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authorAnton Luka Šijanec <anton@sijanec.eu>2023-04-23 02:14:48 +0200
committerAnton Luka Šijanec <anton@sijanec.eu>2023-04-23 02:14:48 +0200
commit1bb57cc0ceb60872ab1994015611ee4ceeda6681 (patch)
tree570a845fb6fb2d4697d4bbb5ff8eafeeb1b1a350 /prog/fourier/dft.c
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-rw-r--r--prog/fourier/dft.c101
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;
+ }
+}