Diff: BiQuad4.h

Revision:

0:caa20b96f300

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/BiQuad4.h	Mon Oct 22 09:11:21 2018 +0000
@@ -0,0 +1,53 @@
+#ifndef BIQUAD4_BIQUAD4_H
+#define BIQUAD4_BIQUAD4_H
+
+#include <vector>
+#include <complex>
+
+/** BiQuad class implements a single filter
+ *
+ * Filters that - in the z domain - are the ratio of two fourth order functions. The general form is:
+ *
+ *        b0 + b1 z^-1 + b2 z^-2 + b3 z^-3 + b4 z^-4
+ * H(z) = ------------------------------------------
+ *        a0 + a1 z^-1 + a2 z^-2 + a3 z^-3 + a4 z^-4
+ * Which is often normalized by dividing all coefficients by a0.
+ */
+class BiQuad4 {
+
+private:
+
+    double B[5];
+    double A[4];
+    double wz[4];
+    
+    bool resetStateOnGainChange;
+
+  /**
+     * Sets the gain parameters
+     */
+    void set( double b0, double b1, double b2, double b3, double b4, double a1, double a2, double a3, double a4 );
+
+public:
+
+    /**
+     * Initialize a unity TF biquad
+     * @return BiQuad instance
+     */
+    BiQuad4( );
+
+    // Initialize a normalized biquad filter
+     
+    BiQuad4( double b0, double b1, double b2, double b3, double b4, double a1, double a2, double a3, double a4 );
+
+    /**
+     * Execute one digital timestep and return the result...
+     * @param x input of the filer
+     * @return output of the filter
+     */
+    double step( double x );
+
+    void setResetStateOnGainChange( bool v );
+};
+
+#endif //BIQUAD_BIQUAD_H