sdrangel/modemm17/IirFilter.h

54 wiersze
999 B
C
Czysty Zwykły widok Historia

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// Copyright 2015-2021 Mobilinkd LLC.
#pragma once
#include "Filter.h"
#include <array>
#include <cstddef>
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namespace modemm17
{
template <size_t N>
struct BaseIirFilter : FilterBase<float>
{
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BaseIirFilter(const std::array<float, N>& b, const std::array<float, N>& a) :
numerator_(b),
denominator_(a)
{
history_.fill(0.0);
}
float operator()(float 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];
}
float result = 0;
for (size_t i = 0; i != N; i++) {
result += numerator_[i] * history_[i];
}
return result;
}
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private:
const std::array<float, N>& numerator_;
const std::array<float, N> denominator_;
std::array<float, N> history_{0};
};
template <size_t N>
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BaseIirFilter<N> makeIirFilter(const std::array<float, N>& b, const std::array<float, N>& a)
{
return std::move(BaseIirFilter<N>(b, a));
}
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} // modemm17