, M8}, /* 9 pi */
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};
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/*
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* IRIG format first frame (1000 Hz, 20 digits, 1 s frame)
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*/
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struct progx progz[] = {
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{MIN, M8}, /* 0 pi (second) */
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{COEF, 1}, /* 1 1 units */
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{COEF, 2}, /* 2 2 */
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{COEF, 4}, /* 3 4 */
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{COEF, 8}, /* 4 8 */
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{DEC, M2}, /* 5 im */
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{COEF, 1}, /* 6 10 tens */
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{COEF, 2}, /* 7 20 */
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{COEF, 4}, /* 8 40 */
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{DEC, M8}, /* 9 pi */
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};
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/*
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* Forward declarations
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*/
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void sec(int); /* send second */
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void digit(int); /* encode digit */
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void peep(int, int, int); /* send cycles */
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void delay(int); /* delay samples */
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/*
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* Global variables
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*/
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char buffer[BUFLNG]; /* output buffer */
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int bufcnt = 0; /* buffer counter */
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int second = 0; /* seconds counter */
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int fd; /* audio codec file descriptor */
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int tone = 1000; /* WWV sync frequency */
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int level = AUDIO_MAX_GAIN / 8; /* output level */
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int port = AUDIO_LINE_OUT; /* output port */
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int encode = WWV; /* encoder select */
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int leap = 0; /* leap indicator */
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int dst = 0; /* winter/summer time */
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int dut1 = 0; /* DUT1 correction (sign, magnitude) */
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int utc = 0; /* option epoch */
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/*
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* Main program
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*/
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int
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main(
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int argc, /* command line options */
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char **argv /* poiniter to list of tokens */
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)
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{
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struct timeval tv; /* system clock at startup */
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audio_info_t info; /* Sun audio structure */
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struct tm *tm = NULL; /* structure returned by gmtime */
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char device[50]; /* audio device */
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char code[100]; /* timecode */
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int rval, temp, arg, sw, ptr;
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int minute, hour, day, year;
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int i;
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/*
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* Parse options
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*/
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strcpy(device, DEVICE);
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year = 0;
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while ((temp = getopt(argc, argv, "a:dhilsu:v:y:")) != -1) {
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switch (temp) {
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case 'a': /* specify audio device (/dev/audio) */
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strcpy(device, optarg);
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break;
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case 'd': /* set DST for summer (WWV/H only) */
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dst++;
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break;
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case 'h': /* select WWVH sync frequency */
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tone = 1200;
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break;
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case 'i': /* select irig format */
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encode = IRIG;
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break;
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case 'l': /* set leap warning bit (WWV/H only) */
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leap++;
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break;
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case 's': /* enable speaker */
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port |= AUDIO_SPEAKER;
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break;
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case 'u': /* set DUT1 offset (-7 to +7) */
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sscanf(optarg, "%d", &dut1);
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if (dut1 < 0)
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dut1 = abs(dut1);
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else
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dut1 |= 0x8;
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break;
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case 'v': /* set output level (0-255) */
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sscanf(optarg, "%d", &level);
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break;
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case 'y': /* set initial date and time */
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sscanf(optarg, "%2d%3d%2d%2d", &year, &day,
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&hour, &minute);
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utc++;
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break;
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defult:
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printf("invalid option %c\n", temp);
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break;
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}
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}
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/*
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* Open audio device and set options
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*/
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fd = open("/dev/audio", O_WRONLY);
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if (fd <= 0) {
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printf("audio open %s\n", strerror(errno));
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exit(1);
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}
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rval = ioctl(fd, AUDIO_GETINFO, &info);
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if (rval < 0) {
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printf("audio control %s\n", strerror(errno));
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exit(0);
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}
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info.play.port = port;
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info.play.gain = level;
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info.play.sample_rate = SECOND;
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info.play.channels = 1;
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info.play.precision = 8;
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info.play.encoding = AUDIO_ENCODING_ULAW;
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printf("port %d gain %d rate %d chan %d prec %d encode %d\n",
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info.play.port, info.play.gain, info.play.sample_rate,
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info.play.channels, info.play.precision,
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info.play.encoding);
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ioctl(fd, AUDIO_SETINFO, &info);
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/*
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* Unless specified otherwise, read the system clock and
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* initialize the time.
