Diff: biquad.h

Revision:

0:f8ed62dbacbc

Child:

1:9c0546cd518e

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/biquad.h	Tue Feb 14 19:12:33 2012 +0000
@@ -0,0 +1,53 @@
+/*
+ *  biquad.cpp
+ *
+ *  Original source material from Robert Bristow Johnson at 
+ *  http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt
+ *  
+ *  Derived from public domain C implementation by Tom St. Denis
+ *
+ *  Thanks gents!
+ *
+ *  C++-ification by Mark J. Howell
+ *
+ */
+
+#include <math.h>
+
+#ifndef M_LN2
+#define M_LN2       0.69314718055994530942
+#endif
+
+#ifndef M_PI
+#define M_PI        3.14159265358979323846
+#endif
+
+/* filter types */
+typedef enum {
+    LPF, /* low pass filter */
+    HPF, /* High pass filter */
+    BPF, /* band pass filter */
+    NOTCH, /* Notch Filter */
+    PEQ, /* Peaking band EQ filter */
+    LSH, /* Low shelf filter */
+    HSH /* High shelf filter */
+} BIQUAD_FILTER_TYPE;
+
+template <typename T>
+class Biquad {
+
+public:
+    Biquad(BIQUAD_FILTER_TYPE type, 
+        T dbGain,  /* gain of filter */
+        T freq,  /* center frequency */
+        T srate,  /* sampling rate */
+        T bandwidth); /* bandwidth in octaves */
+        
+    void Reset(BIQUAD_FILTER_TYPE type, T dbGain, T freq, T srate, T bandwidth);
+    
+    T Calculate(T sample);
+    
+    T a0, a1, a2, a3, a4;
+    T x1, x2, y1, y2;
+
+};