diff options
Diffstat (limited to 'prog/fourier/dft.c')
| -rw-r--r-- | prog/fourier/dft.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/prog/fourier/dft.c b/prog/fourier/dft.c new file mode 100644 index 0000000..598a7b3 --- /dev/null +++ b/prog/fourier/dft.c @@ -0,0 +1,101 @@ +// v stdin piši S8 zvočne podatke z 8000 vzorci na sekundo +// frekvence: +// 2100 Hz BAND +// 800 Hz MONI +// 1000 Hz CALL +// 1450 Hz VFO/MR +// 1750 Hz A/B +// DTMF: +// 1209 Hz 1336 Hz 1477 Hz 1633 Hz +// 697 1 2 3 A +// 770 4 5 6 B +// 852 7 8 9 C +// 941 * 0 # D +// ffmpeg -f alsa -ac 1 -i hw:5 -f s8 -ar 8000 - | ./a.out +#include <stdio.h> +#include <stdlib.h> +#include <math.h> +#include <complex.h> +#include <error.h> +#include <errno.h> +#include <sys/param.h> // for MIN, MAX +int main (void) { + if (setvbuf(stdout, NULL, _IOFBF, 0)) + error_at_line(1, errno, __FILE__, __LINE__, "setvbuf"); +#define SAMPLES 256 + int samples[SAMPLES] = { 0 }; + double povprečje = 0; + int frekvence[] = {1209, 1336, 1477, 1633, 697, 770, 852, 941, 2100, 800, 1000, 1450, 1750}; + #define FREKVENC 13 + // int frekvence[] = {2100, 800, 1000, 1450, 1750, 1208, 1209, 1210, 1335, 1336, 1337, 1476, 1477, 1478, 1632, 1633, 1634, 696, 697, 698, 769, 770, 771, 851, 852, 853, 940, 941, 942}; +/* #define FREKVENC 60 + int frekvence[FREKVENC+1]; + for (int i = 0; i < FREKVENC; i++) + // frekvence[i] = 1000-(FREKVENC*10/2)+i*10; + frekvence[i] = i*100; */ + complex sums[FREKVENC] = { 0 }; + unsigned sample = 0; + int received = 0; + char znak = '\0'; + while ((received = getchar()) != EOF) { + unsigned char intermed = received; + char recvd = *(char *) &intermed; + povprečje = (povprečje*SAMPLES+abs(recvd)-abs(samples[sample % SAMPLES]))/SAMPLES; + if (!(sample % SAMPLES)) + printf("\033[2J\npovprečje: %f\n", povprečje); + for (int frekvenca = 0; frekvenca < FREKVENC; frekvenca++) { +#define RATE 8000 + // sums[frekvenca] -= (complex) samples[sample % SAMPLES]*cpow(M_E, (complex) -2*M_PI*I*(complex) frekvence[frekvenca]/(complex) RATE); + sums[frekvenca] += recvd*cpow(M_E, -2*M_PI*I*frekvence[frekvenca]*sample/RATE); + sums[frekvenca] -= samples[sample % SAMPLES]*cpow(M_E, -2*M_PI*I*frekvence[frekvenca]*(sample-SAMPLES)/RATE); + if (!(sample % SAMPLES)) { + printf("%d\t", frekvence[frekvenca]); + // for (int i = 0; i < pow(cabs(sums[frekvenca])/100, 2)/100; i++) + for (int i = 0; i < cabs(sums[frekvenca])/256; i++) + printf("#"); + printf("\n"); + } + } + if (!(sample % SAMPLES)) { + int najv[3] = {0}; + double val[3] = {0}; + for (int i = 0; i < FREKVENC; i++) + for (int j = 0; j < 3; j++) + if (cabs(sums[i]) > val[j]) { + for (int k = 2; k > j; k--) { + najv[k] = najv[k-1]; + val[k] = val[k-1]; + } + najv[j] = i; + val[j] = cabs(sums[i]); + break; + } + char trenutni = '\0'; + if (val[1] > val[0]/3 && val[2] < val[1]/3) { + int večja = MAX(frekvence[najv[0]], frekvence[najv[1]]); + int manjša = MIN(frekvence[najv[0]], frekvence[najv[1]]); + char znaki[4][4] = {{'1', '2', '3', 'A'}, {'4', '5', '6', 'B'}, {'7', '8', '9', 'C'}, {'*', '0', '#', 'D'}}; + int getidx (int freq) { + int i; + for (i = 0; i < 8; i++) + if (freq == frekvence[i]) + return i%4; + return -1; + } + if (getidx(manjša) == -1 || getidx(večja) == -1) + trenutni = '\0'; + else + trenutni = znaki[getidx(manjša)][getidx(večja)]; + } + if (val[1] < val[0]/3 && najv[0] > 7) { + char znaki[] = "PSZVM"; + trenutni = znaki[najv[0]-8]; + } + if (znak == trenutni && znak) + printf("tipka: %c\n", znak); + znak = trenutni; + fflush(stdout); + } + samples[sample++ % SAMPLES] = recvd; + } +} |