不韋 呂 / Mbed 2 deprecated F746_RealtimeSpectrumAnalyzer_MEMS_Mic

Version using MEMS microphone and CODEC for the program "F746_RealtimeSpectrumAnalyzer". "F746_RealtimeSpectrumAnalyzer" の入力を MEMS のマイクと CODEC に変更．このプログラムは Tomona Nanase さんが作成し DISCO-F746NG_Oscilloscope の名前で登録しているプログラムで， CODEC を使って入力する部分を参考にして作成．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．

Dependencies:   BSP_DISCO_F746NG BUTTON_GROUP LCD_DISCO_F746NG TS_DISCO_F746NG UIT_FFT_Real mbed

MyClasses_Functions/LinearPrediction.cpp@8:e7dc8658c5cd, 2016-04-19 (annotated)

Committer:
MikamiUitOpen
Date:
Tue Apr 19 09:35:24 2016 +0000
Revision:
8:e7dc8658c5cd
Parent:
0:0e5131366580 
9

Who changed what in which revision?

UserRevisionLine numberNew contents of line
MikamiUitOpen 0:0e5131366580 1 //-----------------------------------------------------
MikamiUitOpen 0:0e5131366580 2 // Class for linear prediction
MikamiUitOpen 0:0e5131366580 3 //
MikamiUitOpen 0:0e5131366580 4 // 2015/12/08, Copyright (c) 2015 MIKAMI, Naoki
MikamiUitOpen 0:0e5131366580 5 //-----------------------------------------------------
MikamiUitOpen 0:0e5131366580 6
MikamiUitOpen 0:0e5131366580 7 #include "LinearPrediction.hpp"
MikamiUitOpen 0:0e5131366580 8
MikamiUitOpen 0:0e5131366580 9 namespace Mikami
MikamiUitOpen 0:0e5131366580 10 {
MikamiUitOpen 0:0e5131366580 11 LinearPred::LinearPred(int nData, int order)
MikamiUitOpen 0:0e5131366580 12 : N_DATA_(nData), ORDER_(order),
MikamiUitOpen 0:0e5131366580 13 r_(new float[order+1]), k_(new float[order]),
MikamiUitOpen 0:0e5131366580 14 am_(new float[order]) {}
MikamiUitOpen 0:0e5131366580 15
MikamiUitOpen 0:0e5131366580 16 LinearPred::~LinearPred()
MikamiUitOpen 0:0e5131366580 17 {
MikamiUitOpen 0:0e5131366580 18 delete[] r_;
MikamiUitOpen 0:0e5131366580 19 delete[] k_;
MikamiUitOpen 0:0e5131366580 20 delete[] am_;
MikamiUitOpen 0:0e5131366580 21 }
MikamiUitOpen 0:0e5131366580 22
MikamiUitOpen 0:0e5131366580 23 // Calculate linear-predictive coefficients
MikamiUitOpen 0:0e5131366580 24 bool LinearPred::Execute(const float x[], float a[],
MikamiUitOpen 0:0e5131366580 25 float &em)
MikamiUitOpen 0:0e5131366580 26 {
MikamiUitOpen 0:0e5131366580 27 AutoCorr(x);
MikamiUitOpen 0:0e5131366580 28 return Durbin(a, em);
MikamiUitOpen 0:0e5131366580 29 }
MikamiUitOpen 0:0e5131366580 30
MikamiUitOpen 0:0e5131366580 31 // Calculate auto-correlation
MikamiUitOpen 0:0e5131366580 32 void LinearPred::AutoCorr(const float x[])
MikamiUitOpen 0:0e5131366580 33 {
MikamiUitOpen 0:0e5131366580 34 for (int j=0; j<=ORDER_; j++)
MikamiUitOpen 0:0e5131366580 35 {
MikamiUitOpen 0:0e5131366580 36 r_[j] = 0.0;
MikamiUitOpen 0:0e5131366580 37 for (int n=0; n<N_DATA_-j; n++)
MikamiUitOpen 0:0e5131366580 38 r_[j] = r_[j] + x[n]*x[n+j];
MikamiUitOpen 0:0e5131366580 39 }
MikamiUitOpen 0:0e5131366580 40 }
MikamiUitOpen 0:0e5131366580 41
MikamiUitOpen 0:0e5131366580 42 // Levinson-Durbin algorithm
MikamiUitOpen 0:0e5131366580 43 bool LinearPred::Durbin(float a[], float &em)
MikamiUitOpen 0:0e5131366580 44 {
MikamiUitOpen 0:0e5131366580 45 // Initialization
MikamiUitOpen 0:0e5131366580 46 em = r_[0];
MikamiUitOpen 0:0e5131366580 47
MikamiUitOpen 0:0e5131366580 48 // Repeat
MikamiUitOpen 0:0e5131366580 49 for (int m=0; m<ORDER_; m++)
MikamiUitOpen 0:0e5131366580 50 {
MikamiUitOpen 0:0e5131366580 51 float w = r_[m+1];
MikamiUitOpen 0:0e5131366580 52 for (int j=0; j<=m-1; j++)
MikamiUitOpen 0:0e5131366580 53 w = w - r_[m-j]*a[j];
MikamiUitOpen 0:0e5131366580 54
MikamiUitOpen 0:0e5131366580 55 k_[m] = w/em;
MikamiUitOpen 0:0e5131366580 56 em = em*(1 - k_[m]*k_[m]);
MikamiUitOpen 0:0e5131366580 57
MikamiUitOpen 0:0e5131366580 58 if (em < 0) break; // Error for negative squared sum of residual
MikamiUitOpen 0:0e5131366580 59
MikamiUitOpen 0:0e5131366580 60 a[m] = k_[m];
MikamiUitOpen 0:0e5131366580 61 for (int j=0; j<=m-1; j++)
MikamiUitOpen 0:0e5131366580 62 am_[j] = a[j];
MikamiUitOpen 0:0e5131366580 63 for (int j=0; j<=m-1; j++)
MikamiUitOpen 0:0e5131366580 64 a[j] = am_[j] - k_[m]*am_[m-j-1];
MikamiUitOpen 0:0e5131366580 65 }
MikamiUitOpen 0:0e5131366580 66
MikamiUitOpen 0:0e5131366580 67 if (em < 0) return false;
MikamiUitOpen 0:0e5131366580 68 else return true;
MikamiUitOpen 0:0e5131366580 69 }
MikamiUitOpen 0:0e5131366580 70 }