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

Biquad.hpp@0:a9412b9e85b7, 2014-10-23 (annotated)

Committer:
MikamiUitOpen
Date:
Thu Oct 23 06:44:40 2014 +0000
Revision:
0:a9412b9e85b7
1

Who changed what in which revision?

UserRevisionLine numberNew contents of line
MikamiUitOpen 0:a9412b9e85b7 1 //--------------------------------------------------------------
MikamiUitOpen 0:a9412b9e85b7 2 // Biquad filter for IIR filter of cascade structure
MikamiUitOpen 0:a9412b9e85b7 3 // 2014/10/21, Copyright (c) 2014 MIKAMI, Naoki
MikamiUitOpen 0:a9412b9e85b7 4 //--------------------------------------------------------------
MikamiUitOpen 0:a9412b9e85b7 5
MikamiUitOpen 0:a9412b9e85b7 6 #ifndef IIR_BIQUAD_HPP
MikamiUitOpen 0:a9412b9e85b7 7 #define IIR_BIQUAD_HPP
MikamiUitOpen 0:a9412b9e85b7 8
MikamiUitOpen 0:a9412b9e85b7 9 #include "mbed.h"
MikamiUitOpen 0:a9412b9e85b7 10
MikamiUitOpen 0:a9412b9e85b7 11 // 2nd order IIR filter
MikamiUitOpen 0:a9412b9e85b7 12 class Biquad
MikamiUitOpen 0:a9412b9e85b7 13 {
MikamiUitOpen 0:a9412b9e85b7 14 public:
MikamiUitOpen 0:a9412b9e85b7 15 struct Coefs { float a1, a2, b1, b2; };
MikamiUitOpen 0:a9412b9e85b7 16
MikamiUitOpen 0:a9412b9e85b7 17 Biquad() {} // Default constructore
MikamiUitOpen 0:a9412b9e85b7 18
MikamiUitOpen 0:a9412b9e85b7 19 Biquad(const Coefs ck)
MikamiUitOpen 0:a9412b9e85b7 20 : a1_(ck.a1), a2_(ck.a2), b1_(ck.b1), b2_(ck.b2)
MikamiUitOpen 0:a9412b9e85b7 21 { Clear(); }
MikamiUitOpen 0:a9412b9e85b7 22
MikamiUitOpen 0:a9412b9e85b7 23 float Execute(float xn)
MikamiUitOpen 0:a9412b9e85b7 24 {
MikamiUitOpen 0:a9412b9e85b7 25 float un = xn + a1_*un1_ + a2_*un2_;
MikamiUitOpen 0:a9412b9e85b7 26 float yn = un + b1_*un1_ + b2_*un2_;
MikamiUitOpen 0:a9412b9e85b7 27
MikamiUitOpen 0:a9412b9e85b7 28 un2_ = un1_;
MikamiUitOpen 0:a9412b9e85b7 29 un1_ = un;
MikamiUitOpen 0:a9412b9e85b7 30
MikamiUitOpen 0:a9412b9e85b7 31 return yn;
MikamiUitOpen 0:a9412b9e85b7 32 }
MikamiUitOpen 0:a9412b9e85b7 33
MikamiUitOpen 0:a9412b9e85b7 34 void Clear() { un1_ = un2_ = 0; }
MikamiUitOpen 0:a9412b9e85b7 35
MikamiUitOpen 0:a9412b9e85b7 36 private:
MikamiUitOpen 0:a9412b9e85b7 37 float a1_, a2_, b1_, b2_;
MikamiUitOpen 0:a9412b9e85b7 38 float un1_, un2_;
MikamiUitOpen 0:a9412b9e85b7 39
MikamiUitOpen 0:a9412b9e85b7 40 Biquad(const Biquad&);
MikamiUitOpen 0:a9412b9e85b7 41 };
MikamiUitOpen 0:a9412b9e85b7 42
MikamiUitOpen 0:a9412b9e85b7 43 #endif // IIR_BIQUAD_HPP
MikamiUitOpen 0:a9412b9e85b7 44