updates

lib/fm_modulator.c

@@ -0,0 +1,13 @@
+#include "fm_modulator.h"
+
+void init_fm_modulator(FMModulator *fm, float frequency, float deviation, float sample_rate) {
+    fm->frequency = frequency;
+    fm->deviation = deviation;
+    init_oscillator(&fm->osc, frequency, sample_rate);
+}
+
+float modulate_fm(FMModulator *fm, float sample) {
+    float inst_freq = fm->frequency+(sample*fm->deviation);
+    change_oscillator_frequency(&fm->osc, inst_freq);
+    return get_oscillator_sin_sample(&fm->osc);
+}

lib/fm_modulator.h

@@ -0,0 +1,11 @@
+#include "oscillator.h"
+
+typedef struct
+{
+    float frequency;
+    float deviation;
+    Oscillator osc;
+} FMModulator;
+
+void init_fm_modulator(FMModulator *fm, float frequency, float deviation, float sample_rate);
+float modulate_fm(FMModulator *fm, float sample);

src/crosby_stereo_coder.c

@@ -74,12 +74,12 @@ int main() {
     };
 
     pa_buffer_attr input_buffer_atr = {
-        .maxlength = 4096, // You can lower this to 512, but this is fine, it's sub-second delay, you're probably not gonna notice unless you're looking for it
+        .maxlength = 8192,
-	    .fragsize = 2048
+	    .fragsize = 4096
     };
     pa_buffer_attr output_buffer_atr = {
-        .maxlength = 4096,
+        .maxlength = 8192,
-        .tlength = 2048,
+        .tlength = 4096,
 	    .prebuf = 0
     };
 

src/features.h

@@ -1,2 +1,2 @@
 // #define PREEMPHASIS
-#define LPF
+// #define LPF

src/polar_stereo_coder.c

@@ -73,12 +73,12 @@ int main() {
     };
 
     pa_buffer_attr input_buffer_atr = {
-        .maxlength = 4096, // You can lower this to 512, but this is fine, it's sub-second delay, you're probably not gonna notice unless you're looking for it
+        .maxlength = 8192,
-	    .fragsize = 2048
+	    .fragsize = 4096
     };
     pa_buffer_attr output_buffer_atr = {
-        .maxlength = 4096,
+        .maxlength = 8192,
-        .tlength = 2048,
+        .tlength = 4096,
 	    .prebuf = 0
     };
 

src/sca_mod.c

@@ -10,6 +10,7 @@
 #include "../lib/constants.h"
 #include "../lib/oscillator.h"
 #include "../lib/filters.h"
+#include "../lib/fm_modulator.h"
 
 // Features
 #include "features.h"
@@ -63,12 +64,12 @@ int main() {
     };
 
     pa_buffer_attr input_buffer_atr = {
-        .maxlength = 4096, // You can lower this to 512, but this is fine, it's sub-second delay, you're probably not gonna notice unless you're looking for it
+        .maxlength = 8192,
-	    .fragsize = 2048
+	    .fragsize = 4096
     };
     pa_buffer_attr output_buffer_atr = {
-        .maxlength = 4096,
+        .maxlength = 8192,
-        .tlength = 2048,
+        .tlength = 4096,
 	    .prebuf = 0
     };
 
@@ -109,8 +110,8 @@ int main() {
         return 1;
     }
 
-    Oscillator osc;
+    FMModulator mod;
-    init_oscillator(&osc, FREQUENCY, SAMPLE_RATE);
+    init_fm_modulator(&mod, FREQUENCY, DEVIATION, SAMPLE_RATE);
 #ifdef PREEMPHASIS
     Emphasis preemp;
     init_emphasis(&preemp, PREEMPHASIS_TAU, SAMPLE_RATE);
@@ -154,8 +155,7 @@ int main() {
 #endif
 #endif
 
