CQpub0 Mikami
The experiment using this program is introduced on "Interface" No.2, CQ publishing Co.,Ltd, 2015. 本プログラムを使った実験は，CQ出版社のインターフェース 2015年2月号で紹介しています．
Dependencies: DSProcessingIO mbed
Diff: Biquad.hpp
- Revision:
- 0:398107c96b1b
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/Biquad.hpp Tue Jul 15 08:58:36 2014 +0000
@@ -0,0 +1,45 @@
+//--------------------------------------------------------------
+// Biquad filter for IIR filter of cascade structure
+// Copyright (c) 2014 MIKAMI, Naoki, 2014/07/15
+//--------------------------------------------------------------
+
+#ifndef IIR_BIQUAD_HPP
+#define IIR_BIQUAD_HPP
+
+#include "mbed.h"
+
+namespace Mikami
+{
+ // 2nd order IIR filter
+ class Biquad
+ {
+ public:
+ struct Coefs { float a1, a2, b1, b2; };
+
+ Biquad() {} // Default constructore
+
+ Biquad(const Coefs ck)
+ : a1_(ck.a1), a2_(ck.a2), b1_(ck.b1), b2_(ck.b2)
+ { Clear(); }
+
+ float Execute(float xn)
+ {
+ float un = xn + a1_*un1_ + a2_*un2_;
+ float yn = un + b1_*un1_ + b2_*un2_;
+
+ un2_ = un1_;
+ un1_ = un;
+
+ return yn;
+ }
+
+ void Clear() { un1_ = un2_ = 0; }
+
+ private:
+ float a1_, a2_, b1_, b2_;
+ float un1_, un2_;
+
+ Biquad(const Biquad&);
+ };
+}
+#endif // IIR_BIQUAD_HPP