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*/
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if (!utc) {
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gettimeofday(&tv, NULL);
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tm = gmtime(&tv.tv_sec);
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minute = tm->tm_min;
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hour = tm->tm_hour;
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day = tm->tm_yday + 1;
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year = tm->tm_year % 100;
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second = tm->tm_sec;
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/*
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* Delay the first second so the generator is accurately
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* aligned with the system clock within one sample (125
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* microseconds ).
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*/
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delay(SECOND - tv.tv_usec * 8 / 1000);
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}
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memset(code, 0, sizeof(code));
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switch (encode) {
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/*
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* For WWV/H and default time, carefully set the signal
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* generator seconds number to agree with the current time.
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*/
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case WWV:
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printf("year %d day %d time %02d:%02d:%02d tone %d\n",
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year, day, hour, minute, second, tone);
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sprintf(code, "%01d%03d%02d%02d%01d", year / 10, day,
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hour, minute, year % 10);
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printf("%s\n", code);
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ptr = 8;
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for (i = 0; i <= second; i++) {
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if (progx[i].sw == DEC)
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ptr--;
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}
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break;
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/*
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* For IRIG the signal generator runs every second, so requires
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* no additional alignment.
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*/
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case IRIG:
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printf("sbs %x year %d day %d time %02d:%02d:%02d\n",
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0, year, day, hour, minute, second);
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break;
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}
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/*
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* Run the signal generator to generate new timecode strings
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* once per minute for WWV/H and once per second for IRIG.
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*/
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while(1) {
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/*
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* Crank the state machine to propagate carries to the
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* year of century. Note that we delayed up to one
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* second for alignment after reading the time, so this
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* is the next second.
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*/
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second = (second + 1) % 60;
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if (second == 0) {
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minute++;
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if (minute >= 60) {
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minute = 0;
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hour++;
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}
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if (hour >= 24) {
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hour = 0;
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day++;
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}
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/*
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* At year rollover check for leap second.
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*/
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if (day >= (year & 0x3 ? 366 : 367)) {
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if (leap) {
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sec(DATA0);
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printf("\nleap!");
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leap = 0;
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}
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day = 1;
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year++;
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}
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if (encode == WWV) {
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sprintf(code, "%01d%03d%02d%02d%01d",
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year / 10, day, hour, minute, year %
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10);
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printf("\n%s\n", code);
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ptr = 8;
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}
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}
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if (encode == IRIG) {
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sprintf(code, "%04x%04d%06d%02d%02d%02d", 0,
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year, day, hour, minute, second);
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printf("%s\n", code);
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ptr = 19;
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}
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/*
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* Generate data for the second
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*/
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switch(encode) {
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/*
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* The IRIG second consists of 20 BCD digits of width-
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* modulateod pulses at 2, 5 and 8 ms and modulated 50
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* percent on the 1000-Hz carrier.
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*/
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case IRIG:
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for (i = 0; i < 100; i++) {
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if (i < 10) {
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sw = progz[i].sw;
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arg = progz[i].arg;
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} else {
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sw = progy[i % 10].sw;
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arg = progy[i % 10].arg;
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}
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switch(sw) {
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case COEF: /* send BCD bit */
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if (code[ptr] & arg) {
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peep(M5, 1000, HIGH);
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peep(M5, 1000, LOW);
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printf("1");
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} else {
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peep(M2, 1000, HIGH);
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peep(M8, 1000, LOW);
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printf("0");
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}
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break;
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case DEC: /* send IM/PI bit */
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ptr--;
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printf(" ");
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peep(arg, 1000, HIGH);
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peep(10 - arg, 1000, LOW);
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break;
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case MIN: /* send data bit */
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peep(arg, 1000, HIGH);
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peep(10 - arg, 1000, LOW);
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printf("M ");
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break;
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}
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if (ptr < 0)
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break;
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}
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printf("\n");
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break;
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/*
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|
* The WWV/H second consists of 9 BCD digits of width-
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* modulateod pulses 200, 500 and 800 ms at 100-Hz.
