Hamming.hpp

00001 //-------------------------------------------------------------------
00002 //  Hamming windowing with zero-padding
00003 //
00004 //  2017/04/10, Copyright (c) 2017 MIKAMI, Naoki
00005 //-------------------------------------------------------------------
00006 
00007 #ifndef HAMMING_WINDOW_HPP
00008 #define HAMMING_WINDOW_HPP
00009 
00010 #include "mbed.h"
00011 #include "Array.hpp"
00012 
00013 namespace Mikami
00014 {
00015     class HammingWindow
00016     {
00017     public:
00018         // Constructor
00019         HammingWindow(uint16_t nData, uint16_t nFft)
00020                 : N_(nData), NFFT_(nFft), w_(nData)
00021         {
00022             float pi2L = 6.283185f/(float)nData;
00023             for (int k=0; k<nData; k++)
00024                 w_[k] = 0.54f - 0.46f*cosf(k*pi2L);
00025         }
00026 
00027         // Windowing
00028         void Execute(const float x[], float y[])
00029         {
00030             for (int n=0; n<N_; n++) y[n] = x[n]*w_[n];
00031             for (int n=N_; n<NFFT_; n++) y[n] = 0;
00032         }
00033 
00034     private:
00035         const int N_;
00036         const int NFFT_;
00037 
00038         Array<float> w_;
00039 
00040         // disallow copy constructor and assignment operator
00041         HammingWindow(const HammingWindow& );
00042         HammingWindow& operator=(const HammingWindow& );
00043     };
00044 }
00045 #endif  // HAMMING_WINDOW_HPP