不韋 呂 / Mbed 2 deprecated F446_DSP_FFT_Analyzer

FFT によるスペクトル解析器

Dependencies:   Array_Matrix mbed SerialTxRxIntr UIT_FFT_Real DSP_ADDA

MyFFT_Analyzer/FFT_Analyzer.cpp@0:91cc5a03f0ca, 2021-01-08 (annotated)

Committer:
MikamiUitOpen
Date:
Fri Jan 08 02:27:46 2021 +0000
Revision:
0:91cc5a03f0ca
1

Who changed what in which revision?

UserRevisionLine numberNew contents of line
MikamiUitOpen 0:91cc5a03f0ca 1 //-------------------------------------------------------
MikamiUitOpen 0:91cc5a03f0ca 2 // FFT を使ってスペクトル解析を行うクラス
MikamiUitOpen 0:91cc5a03f0ca 3 //
MikamiUitOpen 0:91cc5a03f0ca 4 // 2020/11/07, Copyright (c) 2020 MIKAMI, Naoki
MikamiUitOpen 0:91cc5a03f0ca 5 //-------------------------------------------------------
MikamiUitOpen 0:91cc5a03f0ca 6
MikamiUitOpen 0:91cc5a03f0ca 7 #include "FFT_Analyzer.hpp"
MikamiUitOpen 0:91cc5a03f0ca 8
MikamiUitOpen 0:91cc5a03f0ca 9 namespace Mikami
MikamiUitOpen 0:91cc5a03f0ca 10 {
MikamiUitOpen 0:91cc5a03f0ca 11 FftAnalyzer::FftAnalyzer(int nFft)
MikamiUitOpen 0:91cc5a03f0ca 12 : N_FFT_(nFft), fft_(nFft), wHm_(nFft, nFft),
MikamiUitOpen 0:91cc5a03f0ca 13 xData_(nFft), wData_(nFft), yFft_(nFft/2+1) {}
MikamiUitOpen 0:91cc5a03f0ca 14
MikamiUitOpen 0:91cc5a03f0ca 15 void FftAnalyzer::Execute(const Array<float> &xn, Array<float> &absFt)
MikamiUitOpen 0:91cc5a03f0ca 16 {
MikamiUitOpen 0:91cc5a03f0ca 17 xData_ = xn; // データを作業領域にコピー
MikamiUitOpen 0:91cc5a03f0ca 18
MikamiUitOpen 0:91cc5a03f0ca 19 // 直流分を除去
MikamiUitOpen 0:91cc5a03f0ca 20 float sum = 0;
MikamiUitOpen 0:91cc5a03f0ca 21 for (int n=0; n<N_FFT_; n++) sum = sum + xData_[n];
MikamiUitOpen 0:91cc5a03f0ca 22 float ave = sum/N_FFT_;
MikamiUitOpen 0:91cc5a03f0ca 23 for (int n=0; n<N_FFT_; n++) xData_[n] = xData_[n] - ave;
MikamiUitOpen 0:91cc5a03f0ca 24
MikamiUitOpen 0:91cc5a03f0ca 25 wHm_.Execute(xData_, wData_); // 窓掛け
MikamiUitOpen 0:91cc5a03f0ca 26
MikamiUitOpen 0:91cc5a03f0ca 27 fft_.Execute(wData_, yFft_); // FFT の実行
MikamiUitOpen 0:91cc5a03f0ca 28
MikamiUitOpen 0:91cc5a03f0ca 29 for (int n=0; n<=N_FFT_/2; n++) // 絶対値に変換
MikamiUitOpen 0:91cc5a03f0ca 30 absFt[n] = 100.0f*abs(yFft_[n]);
MikamiUitOpen 0:91cc5a03f0ca 31 }
MikamiUitOpen 0:91cc5a03f0ca 32 }