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*/
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case WWV:
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sw = progx[second].sw;
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arg = progx[second].arg;
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switch(sw) {
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|
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case DATA: /* send data bit */
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sec(arg);
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break;
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|
|
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case COEF: /* send BCD bit */
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if (code[ptr] & arg) {
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sec(DATA1);
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printf("1");
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} else {
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sec(DATA0);
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printf("0");
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}
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|
break;
|
|
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case LEAP: /* send leap bit */
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|
if (leap) {
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|
sec(DATA1);
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|
printf("L ");
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|
} else {
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|
sec(DATA0);
|
|
printf(" ");
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|
}
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|
break;
|
|
|
|
case DEC: /* send data bit */
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|
ptr--;
|
|
sec(arg);
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|
printf(" ");
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|
break;
|
|
|
|
case MIN: /* send minute sync */
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|
peep(arg, tone, HIGH);
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|
peep(1000 - arg, tone, OFF);
|
|
break;
|
|
|
|
case DUT1: /* send DUT1 bits */
|
|
if (dut1 & arg)
|
|
sec(DATA1);
|
|
else
|
|
sec(DATA0);
|
|
break;
|
|
|
|
case DST1: /* send DST1 bit */
|
|
ptr--;
|
|
if (dst)
|
|
sec(DATA1);
|
|
else
|
|
sec(DATA0);
|
|
printf(" ");
|
|
break;
|
|
|
|
case DST2: /* send DST2 bit */
|
|
if (dst)
|
|
sec(DATA1);
|
|
else
|
|
sec(DATA0);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* Generate WWV/H 0 or 1 data pulse.
|
|
*/
|
|
void sec(
|
|
int code /* DATA0, DATA1, PI */
|
|
)
|
|
{
|
|
/*
|
|
* The WWV data pulse begins with 5 ms of 1000 Hz follwed by a
|
|
* guard time of 25 ms. The data pulse is 170, 570 or 770 ms at
|
|
* 100 Hz corresponding to 0, 1 or position indicator (PI),
|
|
* respectively. Note the 100-Hz data pulses are transmitted 6
|
|
* dB below the 1000-Hz sync pulses. Originally the data pulses
|
|
* were transmited 10 dB below the sync pulses, but the station
|
|
* engineers increased that to 6 dB because the Heath GC-1000
|
|
* WWV/H radio clock worked much better.
|
|
*/
|
|
peep(5, tone, HIGH); /* send seconds tick */
|
|
peep(25, tone, OFF);
|
|
peep(code - 30, 100, LOW); /* send data */
|
|
peep(1000 - code, 100, OFF);
|
|
}
|
|
|
|
|
|
/*
|
|
* Generate cycles of 100 Hz or any multiple of 100 Hz.
|
|
*/
|
|
void peep(
|
|
int pulse, /* pulse length (ms) */
|
|
int freq, /* frequency (Hz) */
|
|
int amp /* amplitude */
|
|
)
|
|
{
|
|
int increm; /* phase increment */
|
|
int i, j;
|
|
|
|
if (amp == OFF || freq == 0)
|
|
increm = 10;
|
|
else
|
|
increm = freq / 100;
|
|
j = 0;
|
|
for (i = 0 ; i < pulse * 8; i++) {
|
|
switch (amp) {
|
|
|
|
case HIGH:
|
|
buffer[bufcnt++] = ~c6000[j];
|
|
break;
|
|
|
|
case LOW:
|
|
buffer[bufcnt++] = ~c3000[j];
|
|
break;
|
|
|
|
default:
|
|
buffer[bufcnt++] = ~0;
|
|
}
|
|
if (bufcnt >= BUFLNG) {
|
|
write(fd, buffer, BUFLNG);
|
|
bufcnt = 0;
|
|
}
|
|
j = (j + increm) % 80;
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* Delay for initial phasing
|
|
*/
|
|
void delay (
|
|
int delay /* delay in samples */
|
|
)
|
|
{
|
|
int samples; /* samples remaining */
|
|
|
|
samples = delay;
|
|
memset(buffer, 0, BUFLNG);
|
|
while (samples >= BUFLNG) {
|
|
write(fd, buffer, BUFLNG);
|
|
samples -= BUFLNG;
|
|
}
|
|
write(fd, buffer, samples);
|
|
}
|