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58 lines
1.8 KiB
58 lines
1.8 KiB
// -*- 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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