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/LPC_Analysis.cpp@18:6630d61aeb3c, 2016-02-22 (annotated)

Committer:
MikamiUitOpen
Date:
Mon Feb 22 13:54:51 2016 +0000
Revision:
18:6630d61aeb3c
Parent:
4:99d4d5ea06a2 
19

Who changed what in which revision?

UserRevisionLine numberNew contents of line
MikamiUitOpen 0:5c237fdcba23 1 //-------------------------------------------------------
MikamiUitOpen 0:5c237fdcba23 2 // Class for spectrum analysis using linear prediction
MikamiUitOpen 0:5c237fdcba23 3 //
MikamiUitOpen 4:99d4d5ea06a2 4 // 2015/12/15, Copyright (c) 2015 MIKAMI, Naoki
MikamiUitOpen 0:5c237fdcba23 5 //-------------------------------------------------------
MikamiUitOpen 0:5c237fdcba23 6
MikamiUitOpen 0:5c237fdcba23 7 #include "LPC_Analysis.hpp"
MikamiUitOpen 0:5c237fdcba23 8
MikamiUitOpen 0:5c237fdcba23 9 namespace Mikami
MikamiUitOpen 0:5c237fdcba23 10 {
MikamiUitOpen 0:5c237fdcba23 11 LpcAnalyzer::LpcAnalyzer(int nData, int nFft, int order)
MikamiUitOpen 3:7c26b701f363 12 : AnalyzerBase(nData, nFft, nData-1), ORDER_(order),
MikamiUitOpen 4:99d4d5ea06a2 13 lp_(nData-1, order), an_(new float[order]),
MikamiUitOpen 0:5c237fdcba23 14 xFft_(new float[nFft]), yFft_(new Complex[nFft/2+1]) {}
MikamiUitOpen 0:5c237fdcba23 15
MikamiUitOpen 0:5c237fdcba23 16 LpcAnalyzer::~LpcAnalyzer()
MikamiUitOpen 0:5c237fdcba23 17 {
MikamiUitOpen 0:5c237fdcba23 18 delete[] an_;
MikamiUitOpen 0:5c237fdcba23 19 delete[] xFft_;
MikamiUitOpen 0:5c237fdcba23 20 delete[] yFft_;
MikamiUitOpen 0:5c237fdcba23 21 }
MikamiUitOpen 0:5c237fdcba23 22
MikamiUitOpen 0:5c237fdcba23 23 void LpcAnalyzer::Analyze(const float xn[], float yn[])
MikamiUitOpen 0:5c237fdcba23 24 {
MikamiUitOpen 0:5c237fdcba23 25 float em;
MikamiUitOpen 4:99d4d5ea06a2 26 lp_.Execute(xn, an_, em);
MikamiUitOpen 0:5c237fdcba23 27
MikamiUitOpen 0:5c237fdcba23 28 // To spectrum
MikamiUitOpen 0:5c237fdcba23 29 xFft_[0] = 1.0f;
MikamiUitOpen 0:5c237fdcba23 30 for (int n=0; n<ORDER_; n++) xFft_[n+1] = -an_[n];
MikamiUitOpen 0:5c237fdcba23 31 for (int n=ORDER_+1; n<N_FFT_; n++) xFft_[n] = 0.0f;
MikamiUitOpen 0:5c237fdcba23 32 fft_.Execute(xFft_, yFft_); // execute FFT
MikamiUitOpen 0:5c237fdcba23 33
MikamiUitOpen 0:5c237fdcba23 34 // Translate to dB
MikamiUitOpen 0:5c237fdcba23 35 for (int n=0; n<=N_FFT_/2; n++)
MikamiUitOpen 0:5c237fdcba23 36 yn[n] = 10.0f*log10f(em/Norm(yFft_[n]));
MikamiUitOpen 0:5c237fdcba23 37 }
MikamiUitOpen 0:5c237fdcba23 38 }