WindowingDesignLH.hpp

00001 //------------------------------------------------------------------------------
00002 //  Design of FIR filter of LPF and HPF using window method -- Header
00003 //
00004 //  2014/11/09, Copyright (c) 2014 MIKAMI, Naoki
00005 //------------------------------------------------------------------------------
00006 
00007 #ifndef HAMMING_WINDOWING_DESIGN_HPP
00008 #define HAMMING_WINDOWING_DESIGN_HPP
00009 
00010 #include "mbed.h"
00011 
00012 namespace Mikami
00013 {
00014     class WindowingDesign
00015     {
00016     public:
00017         struct Coefs { float a1, a2, b1; };
00018         enum Type { LPF, HPF };
00019 
00020         // Constructor
00021         WindowingDesign(int order, float fs);
00022 
00023         //Destructor
00024         ~WindowingDesign()
00025         {
00026             delete[] hm_;
00027             delete[] wn_;
00028         }
00029 
00030         // Execution of design
00031         void Design(int order, Type pb, float fc, float hk[]);
00032 
00033     private:
00034         static const float PI_ = 3.1415926536f;
00035         const float FS_;    // Sampling frequency
00036         const float PI_FS_;
00037         
00038         float *hm_;     // For coefficients
00039         float *wn_;     // For Windwo
00040                 
00041         int order_;     // Order
00042         float fC_;      // Cutoff frequency
00043         
00044         // Calculation of coefficients for LPF
00045         void LpfCoefficients();
00046         // Transform LPF to HPF
00047         void ToHpf();
00048         // Hamming window
00049         void HammWindow();
00050     };
00051 }
00052 #endif  // HAMMING_WINDOWING_DESIGN_HPP