QAM add constellation plot

QAM/qam.c

@@ -3,9 +3,11 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <complex.h>
-#include "../WAV/wav.h"
+#include "../wav/wav.h"
 #include "../files/files.h"
+#include "../plot/plot_constellation.h"
 #include <string.h>
+#include <SDL2/SDL.h>
 
 #define A 10000
 
@@ -73,7 +75,7 @@ void bits_to_symbols (qam_system* qam, uint8_t* bits, int nb_bits, double comple
     }
 }
 
-// Modulation qam
+// Modulation QAM 
 void modulate (qam_system* qam, double complex* symbols, int nb_symbols, double complex* s) {
     for (int k = 0; k < nb_symbols; k++) {
         double complex iq = symbols[k];
@@ -83,8 +85,8 @@ void modulate (qam_system* qam, double complex* symbols, int nb_symbols, double
     }
 }
 
-// Demodulation qam
-void demodulate(qam_system* qam, double complex* s, int nb_symbols, uint8_t* bits_hat, double sigma) {
+// Demodulation QAM 
+void demodulate(qam_system* qam, double complex* s, int nb_symbols, uint8_t* bits_hat) {
     for (int k = 0; k < nb_symbols; k++) {
         double complex r = 0;
         for (int n = 0; n < qam->N; n++) {
@@ -128,8 +130,21 @@ void demodulate(qam_system* qam, double complex* s, int nb_symbols, uint8_t* bit
     }
 }
 
+double complex* demodulate_points(qam_system* qam, double complex* s, int nb_symbols) {
+    double complex* points = malloc(sizeof(double complex) * nb_symbols);
+    for (int k = 0; k < nb_symbols; k++) {
+        double complex r = 0;
+        for (int n = 0; n < qam->N; n++) {
+            r += s[k * qam->N + n] * cexp(-2 * I * M_PI * qam->Fc * ((double)n / qam->Fs));
+        }
+        r /= qam->N;
+        points[k] = r;
+    }
+    return points;
+}
+
 // Libération de la mémoire
-void free_constellation(qam_system *qam) {
+void free_constellation(qam_system* qam) {
     int sm = (int)sqrt(qam->M);
     for (int i = 0; i < sm; i++)
         free(qam->constellation[i]);
@@ -143,50 +158,46 @@ int main (int argc, char *argv[]) {
     }
 
     qam_system qam;
-    qam.M = 256;
+    qam.M = 64;
     qam.k = (int)log2((double)(qam.M));
     qam.Fs = 44100;
-    qam.Ts = 0.003;
+    qam.Ts = 0.0003;
     qam.N = (int)qam.Fs * qam.Ts;
     qam.Fc = 2000;
     init_constellation(&qam);
 
-    // Nombre de bit multiple de k sinon remplir de zero jusqu'a ce que ce le soit
-    //int bits[16] = {1,0,1,1,  0,1,1,0,  1,1,0,0,  0,0,0,1};
-    //int nb_bits = 16;
-    //int nb_symbols = 16 / qam.k;
-
-    printf("Lecture du fichier\n");
+    printf("Lecture du fichier...\n");
     // Lecture du fichier et conversion en bits
     const char *input_filename = argv[1];
     bit_array input_bits = file_to_bits(input_filename);
     size_t nb_symbols = input_bits.nb_bits / qam.k;
 
-    printf("Mise en forme des symboles\n");
+    printf("Mise en forme des symboles...\n");
     // Mise en forme des symboles
     double complex *symbols = malloc(sizeof(double complex) * nb_symbols);
     bits_to_symbols(&qam, input_bits.bits, input_bits.nb_bits, symbols);
 
-    printf("Modulation\n");
+    printf("Modulation...\n");
     // Modulation QAM 
     int total_samples = qam.N * nb_symbols;
     double complex* s = (double complex*)malloc(sizeof(double complex) * total_samples);
     modulate(&qam, symbols, nb_symbols, s);
+
     // Ajout du bruit 
     double signal_power = (2.0/3.0)*(qam.M-1); // puissance moyenne avant échelle
     double snr_dB = -27; // Signal to noise ratio
     double snr_lin = pow(10.0, snr_dB / 10.0);
     double sigma = sqrt(signal_power / snr_lin);
-    printf("Ajout du bruit \n       puissance du signal : %f\n       SNR db : %f\n       sigma : %f\n", signal_power, snr_dB, sigma);
-    add_noise(s, total_samples, sigma);
+    printf("Ajout du bruit... \n       puissance du signal : %f\n       SNR db : %f\n       sigma : %f\n", signal_power, snr_dB, sigma);
+    add_noise(s, total_samples, 1875);
 
-    printf("Demodulation\n");
+    printf("Demodulation...\n");
 
     // Demodulation QAM
     bit_array output_bits;
     output_bits.nb_bits = input_bits.nb_bits;
     output_bits.bits = (uint8_t*)malloc(output_bits.nb_bits);
-    demodulate(&qam, s, nb_symbols, output_bits.bits, 0.0);
+    demodulate(&qam, s, nb_symbols, output_bits.bits);
 
     printf("Ecriture...\n");
     // Ecriture du fichier de Demodulation
@@ -199,9 +210,18 @@ int main (int argc, char *argv[]) {
     for (int i = 0; i < total_samples; i++) {
        si[i] = cimag(s[i]); 
     }
-    write_wav("s.wav", si, total_samples);
+    write_wav("output.wav", si, total_samples);
+
+    // Plot
+    printf("Ploting...");
+    plot_t plot;
+    plot_init(&plot, 1400, 1400, 0.04);
+    plot_draw_constellation(&plot, qam.constellation, qam.M);
+    SDL_Color red = {255, 0, 0, 255};
+    plot_draw_points_animated(&plot, demodulate_points(&qam, s, nb_symbols), nb_symbols, red, 5);
 
     // Libération mémoire
+    plot_close(&plot);
     free_bit_array(&input_bits);
     free_bit_array(&output_bits);
     free(symbols);