seiichi horie / Mbed 2 deprecated synthesizer_f746

Synthesizer based on the Unzen / Nucleo F746ZG

Dependencies:   amakusa mbed-dsp mbed shimabara ukifune unzen_nucleo_f746

Fork of skeleton_unzen_nucleo_f746 by seiichi horie

雲仙フレームワークのテストとして作っているプロジェクトです。中身はどんどん変っていきます。 説明はDSP空挺団の「シンセサイザー」カテゴリーを参照してください。初回は「ドッグフードを食べる」です。

Diff: svfilter.cpp

Revision:
22:dc2cbe8db9d9
Parent:
21:dcfbe6d2a6d3
Child:
25:d15dd7b9101c
--- a/svfilter.cpp	Sat Feb 04 15:05:44 2017 +0000
+++ b/svfilter.cpp	Sun Feb 05 06:16:49 2017 +0000
@@ -52,16 +52,32 @@
     
     for ( int i= 0; i<blockSize; i++ )
     {
+            // calc the filter
         bp = this->d1;
         lp = bp * this->f + this->d2;
         hp = pSrc[i] - this->q * bp - lp;
         
+            // update delay 
         this->d1 += hp * this->f;
         this->d2 = lp;
+        
+            // mode dependent output
+        switch ( this->mode )
+        {
+        case lpf :
+            pDst[i] = lp;
+            break;
+        case hpf :
+            pDst[i] = hp;
+            break;
+        case bpf :
+            pDst[i] = bp;
+            break;
+        };
     }
 }
 
-
+    // Q can be [0.1,inf]
 void SVFilter::set_Q( float32_t Q )
 {
     if ( Q < 0.1f )
@@ -76,18 +92,19 @@
     this->Fs = new_Fs;
     this->update_parameters();
 }
-    
+
+    // fc is control frequency.
 void SVFilter::set_fc( int new_fc )                // Hz
 {
     this->fc = new_fc;
-    this->f = 2.0f * sin( 3.141592f * this->fc / this->Fs );
+    this->update_parameters();
 }
 
-
+    // fc * f_factor must be less then Fs/6
 void SVFilter::set_f_factor( float32_t new_f_factor )
 {
     this->f_factor = new_f_factor;
-    this->f = 2.0f * sin( 3.141592f * this->fc / this->Fs );
+    this->update_parameters();
 }
 
 void SVFilter::set_mode( svf_mode new_mode )