DiFipp/include/Butterworth.h

48 wiersze
1.0 KiB
C++

#pragma once
#include "DigitalFilter.h"
#include "typedefs.h"
#include <cmath>
#include <complex>
namespace fratio {
// https://www.dsprelated.com/showarticle/1119.php
template <typename T>
class Butterworth : public DigitalFilter<T> {
public:
T PI = static_cast<T>(M_PI);
public:
enum class Type {
LowPass,
HighPass
};
// public:
// static double minimumRequiredFrequency(...);
public:
Butterworth(Type type = Type::LowPass);
Butterworth(int order, T fc, T fs, Type type = Type::LowPass);
void setFilterParameters(int order, T fc, T fs);
private:
void initialize(int order, T fc, T fs);
void computeDigitalRep();
std::complex<T> generateAnalogPole(T fpw, int k);
vectX_t<std::complex<T>> generateAnalogZeros();
void scaleAmplitude(Eigen::Ref<vectX_t<T>> aCoeff, Eigen::Ref<vectX_t<T>> bCoeff);
private:
Type m_type;
int m_order;
T m_fc;
T m_fs;
vectX_t<std::complex<T>> m_poles;
};
} // namespace fratio
#include "Butterworth.tpp"