m17-cxx-demod/include/m17cxx/IirFilter.h

52 wiersze
1.0 KiB
C++

// Copyright 2015-2020 Mobilinkd LLC.
#pragma once
#include "Filter.h"
#include <array>
namespace mobilinkd
{
template <typename FloatType, size_t N>
struct BaseIirFilter : FilterBase<FloatType>
{
const std::array<FloatType, N>& numerator_;
const std::array<FloatType, N> denominator_;
std::array<FloatType, N> history_{0};
BaseIirFilter(const std::array<FloatType, N>& b, const std::array<FloatType, N>& a)
: numerator_(b), denominator_(a)
{
history_.fill(0.0);
}
FloatType operator()(FloatType input) {
for (size_t i = N - 1; i != 0; i--) history_[i] = history_[i - 1];
history_[0] = input;
for (size_t i = 1; i != N; i++) {
history_[0] -= denominator_[i] * history_[i];
}
FloatType result = 0;
for (size_t i = 0; i != N; i++) {
result += numerator_[i] * history_[i];
}
return result;
}
};
template <typename FloatType, size_t N>
BaseIirFilter<FloatType, N> makeIirFilter(
const std::array<FloatType, N>& b, const std::array<FloatType, N>& a)
{
return std::move(BaseIirFilter<FloatType, N>(b, a));
}
} // mobilinkd