不韋 呂 / Mbed 2 deprecated UIT2_IIR_Direct_float

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

Dependencies:   UIT_ADDA mbed

main.cpp@5:5709a56ac600, 2014-11-12 (annotated)

Committer:
MikamiUitOpen
Date:
Wed Nov 12 10:33:59 2014 +0000
Revision:
5:5709a56ac600
Parent:
3:17b0c0c3ad5d
Child:
7:f9711acfaedf
6

Who changed what in which revision?

UserRevisionLine numberNew contents of line
MikamiUitOpen 0:3797037e0936 1 //--------------------------------------------------------------
MikamiUitOpen 0:3797037e0936 2 // IIR フィルタ，直接形，float で演算
MikamiUitOpen 0:3797037e0936 3 // Analog Input : A0
MikamiUitOpen 0:3797037e0936 4 // Analog Output: MCP4922 using SPI
MikamiUitOpen 5:5709a56ac600 5 // 2014/11/12, Copyright (c) 2014 MIKAMI, Naoki
MikamiUitOpen 0:3797037e0936 6 //--------------------------------------------------------------
MikamiUitOpen 0:3797037e0936 7
MikamiUitOpen 0:3797037e0936 8 #include "mbed.h"
MikamiUitOpen 0:3797037e0936 9
MikamiUitOpen 1:bb0320fb8ad1 10 #include "ADC_Base.hpp" // for ADC not using interrupt
MikamiUitOpen 0:3797037e0936 11 #include "DAC_MCP4922.hpp" // for DAC MCP4922
MikamiUitOpen 0:3797037e0936 12
MikamiUitOpen 0:3797037e0936 13 using namespace Mikami;
MikamiUitOpen 0:3797037e0936 14
MikamiUitOpen 0:3797037e0936 15 const int ORDER_ = 8; // order
MikamiUitOpen 0:3797037e0936 16 // 低域通過フィルタ
MikamiUitOpen 0:3797037e0936 17 // 連立チェビシェフ特性
MikamiUitOpen 0:3797037e0936 18 // 次数　　　　：6 次
MikamiUitOpen 0:3797037e0936 19 // 標本化周波数： 12.00 kHz
MikamiUitOpen 0:3797037e0936 20 // 遮断周波数　： 0.40 kHz
MikamiUitOpen 0:3797037e0936 21 // 通過域のリップル： 0.50 dB
MikamiUitOpen 0:3797037e0936 22 // 阻止域の減衰量　：40.00 dB
MikamiUitOpen 0:3797037e0936 23 const float am_[ORDER_] = {
MikamiUitOpen 0:3797037e0936 24 5.684787115202E+00, -1.354501388127E+01, 1.731054054746E+01,
MikamiUitOpen 0:3797037e0936 25 -1.251297336508E+01, 4.850124049778E+00, -7.874837248679E-01};
MikamiUitOpen 0:3797037e0936 26 const float bm_[ORDER_+1] = {
MikamiUitOpen 0:3797037e0936 27 1.000028097647E-02, -5.466081078904E-02, 1.292315717890E-01,
MikamiUitOpen 0:3797037e0936 28 -1.691239024945E-01, 1.292315717890E-01, -5.466081078904E-02,
MikamiUitOpen 0:3797037e0936 29 1.000028097647E-02};
MikamiUitOpen 0:3797037e0936 30
MikamiUitOpen 3:17b0c0c3ad5d 31 const int FS_ = 12000; // Sampling frequency: 12 kHz
MikamiUitOpen 3:17b0c0c3ad5d 32 ADC_Base adc_(A0, FS_); // for AD
MikamiUitOpen 3:17b0c0c3ad5d 33 DAC_MCP4922 myDac_; // for DA
MikamiUitOpen 0:3797037e0936 34
MikamiUitOpen 0:3797037e0936 35 int main()
MikamiUitOpen 0:3797037e0936 36 {
MikamiUitOpen 5:5709a56ac600 37 myDac_.ScfClockTim3(500000); // cutoff frequency: 5 kHz
MikamiUitOpen 0:3797037e0936 38
MikamiUitOpen 0:3797037e0936 39 float un[ORDER_]; // 過去の計算結果を格納する配列
MikamiUitOpen 0:3797037e0936 40 for (int k=0; k<ORDER_; k++) un[k] = 0;
MikamiUitOpen 0:3797037e0936 41
MikamiUitOpen 0:3797037e0936 42 while (true)
MikamiUitOpen 0:3797037e0936 43 {
MikamiUitOpen 0:3797037e0936 44 float xn = adc_.Read(); // Read from A0
MikamiUitOpen 0:3797037e0936 45 //-----------------------------------------------
MikamiUitOpen 0:3797037e0936 46
MikamiUitOpen 0:3797037e0936 47 float u0 = xn;
MikamiUitOpen 0:3797037e0936 48 for (int k=0; k<ORDER_; k++) u0 = u0 + am_[k]*un[k];
MikamiUitOpen 0:3797037e0936 49 float yn = bm_[0]*u0;
MikamiUitOpen 0:3797037e0936 50 for (int k=0; k<ORDER_; k++) yn = yn + bm_[k+1]*un[k];
MikamiUitOpen 0:3797037e0936 51
MikamiUitOpen 0:3797037e0936 52 // 計算結果の移動
MikamiUitOpen 0:3797037e0936 53 for (int k=ORDER_-1; k>0; k--) un[k] = un[k-1];
MikamiUitOpen 0:3797037e0936 54 un[0] = u0;
MikamiUitOpen 0:3797037e0936 55
MikamiUitOpen 0:3797037e0936 56 //-----------------------------------------------
MikamiUitOpen 0:3797037e0936 57 myDac_.Write(yn); // Write to DAC
MikamiUitOpen 0:3797037e0936 58 }
MikamiUitOpen 0:3797037e0936 59 }