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54 lines
999 B
C++
54 lines
999 B
C++
// Copyright 2015-2021 Mobilinkd LLC.
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#pragma once
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#include "Filter.h"
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#include <array>
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#include <cstddef>
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namespace modemm17
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{
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template <size_t N>
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struct BaseIirFilter : FilterBase<float>
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{
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BaseIirFilter(const std::array<float, N>& b, const std::array<float, N>& a) :
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numerator_(b),
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denominator_(a)
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{
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history_.fill(0.0);
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}
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float operator()(float input) {
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for (size_t i = N - 1; i != 0; i--) history_[i] = history_[i - 1];
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history_[0] = input;
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for (size_t i = 1; i != N; i++) {
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history_[0] -= denominator_[i] * history_[i];
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}
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float result = 0;
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for (size_t i = 0; i != N; i++) {
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result += numerator_[i] * history_[i];
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}
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return result;
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}
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private:
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const std::array<float, N>& numerator_;
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const std::array<float, N> denominator_;
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std::array<float, N> history_{0};
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};
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template <size_t N>
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BaseIirFilter<N> makeIirFilter(const std::array<float, N>& b, const std::array<float, N>& a)
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{
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return std::move(BaseIirFilter<N>(b, a));
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}
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} // modemm17
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