59 lines
1.8 KiB
C++
59 lines
1.8 KiB
C++
// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
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/*
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef LOWPASSFILTER2P_H
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#define LOWPASSFILTER2P_H
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/// @file LowPassFilter.h
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/// @brief A class to implement a second order low pass filter
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/// Author: Leonard Hall <LeonardTHall@gmail.com>
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class LowPassFilter2p
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{
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public:
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// constructor
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LowPassFilter2p(float sample_freq, float cutoff_freq) {
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// set initial parameters
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set_cutoff_frequency(sample_freq, cutoff_freq);
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_delay_element_1 = _delay_element_2 = 0;
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}
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// change parameters
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void set_cutoff_frequency(float sample_freq, float cutoff_freq);
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// apply - Add a new raw value to the filter
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// and retrieve the filtered result
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float apply(float sample);
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// return the cutoff frequency
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float get_cutoff_freq(void) const {
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return _cutoff_freq;
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}
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private:
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float _cutoff_freq;
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float _a1;
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float _a2;
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float _b0;
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float _b1;
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float _b2;
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float _delay_element_1; // buffered sample -1
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float _delay_element_2; // buffered sample -2
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};
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#endif // LOWPASSFILTER2P_H
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