FIR_FrqResp.hpp

00001 //-----------------------------------------------------------
00002 //  Frequency response for FIR filter of direct form
00003 //
00004 //  2016/04/17, Copyright (c) 2016 MIKAMI, Naoki
00005 //-----------------------------------------------------------
00006 
00007 #ifndef FIR_DIRECT_FREQUENCY_RESPONSE_HPP
00008 #define FIR_DIRECT_FREQUENCY_RESPONSE_HPP
00009 
00010 #include "FrequancyResponseBase.hpp"
00011 
00012 namespace Mikami
00013 {
00014     class FIR_FrqResp : public FrequencyResponse
00015     {
00016     public:
00017         FIR_FrqResp() : ORDER_(10)
00018         {
00019             float hk[] =
00020             {
00021                 -3.391730E-02f,  1.206756E-03f,  5.917430E-02f,  1.457397E-01f,
00022                  2.247430E-01f,  2.567399E-01f,  2.247430E-01f,  1.457397E-01f,
00023                  5.917430E-02f,  1.206756E-03f, -3.391730E-02f
00024             };
00025             h_ = new float[ORDER_+1];
00026             for (int k=0; k<=ORDER_; k++) h_[k] = hk[k];
00027         }
00028 
00029         // 周波数応答の絶対値を返す関数, 引数: z^(-1)
00030         virtual float AbsH_z(Complex u)
00031         {
00032             Complex h = 0;
00033             for (int k=ORDER_; k>=0; k--)
00034                 h = h*u + h_[k];
00035             return abs(h);       
00036         }
00037         
00038     private:
00039         const int ORDER_;
00040         float *h_;
00041     };
00042 }
00043 #endif  // FIR_DIRECT_FREQUENCY_RESPONSE_HPP
00044