-            change_oscillator_frequency(&osc, (FREQUENCY+((current_input*VOLUME_AUDIO)*DEVIATION)));
+            signal[i] = modulate_fm(&mod, current_input)*VOLUME;
-            signal[i] = get_oscillator_sin_sample(&osc)*VOLUME;
         }
 
         if (pa_simple_write(output_device, signal, sizeof(signal), &pulse_error) < 0) {

src/ssb_stereo_coder.c

@@ -76,12 +76,12 @@ int main() {
     };
 
     pa_buffer_attr input_buffer_atr = {
-        .maxlength = 4096, // You can lower this to 512, but this is fine, it's sub-second delay, you're probably not gonna notice unless you're looking for it
+        .maxlength = 8192,
-	    .fragsize = 2048
+	    .fragsize = 4096
     };
     pa_buffer_attr output_buffer_atr = {
-        .maxlength = 4096,
+        .maxlength = 8192,
-        .tlength = 2048,
+        .tlength = 4096,
 	    .prebuf = 0
     };
 

src/stereo_coder.c

@@ -74,12 +74,12 @@ int main() {
     };
 
     pa_buffer_attr input_buffer_atr = {
-        .maxlength = 4096, // You can lower this to 512, but this is fine, it's sub-second delay, you're probably not gonna notice unless you're looking for it
+        .maxlength = 8192,
-	    .fragsize = 2048
+	    .fragsize = 4096
     };
     pa_buffer_attr output_buffer_atr = {
-        .maxlength = 4096,
+        .maxlength = 8192,
-        .tlength = 2048,
+        .tlength = 4096,
 	    .prebuf = 0
     };
 

src/stereo_sca_mod.c

@@ -10,6 +10,7 @@
 #include "../lib/constants.h"
 #include "../lib/oscillator.h"
 #include "../lib/filters.h"
+#include "../lib/fm_modulator.h"
 
 // Features
 #include "features.h"
@@ -74,12 +75,12 @@ int main() {
     };
 
     pa_buffer_attr input_buffer_atr = {
-        .maxlength = 4096, // You can lower this to 512, but this is fine, it's sub-second delay, you're probably not gonna notice unless you're looking for it
+        .maxlength = 8192,
-	    .fragsize = 2048
+	    .fragsize = 4096
     };
     pa_buffer_attr output_buffer_atr = {
-        .maxlength = 4096,
+        .maxlength = 8192,
-        .tlength = 2048,
+        .tlength = 4096,
 	    .prebuf = 0
     };
 
@@ -120,9 +121,9 @@ int main() {
         return 1;
     }
 
-    Oscillator osc_mono, osc_stereo;
+    FMModulator mod_mono, mod_stereo;
-    init_oscillator(&osc_mono, 67000, SAMPLE_RATE);
+    init_fm_modulator(&mod_mono, 67000, 6000, SAMPLE_RATE);
-    init_oscillator(&osc_stereo, 80000, SAMPLE_RATE);
+    init_fm_modulator(&mod_stereo, 80000, 6000, SAMPLE_RATE);
 #ifdef PREEMPHASIS
     Emphasis preemp_l, preemp_r;
     init_emphasis(&preemp_l, PREEMPHASIS_TAU, SAMPLE_RATE);
@@ -181,10 +182,8 @@ int main() {
             float mono = (current_left_input+current_right_input)/2.0f;
             float stereo = (current_left_input-current_right_input)/2.0f;
 
-            change_oscillator_frequency(&osc_mono, (67000+(mono*6000)));
+            signal[i] = modulate_fm(&mod_mono, mono)*MONO_VOLUME+
-            change_oscillator_frequency(&osc_stereo, (80000+(stereo*6000)));
+                modulate_fm(&mod_stereo, stereo)*STEREO_VOLUME;
-            signal[i] = get_oscillator_sin_sample(&osc_mono)*MONO_VOLUME+
-                get_oscillator_sin_sample(&osc_stereo)*STEREO_VOLUME;
         }
 
         if (pa_simple_write(output_device, signal, sizeof(signal), &pulse_error) < 0) {