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/FFT_Analyzer.cpp

Committer:
MikamiUitOpen
Date:
2018-11-04
Revision:
6:c38ec7939609
Parent:
0:a539141b9dec
Child:
7:5ba884060d3b

File content as of revision 6:c38ec7939609:

//-------------------------------------------------------
//  Class for spectrum analysis using FFT
//
//  2018/11/04, Copyright (c) 2018 MIKAMI, Naoki
//-------------------------------------------------------

#include "FFT_Analyzer.hpp"

namespace Mikami
{
    FftAnalyzer::FftAnalyzer(int nData, int nFft)
        : AnalyzerBase(nData, nFft, nFft),
          yFft_(nFft/2+1) {}

    void FftAnalyzer::Analyze(const float xn[], float yn[])
    {
        fft_.Execute(xn, yFft_);    // Execute FFT
        
        // Translate to dB
        for (int n=2; n<=N_FFT_/2; n++)
            yn[n] = 10.0f*log10f(Norm(yFft_[n]));
    }
}