不韋 呂 / Mbed 2 deprecated UIT2_VariableIIR_LPF

Cutoff frequency variable LPF by IIR 6th-order Butterworth filter for ST Nucleo F401RE.

Dependencies:   UIT_IIR_Filter UIT_ACM1602NI UITDSP_ADDA mbed UIT_AQM1602

BilinearDesignLpfHpf/BilinearDesignLH.hpp@5:b291c4653eb9, 2014-12-07 (annotated)

Committer:
MikamiUitOpen
Date:
Sun Dec 07 05:45:07 2014 +0000
Revision:
5:b291c4653eb9
Parent:
0:a9412b9e85b7 
6

Who changed what in which revision?

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MikamiUitOpen 0:a9412b9e85b7 1 //------------------------------------------------------------------------------
MikamiUitOpen 0:a9412b9e85b7 2 // Design of Butterworth LPF and HPF using bilinear transform -- Header
MikamiUitOpen 0:a9412b9e85b7 3 //
MikamiUitOpen 0:a9412b9e85b7 4 // 2014/06/29, Copyright (c) 2014 MIKAMI, Naoki
MikamiUitOpen 0:a9412b9e85b7 5 //------------------------------------------------------------------------------
MikamiUitOpen 0:a9412b9e85b7 6
MikamiUitOpen 0:a9412b9e85b7 7 #ifndef BILINEAR_BUTTERWORTH_HPP
MikamiUitOpen 0:a9412b9e85b7 8 #define BILINEAR_BUTTERWORTH_HPP
MikamiUitOpen 0:a9412b9e85b7 9
MikamiUitOpen 0:a9412b9e85b7 10 #include "mbed.h"
MikamiUitOpen 0:a9412b9e85b7 11 #include <complex> // requisite
MikamiUitOpen 0:a9412b9e85b7 12
MikamiUitOpen 0:a9412b9e85b7 13 namespace Mikami
MikamiUitOpen 0:a9412b9e85b7 14 {
MikamiUitOpen 0:a9412b9e85b7 15 typedef complex<float> Complex; // define "Complex"
MikamiUitOpen 0:a9412b9e85b7 16
MikamiUitOpen 5:b291c4653eb9 17 class BilinearDesign
MikamiUitOpen 0:a9412b9e85b7 18 {
MikamiUitOpen 0:a9412b9e85b7 19 public:
MikamiUitOpen 0:a9412b9e85b7 20 struct Coefs { float a1, a2, b1; };
MikamiUitOpen 0:a9412b9e85b7 21 enum Type { LPF, HPF };
MikamiUitOpen 0:a9412b9e85b7 22
MikamiUitOpen 0:a9412b9e85b7 23 // Constructor
MikamiUitOpen 5:b291c4653eb9 24 BilinearDesign(int order, float fs, Type pb)
MikamiUitOpen 0:a9412b9e85b7 25 : PI_FS_(PI_/fs), ORDER_(order), PB_(pb)
MikamiUitOpen 0:a9412b9e85b7 26 {
MikamiUitOpen 0:a9412b9e85b7 27 sP_ = new Complex[order/2];
MikamiUitOpen 0:a9412b9e85b7 28 zP_ = new Complex[order/2];
MikamiUitOpen 0:a9412b9e85b7 29 ck_ = new Coefs[order/2];
MikamiUitOpen 0:a9412b9e85b7 30 }
MikamiUitOpen 0:a9412b9e85b7 31
MikamiUitOpen 0:a9412b9e85b7 32 // Destractor
MikamiUitOpen 5:b291c4653eb9 33 ~BilinearDesign()
MikamiUitOpen 0:a9412b9e85b7 34 {
MikamiUitOpen 0:a9412b9e85b7 35 delete[] sP_;
MikamiUitOpen 0:a9412b9e85b7 36 delete[] zP_;
MikamiUitOpen 0:a9412b9e85b7 37 delete[] ck_;
MikamiUitOpen 0:a9412b9e85b7 38 }
MikamiUitOpen 0:a9412b9e85b7 39
MikamiUitOpen 0:a9412b9e85b7 40 // Execution of design
MikamiUitOpen 0:a9412b9e85b7 41 void Execute(float fc, Coefs c[], float& g);
MikamiUitOpen 0:a9412b9e85b7 42
MikamiUitOpen 0:a9412b9e85b7 43 private:
MikamiUitOpen 0:a9412b9e85b7 44 static const float PI_ = 3.1415926536f;
MikamiUitOpen 0:a9412b9e85b7 45 const float PI_FS_;
MikamiUitOpen 0:a9412b9e85b7 46 const int ORDER_;
MikamiUitOpen 0:a9412b9e85b7 47 const Type PB_;
MikamiUitOpen 0:a9412b9e85b7 48
MikamiUitOpen 0:a9412b9e85b7 49 Complex* sP_; // Poles on s-plane
MikamiUitOpen 0:a9412b9e85b7 50 Complex* zP_; // Poles on z-plane
MikamiUitOpen 0:a9412b9e85b7 51 Coefs* ck_; // Coefficients of transfer function for cascade form
MikamiUitOpen 0:a9412b9e85b7 52 float gain_; // Gain factor for cascade form
MikamiUitOpen 0:a9412b9e85b7 53
MikamiUitOpen 0:a9412b9e85b7 54 void Butterworth();
MikamiUitOpen 0:a9412b9e85b7 55 void Bilinear(float fc);
MikamiUitOpen 0:a9412b9e85b7 56 void ToCascade();
MikamiUitOpen 0:a9412b9e85b7 57 void GetGain();
MikamiUitOpen 0:a9412b9e85b7 58 void GetCoefs(Coefs c[], float& gain);
MikamiUitOpen 0:a9412b9e85b7 59 };
MikamiUitOpen 0:a9412b9e85b7 60 }
MikamiUitOpen 0:a9412b9e85b7 61 #endif // BILINEAR_BUTTERWORTH_HPP
MikamiUitOpen 0:a9412b9e85b7 62