不韋 呂 / Mbed 2 deprecated UIT2_IIR_Cascade

IIR filter of cascade form using float type operations and coefficients for ST Nucleo F401RE.

Dependencies:   UIT_ADDA mbed

main.cpp@4:83e5419d22bb, 2014-10-23 (annotated)

Committer:
MikamiUitOpen
Date:
Thu Oct 23 00:25:44 2014 +0000
Revision:
4:83e5419d22bb
Parent:
2:d4999d914eee
Child:
6:9b78c8c6ed27
5

Who changed what in which revision?

UserRevisionLine numberNew contents of line
MikamiUitOpen 0:8c15b3d0523e 1 //--------------------------------------------------------------
MikamiUitOpen 2:d4999d914eee 2 // IIR フィルタ，縦続形，float で演算
MikamiUitOpen 0:8c15b3d0523e 3 // Analog Input : A0
MikamiUitOpen 0:8c15b3d0523e 4 // Analog Output: MCP4922 using SPI
MikamiUitOpen 4:83e5419d22bb 5 // 2014/10/23, Copyright (c) 2014 MIKAMI, Naoki
MikamiUitOpen 0:8c15b3d0523e 6 //--------------------------------------------------------------
MikamiUitOpen 0:8c15b3d0523e 7
MikamiUitOpen 0:8c15b3d0523e 8 #include "mbed.h"
MikamiUitOpen 0:8c15b3d0523e 9
MikamiUitOpen 2:d4999d914eee 10 #include "ADC_Base.hpp" // for ADC not using interrupt
MikamiUitOpen 0:8c15b3d0523e 11 #include "DAC_MCP4922.hpp" // for DAC MCP4922
MikamiUitOpen 0:8c15b3d0523e 12 #include "ScfClockTim3.hpp" // for clock supplied to SCF
MikamiUitOpen 0:8c15b3d0523e 13
MikamiUitOpen 0:8c15b3d0523e 14 using namespace Mikami;
MikamiUitOpen 0:8c15b3d0523e 15
MikamiUitOpen 0:8c15b3d0523e 16 const int ORDER_ = 6; // order
MikamiUitOpen 0:8c15b3d0523e 17 struct Un { float u1, u2; };
MikamiUitOpen 0:8c15b3d0523e 18 struct Coefs { float a1, a2, b1, b2; };
MikamiUitOpen 0:8c15b3d0523e 19
MikamiUitOpen 0:8c15b3d0523e 20 // 低域通過フィルタ
MikamiUitOpen 0:8c15b3d0523e 21 // 連立チェビシェフ特性
MikamiUitOpen 0:8c15b3d0523e 22 // 次数　　　　：6 次
MikamiUitOpen 0:8c15b3d0523e 23 // 標本化周波数： 12.00 kHz
MikamiUitOpen 0:8c15b3d0523e 24 // 遮断周波数　： 0.40 kHz
MikamiUitOpen 0:8c15b3d0523e 25 // 通過域のリップル： 0.50 dB
MikamiUitOpen 0:8c15b3d0523e 26 // 阻止域の減衰量　：40.00 dB
MikamiUitOpen 0:8c15b3d0523e 27 const Coefs ck_[ORDER_/2] = {
MikamiUitOpen 0:8c15b3d0523e 28 { 1.837790E+00f, -8.507293E-01f, -1.603320E+00f, 1.000000E+00f}, // 1段目
MikamiUitOpen 0:8c15b3d0523e 29 { 1.904445E+00f, -9.382561E-01f, -1.919647E+00f, 1.000000E+00f}, // 2段目
MikamiUitOpen 0:8c15b3d0523e 30 { 1.942552E+00f, -9.865720E-01f, -1.942961E+00f, 1.000000E+00f}}; // 3段目
MikamiUitOpen 0:8c15b3d0523e 31 const float g0_ = 1.000028E-02f; // 利得定数
MikamiUitOpen 0:8c15b3d0523e 32
MikamiUitOpen 4:83e5419d22bb 33 const int FS_ = 12000; // Sampling frequency: 12 kHz
MikamiUitOpen 4:83e5419d22bb 34 ADC_Base adc_(A0, FS_); // for AD
MikamiUitOpen 4:83e5419d22bb 35 DAC_MCP4922 myDac_; // for DA
MikamiUitOpen 0:8c15b3d0523e 36
MikamiUitOpen 0:8c15b3d0523e 37 int main()
MikamiUitOpen 0:8c15b3d0523e 38 {
MikamiUitOpen 0:8c15b3d0523e 39 ScfClockTim3(500000); // cutoff frequency: 5 kHz
MikamiUitOpen 0:8c15b3d0523e 40
MikamiUitOpen 1:b688b41d0ba1 41 Un uk[ORDER_/2]; // 過去の計算結果を格納する配列
MikamiUitOpen 0:8c15b3d0523e 42 // 過去の入力信号が格納される配列をクリア
MikamiUitOpen 0:8c15b3d0523e 43 for (int k=0; k<ORDER_/2; k++)
MikamiUitOpen 0:8c15b3d0523e 44 {
MikamiUitOpen 0:8c15b3d0523e 45 uk[k].u1 = 0;
MikamiUitOpen 0:8c15b3d0523e 46 uk[k].u2 = 0;
MikamiUitOpen 0:8c15b3d0523e 47 }
MikamiUitOpen 0:8c15b3d0523e 48
MikamiUitOpen 0:8c15b3d0523e 49 while (true)
MikamiUitOpen 0:8c15b3d0523e 50 {
MikamiUitOpen 0:8c15b3d0523e 51 float xn = adc_.Read(); // Read from A0
MikamiUitOpen 0:8c15b3d0523e 52 //-----------------------------------------------
MikamiUitOpen 0:8c15b3d0523e 53
MikamiUitOpen 2:d4999d914eee 54 float yn = g0_*xn;
MikamiUitOpen 0:8c15b3d0523e 55 for (int k=0; k<ORDER_/2; k++)
MikamiUitOpen 0:8c15b3d0523e 56 {
MikamiUitOpen 2:d4999d914eee 57 float un = ck_[k].a1*uk[k].u1 + ck_[k].a2*uk[k].u2 + yn;
MikamiUitOpen 2:d4999d914eee 58 yn = un + ck_[k].b1*uk[k].u1 + + ck_[k].b2*uk[k].u2;
MikamiUitOpen 0:8c15b3d0523e 59 // 計算結果の移動
MikamiUitOpen 0:8c15b3d0523e 60 uk[k].u2 = uk[k].u1;
MikamiUitOpen 0:8c15b3d0523e 61 uk[k].u1 = un;
MikamiUitOpen 0:8c15b3d0523e 62 }
MikamiUitOpen 0:8c15b3d0523e 63
MikamiUitOpen 0:8c15b3d0523e 64 //-----------------------------------------------
MikamiUitOpen 2:d4999d914eee 65 myDac_.Write(yn); // Write to DAC
MikamiUitOpen 0:8c15b3d0523e 66 }
MikamiUitOpen 0:8c15b3d0523e 67 }
MikamiUitOpen 0:8c15b3d0523e 68
MikamiUitOpen 0:8c15b3d0523e 69