Kenji Arai / Mbed OS CW_Decoder_using_FFT_on_F446

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Dependencies:   Array_Matrix F446_AD_DA ST7565_SPI_LCD TextLCD UIT_FFT_Real

Fork of F446_MySoundMachine by 不韋 呂

SignalProcessing/BilinearDesignLH.hpp@0:fa74b1130cc3, 2017-01-29 (annotated)

Committer:
MikamiUitOpen
Date:
Sun Jan 29 09:11:30 2017 +0000
Revision:
0:fa74b1130cc3
1

Who changed what in which revision?

UserRevisionLine numberNew contents of line
MikamiUitOpen 0:fa74b1130cc3 1 //------------------------------------------------------------------------
MikamiUitOpen 0:fa74b1130cc3 2 // Design of Butterworth LPF and HPF using bilinear transform -- Header
MikamiUitOpen 0:fa74b1130cc3 3 //
MikamiUitOpen 0:fa74b1130cc3 4 // 2016/03/31, Copyright (c) 2016 MIKAMI, Naoki
MikamiUitOpen 0:fa74b1130cc3 5 //------------------------------------------------------------------------
MikamiUitOpen 0:fa74b1130cc3 6
MikamiUitOpen 0:fa74b1130cc3 7 #ifndef BILINEAR_BUTTERWORTH_HPP
MikamiUitOpen 0:fa74b1130cc3 8 #define BILINEAR_BUTTERWORTH_HPP
MikamiUitOpen 0:fa74b1130cc3 9
MikamiUitOpen 0:fa74b1130cc3 10 #include "mbed.h"
MikamiUitOpen 0:fa74b1130cc3 11 #include <complex> // requisite
MikamiUitOpen 0:fa74b1130cc3 12 #include "Array.hpp"
MikamiUitOpen 0:fa74b1130cc3 13
MikamiUitOpen 0:fa74b1130cc3 14 namespace Mikami
MikamiUitOpen 0:fa74b1130cc3 15 {
MikamiUitOpen 0:fa74b1130cc3 16 typedef complex<float> Complex; // define "Complex"
MikamiUitOpen 0:fa74b1130cc3 17
MikamiUitOpen 0:fa74b1130cc3 18 class BilinearDesign
MikamiUitOpen 0:fa74b1130cc3 19 {
MikamiUitOpen 0:fa74b1130cc3 20 public:
MikamiUitOpen 0:fa74b1130cc3 21 struct Coefs { float a1, a2, b1, b2; };
MikamiUitOpen 0:fa74b1130cc3 22 enum Type { LPF, HPF };
MikamiUitOpen 0:fa74b1130cc3 23
MikamiUitOpen 0:fa74b1130cc3 24 // Constructor
MikamiUitOpen 0:fa74b1130cc3 25 BilinearDesign(int order, float fs)
MikamiUitOpen 0:fa74b1130cc3 26 : PI_FS_(PI_/fs), ORDER_(order),
MikamiUitOpen 0:fa74b1130cc3 27 sP_(order/2), zP_(order/2), ck_(order/2) {}
MikamiUitOpen 0:fa74b1130cc3 28
MikamiUitOpen 0:fa74b1130cc3 29 // Destractor
MikamiUitOpen 0:fa74b1130cc3 30 virtual ~BilinearDesign() {}
MikamiUitOpen 0:fa74b1130cc3 31
MikamiUitOpen 0:fa74b1130cc3 32 // Execution of design
MikamiUitOpen 0:fa74b1130cc3 33 void Execute(float fc, Type pb, Coefs c[], float& g);
MikamiUitOpen 0:fa74b1130cc3 34
MikamiUitOpen 0:fa74b1130cc3 35 private:
MikamiUitOpen 0:fa74b1130cc3 36 static const float PI_ = 3.1415926536f;
MikamiUitOpen 0:fa74b1130cc3 37 const float PI_FS_;
MikamiUitOpen 0:fa74b1130cc3 38 const int ORDER_;
MikamiUitOpen 0:fa74b1130cc3 39
MikamiUitOpen 0:fa74b1130cc3 40 Array<Complex> sP_; // Poles on s-plane
MikamiUitOpen 0:fa74b1130cc3 41 Array<Complex> zP_; // Poles on z-plane
MikamiUitOpen 0:fa74b1130cc3 42 Array<Coefs> ck_; // Coefficients of transfer function for cascade form
MikamiUitOpen 0:fa74b1130cc3 43
MikamiUitOpen 0:fa74b1130cc3 44 float gain_; // Gain factor for cascade form
MikamiUitOpen 0:fa74b1130cc3 45
MikamiUitOpen 0:fa74b1130cc3 46 void Butterworth();
MikamiUitOpen 0:fa74b1130cc3 47 void Bilinear(float fc);
MikamiUitOpen 0:fa74b1130cc3 48 void ToCascade(Type pb);
MikamiUitOpen 0:fa74b1130cc3 49 void GetGain(Type pb);
MikamiUitOpen 0:fa74b1130cc3 50 void GetCoefs(Coefs c[], float& gain);
MikamiUitOpen 0:fa74b1130cc3 51 };
MikamiUitOpen 0:fa74b1130cc3 52 }
MikamiUitOpen 0:fa74b1130cc3 53 #endif // BILINEAR_BUTTERWORTH_HPP