不韋 呂 / Mbed 2 deprecated F746_RealtimeSpectrumAnalyzer

Realtime spectrum analyzer. Using FFT, linear prediction, or cepstrum smoothing. Version using MEMS microphone and CODEC, named "F746_RealtimeSpectrumAnalyzer_MEMS_Mic" is registered. リアルタイム スペクトル解析器．解析の手法：FFT，線形予測法，ケプストラムによる平滑化の３種類．このプログラムの説明は，CQ出版社のインターフェース誌，2016年4月号に掲載．外付けのマイクまたは他の信号源等を A0 に接続する．線形予測法，ケプストラムは，スペクトル解析の対象を音声信号に想定してパラメータを設定している．MEMS マイクと CODEC を使ったバージョンを "F746_RealtimeSpectrumAnalyzer_MEMS_Mic" として登録．

Dependencies:   BSP_DISCO_F746NG BUTTON_GROUP LCD_DISCO_F746NG TS_DISCO_F746NG UIT_FFT_Real mbed

MyClasses/FFT_Analysis.cpp@2:095b360e0f54, 2015-12-13 (annotated)

Committer:
MikamiUitOpen
Date:
Sun Dec 13 07:20:14 2015 +0000
Revision:
2:095b360e0f54
Parent:
0:5c237fdcba23
Child:
3:7c26b701f363
3

Who changed what in which revision?

UserRevisionLine numberNew contents of line
MikamiUitOpen 0:5c237fdcba23 1 //-------------------------------------------------------
MikamiUitOpen 0:5c237fdcba23 2 // Class for spectrum analysis using FFT
MikamiUitOpen 0:5c237fdcba23 3 //
MikamiUitOpen 0:5c237fdcba23 4 // 2015/12/08, Copyright (c) 2015 MIKAMI, Naoki
MikamiUitOpen 0:5c237fdcba23 5 //-------------------------------------------------------
MikamiUitOpen 0:5c237fdcba23 6
MikamiUitOpen 0:5c237fdcba23 7 #include "FFT_Analysis.hpp"
MikamiUitOpen 0:5c237fdcba23 8
MikamiUitOpen 0:5c237fdcba23 9 namespace Mikami
MikamiUitOpen 0:5c237fdcba23 10 {
MikamiUitOpen 0:5c237fdcba23 11 FftAnalyzer::FftAnalyzer(int nData, int nFft)
MikamiUitOpen 0:5c237fdcba23 12 : AnalyzerBase(nData, nFft), wHm_(nData-1, nFft),
MikamiUitOpen 0:5c237fdcba23 13 xFft_(new float[nFft]),
MikamiUitOpen 0:5c237fdcba23 14 yFft_(new Complex[nFft/2+1]) {}
MikamiUitOpen 0:5c237fdcba23 15
MikamiUitOpen 0:5c237fdcba23 16 FftAnalyzer::~FftAnalyzer()
MikamiUitOpen 0:5c237fdcba23 17 {
MikamiUitOpen 0:5c237fdcba23 18 delete[] xFft_;
MikamiUitOpen 0:5c237fdcba23 19 delete[] yFft_;
MikamiUitOpen 0:5c237fdcba23 20 }
MikamiUitOpen 0:5c237fdcba23 21
MikamiUitOpen 0:5c237fdcba23 22 void FftAnalyzer::Analyze(const float xn[], float yn[])
MikamiUitOpen 0:5c237fdcba23 23 {
MikamiUitOpen 0:5c237fdcba23 24 wHm_.Execute(xn, xFft_); // Windowing and zero-padding
MikamiUitOpen 0:5c237fdcba23 25 fft_.Execute(xFft_, yFft_); // Execute FFT
MikamiUitOpen 0:5c237fdcba23 26
MikamiUitOpen 0:5c237fdcba23 27 // Translate to dB
MikamiUitOpen 0:5c237fdcba23 28 for (int n=0; n<=N_FFT_/2; n++)
MikamiUitOpen 0:5c237fdcba23 29 yn[n] = 10.0f*log10f(Norm(yFft_[n]));
MikamiUitOpen 0:5c237fdcba23 30 }
MikamiUitOpen 0:5c237fdcba23 31 }
MikamiUitOpen 2:095b360e0f54 32