Diff: MyClasses_Functions/IIR_CascadeFrqResp.hpp

Revision:

0:04b43b777fae

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MyClasses_Functions/IIR_CascadeFrqResp.hpp	Tue Apr 19 09:46:11 2016 +0000
@@ -0,0 +1,48 @@
+//-----------------------------------------------------------
+//  Frequency response for IIR filter of cascade form
+//
+//  2016/04/16, Copyright (c) 2016 MIKAMI, Naoki
+//-----------------------------------------------------------
+
+#ifndef IIR_CASCADE_FREQUENCY_RESPONSE_HPP
+#define IIR_CASCADE_FREQUENCY_RESPONSE_HPP
+
+#include "FrequancyResponseBase.hpp"
+#include "Biquad.hpp"
+
+namespace Mikami
+{
+    class IIR_CascadeFrqResp : public FrequencyResponse
+    {
+    public:
+        IIR_CascadeFrqResp() {}
+
+        // 次数とフィルタの係数設定
+        void SetParams(int order, float g0, Biquad::Coefs ck[])
+        {
+            order_ = order;
+            g0_ = g0;
+            ck_ = ck;
+        }
+
+        // 周波数応答の絶対値を返す関数, 引数: z^(-1)
+        virtual float AbsH_z(Complex u)
+        {
+            Complex h = g0_;
+            for (int k=0; k<order_/2; k++)
+            h = h*(1.0f + (ck_[k].b1 + ck_[k].b2*u)*u)
+                /((1.0f - (ck_[k].a1 + ck_[k].a2*u)*u));
+            return abs(h);       
+        }
+        
+    private:
+        int order_;
+        float g0_;
+        Biquad::Coefs *ck_;
+
+        // disallow copy constructor and assignment operator
+        IIR_CascadeFrqResp(const IIR_CascadeFrqResp&);
+        IIR_CascadeFrqResp& operator=(const IIR_CascadeFrqResp&);
+    };
+}
+#endif  // IIR_CASCADE_FREQUENCY_RESPONSE_HPP
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