不韋 呂 / Mbed 2 deprecated F446_Spectrogram

Realtime sound spectrogram using FFT or linear prediction. Spectrogram is displayed on the display of PC. リアルタイム･スペクトログラム．解析の手法：FFT，線形予測法．スペクトログラムは PC のディスプレー装置に表示される．PC 側のプログラム：F446_Spectrogram.

Dependencies:   Array_Matrix mbed SerialTxRxIntr F446_AD_DA UIT_FFT_Real

MySpectrogram/Hamming.hpp

Committer:
MikamiUitOpen
Date:
2017-02-17
Revision:
0:a539141b9dec

File content as of revision 0:a539141b9dec:

//-------------------------------------------------------------------
//  Hamming windowing with zero-padding
//
//  2016/07/23, Copyright (c) 2016 MIKAMI, Naoki
//-------------------------------------------------------------------

#ifndef HAMMING_WINDOW_HPP
#define HAMMING_WINDOW_HPP

#include "mbed.h"
#include "Array.hpp"

namespace Mikami
{
    class HammingWindow
    {
    public:
        // Constructor
        HammingWindow(uint16_t nData, uint16_t nFft)
                : N_(nData), NFFT_(nFft), w_(nData)
        {
            float pi2L = 6.283185f/(float)nData;
            for (int k=0; k<nData; k++)
                w_[k] = 0.54f - 0.46f*cosf(k*pi2L);
        }
        
        // Destructor
        virtual ~HammingWindow() {}
        
        // Windowing
        void Execute(const float x[], float y[])
        {
            for (int n=0; n<N_; n++) y[n] = x[n]*w_[n];
            for (int n=N_; n<NFFT_; n++) y[n] = 0;
        }

    private:
        const int N_;
        const int NFFT_;
                
        Array<float> w_;

        // disallow copy constructor and assignment operator
        HammingWindow(const HammingWindow& );
        HammingWindow& operator=(const HammingWindow& );
    };
}
#endif  // HAMMING_WINDOW_HPP