4 files changed, 118 insertions, 0 deletions

diff --git a/prog/fourier/.gdb_history b/prog/fourier/.gdb_history
new file mode 100644
index 0000000..b3967fe
--- /dev/null
+++ b/prog/fourier/.gdb_history
@@ -0,0 +1,7 @@
+bt
+list
+p najv
+p val
+quit
+q
+quit
diff --git a/prog/fourier/.gitignore b/prog/fourier/.gitignore
new file mode 100644
index 0000000..90989b8
--- /dev/null
+++ b/prog/fourier/.gitignore
@@ -0,0 +1,2 @@
+a.out
+core
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;
+	}
+}
diff --git a/prog/fourier/ldft.c b/prog/fourier/ldft.c
new file mode 100644
index 0000000..1420bc8
--- /dev/null
+++ b/prog/fourier/ldft.c
@@ -0,0 +1,8 @@
+// lying discrete fourier transformation
+// this has no mathematical proofs behind it
+// key difference is that it operates in a sliding window mode without holding the window buffer itself
+// instead it works in a faucet way, with a single scalar complex state for every frequency that you want to monitor stored and operates with this state one sample at a time
+// absolute value of the state directly correlates with freqency domain ordinate value
+// temelji na diskretni fourierjevi transformaciji in na weighted moving average
+// namesto izhodnega vektorja ob množenju  ...
+// nvm najprej bom poizkusil narediti dft po krščansko, potem se bomo šli glupe optimizacije