不韋 呂 / Mbed 2 deprecated OpenCampus_FreqConv

入力信号のすべての周波数成分の周波数を，一定の周波数だけシフトするプログラム Frequeency shifter.

Dependencies:   mbed

FrequencyConverter/Biquad.hpp@2:b83deff26f1f, 2015-08-09 (annotated)

Committer:
MikamiUitOpen
Date:
Sun Aug 09 00:51:29 2015 +0000
Revision:
2:b83deff26f1f
Parent:
0:f69d3c64978d 
3

Who changed what in which revision?

UserRevisionLine numberNew contents of line
MikamiUitOpen 0:f69d3c64978d 1 //--------------------------------------------------------------
MikamiUitOpen 0:f69d3c64978d 2 // Biquad filter for IIR filter of cascade structure
MikamiUitOpen 0:f69d3c64978d 3 // Copyright (c) 2014 MIKAMI, Naoki, 2014/07/15
MikamiUitOpen 0:f69d3c64978d 4 //--------------------------------------------------------------
MikamiUitOpen 0:f69d3c64978d 5
MikamiUitOpen 0:f69d3c64978d 6 #ifndef IIR_BIQUAD_HPP
MikamiUitOpen 0:f69d3c64978d 7 #define IIR_BIQUAD_HPP
MikamiUitOpen 0:f69d3c64978d 8
MikamiUitOpen 0:f69d3c64978d 9 #include "mbed.h"
MikamiUitOpen 0:f69d3c64978d 10
MikamiUitOpen 0:f69d3c64978d 11 namespace Mikami
MikamiUitOpen 0:f69d3c64978d 12 {
MikamiUitOpen 0:f69d3c64978d 13 // 2nd order IIR filter
MikamiUitOpen 0:f69d3c64978d 14 class Biquad
MikamiUitOpen 0:f69d3c64978d 15 {
MikamiUitOpen 0:f69d3c64978d 16 public:
MikamiUitOpen 0:f69d3c64978d 17 struct Coefs { float a1, a2, b1, b2; };
MikamiUitOpen 0:f69d3c64978d 18
MikamiUitOpen 0:f69d3c64978d 19 Biquad() {} // Default constructore
MikamiUitOpen 0:f69d3c64978d 20
MikamiUitOpen 0:f69d3c64978d 21 Biquad(const Coefs ck)
MikamiUitOpen 0:f69d3c64978d 22 : a1_(ck.a1), a2_(ck.a2), b1_(ck.b1), b2_(ck.b2)
MikamiUitOpen 0:f69d3c64978d 23 { Clear(); }
MikamiUitOpen 0:f69d3c64978d 24
MikamiUitOpen 0:f69d3c64978d 25 float Execute(float xn)
MikamiUitOpen 0:f69d3c64978d 26 {
MikamiUitOpen 0:f69d3c64978d 27 float un = xn + a1_*un1_ + a2_*un2_;
MikamiUitOpen 0:f69d3c64978d 28 float yn = un + b1_*un1_ + b2_*un2_;
MikamiUitOpen 0:f69d3c64978d 29
MikamiUitOpen 0:f69d3c64978d 30 un2_ = un1_;
MikamiUitOpen 0:f69d3c64978d 31 un1_ = un;
MikamiUitOpen 0:f69d3c64978d 32
MikamiUitOpen 0:f69d3c64978d 33 return yn;
MikamiUitOpen 0:f69d3c64978d 34 }
MikamiUitOpen 0:f69d3c64978d 35
MikamiUitOpen 0:f69d3c64978d 36 void Clear() { un1_ = un2_ = 0; }
MikamiUitOpen 0:f69d3c64978d 37
MikamiUitOpen 0:f69d3c64978d 38 private:
MikamiUitOpen 0:f69d3c64978d 39 float a1_, a2_, b1_, b2_;
MikamiUitOpen 0:f69d3c64978d 40 float un1_, un2_;
MikamiUitOpen 0:f69d3c64978d 41
MikamiUitOpen 0:f69d3c64978d 42 Biquad(const Biquad&);
MikamiUitOpen 0:f69d3c64978d 43 };
MikamiUitOpen 0:f69d3c64978d 44 }
MikamiUitOpen 0:f69d3c64978d 45 #endif // IIR_BIQUAD_HPP