Unterschiede

Hier werden die Unterschiede zwischen zwei Versionen angezeigt.

--- projekte:iqmix [2014/02/04 16:30] – [Ansteuerung] thasti
+++ projekte:iqmix [2014/02/04 19:19] – [Ansteuerung] yc
@@ Zeile 382: / Zeile 382: @@
 Um normale Audio-Dateien FM-moduliert als I/Q-Signale mit einer Soundkarte ausgeben zu können, gibt es folgendes kleines Tool: **fmmod**
-<code c fmmod.c>
+<file c fmmod.c>
-extern> wiki:.fmmod.c
+/* complex frequency modulator for i/q signal processing
-</code>
+ * Sebastian Weiss <dl3yc@darc.de>
+ * Di 4. Feb 16:10:01 CET 2014
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <sndfile.h>
+#include <math.h>
+#define BUFFER_LEN  1024
+void usage(void)
+{
+    printf("Usage: fmmod inputfile outputfile [carrier] [freqdev]\n \
+            inputfile: path to input file(needs to be single channel)\n \
+            outputfile: path to output file\n \
+            carrier: carrier frequency in Hz(standard: 0.0)\n \
+            freqdev: frequency deviation in Hz(standard: 3000)\n");
+}
+void process_data(double *data, int count, int fs, double fc, double freqdev)
+{
+    static double old_phase = 0.0;
+    double cumsum[BUFFER_LEN];
+    double phase;
+    int i;
+    if (count == 0)
+        return;
+    cumsum[0] = data[0]/fs;
+    for (i = 1; i < count; i++) {
+        cumsum[i] = cumsum[i-1] + data[i]/fs;
+    }
+    for (i=0; i < count; i++) {
+        phase = 2*M_PI*fc/fs*(i+1) + 2*M_PI*freqdev*cumsum[i] + old_phase;
+        data[2*i] = cos(phase);
+        data[2*i + 1] = -sin(phase);
+    }
+    old_phase = fmod(phase, 2*M_PI);
+    return;
+}
+int main(int argc, char *argv[])
+{
+    static double data[2*BUFFER_LEN];
+    SNDFILE *infile, *outfile;
+    SF_INFO sfinfo;
+    int readcount;
+    double carrier;
+    double freqdev;
+    if ((argc > 5) || (argc < 3)) {
+        usage();
+        return 1;
+    }
+    freqdev = (argc == 5) ? atof(argv[4]) : 3000.0;
+    carrier = (argc > 3) ? atof(argv[3]) : 0.0;
+    infile = sf_open(argv[1], SFM_READ, &sfinfo);
+    if (!infile) {
+        printf("%s: Not able to open input file %s\n", argv[0], argv[1]);
+        sf_perror(NULL);
+        return 1;
+    }
+    if (sfinfo.channels > 1) {
+        printf("%s: Not able to process more than 1 channel\n", argv[0]);
+        return 1;
+    }
+    sfinfo.channels = 2;
+    outfile = sf_open(argv[2], SFM_WRITE, &sfinfo);
+    if (!outfile) {
+        printf("%s: Not able to open output file %s\n", argv[0], argv[2]);
+        sf_perror(NULL);
+        return 1;
+    }
+    while ((readcount = sf_read_double(infile, data, BUFFER_LEN))) {
+        process_data(data, readcount, sfinfo.samplerate, carrier, freqdev);
+        sf_write_double(outfile, data, 2*readcount);
+    }
+    sf_close(infile);
+    sf_write_sync(outfile);
+    sf_close(outfile);
+    return 0;
+}
+</file>