snapshot

libraries/audio-tools/examples/examples-dsp/examples-maximilian/05-FM1/05-FM1.ino

@@ -0,0 +1,52 @@
+// One way of thinking about FM synthesis is to see it as vibrato.
+// You make a pitch, then vary it up and down at some rate.
+// You can change the speed of the pitch variation (modulation frequency), and also the amount of variation (modulation index).
+// In FM, usually only one of the waveforms - the carrier that provides the initial pitch - is sent to the output.
+// The frequency of the the carrier wave is continually adjusted at a rate equal to the frequency of the second wave (the modulator).
+// So at any given point in time, the frequency of the carrier can increase by an amount equal to the current amp of the modulator.
+// This has some interesting effects.
+
+#include "AudioTools.h"
+#include "AudioTools/AudioLibs/MaximilianDSP.h"
+
+// Define Arduino output
+I2SStream out;
+Maximilian maximilian(out);
+// Maximilian
+maxiOsc mySine,myOtherSine;//Two oscillators
+
+
+void setup() {//some inits
+  // setup logging
+  Serial.begin(115200);
+  AudioToolsLogger.begin(Serial, AudioToolsLogLevel::Info);
+
+  // setup Aduio output
+  auto cfg = out.defaultConfig(TX_MODE);
+  out.begin(cfg);
+  maximilian.begin(cfg);
+}
+
+void play(float *output) {
+    
+    // In this example, the 'myOtherSine.sinewave' is at an amplitude of 1, it's original amplitude.
+    // This is pretty simple and not too useful.
+    //output[0]=mySine.sinewave(440*myOtherSine.sinewave(1));
+    
+    // Perhaps you should comment out the above line and uncomment the below one instead
+    // It shows how the frequency of the carrier is altered by ADDING a second waveform to its frequency value.
+    // The carrier frequency is 440, and the modulation frequency is 1.
+    // It also shows how the modulation index works. In this case the modulation index is 100
+    // Try adjusting the modolation index. Also, try altering the modulation frequency.
+    output[0]=mySine.sinewave(440+(myOtherSine.sinewave(1)*100));
+    output[1]=output[0];
+
+}
+
+// In complex FM systems you can have lots of modulators stacked together in interesting ways, and theoretically this can make any sound.
+// John Chowning is the guy you probably want to talk to about that.
+
+// Arduino loop
+void loop() {
+    maximilian.copy();
+}