152edf7189
Using a global .dir-locals.el file is a better alternative than reincluding the same emacs header in every file of the project.
90 lines
2.6 KiB
C++
90 lines
2.6 KiB
C++
/*
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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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#pragma once
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#include <AP_Math/AP_Math.h>
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#include <cmath>
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#include <inttypes.h>
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/// @file LowPassFilter2p.h
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/// @brief A class to implement a second order low pass filter
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/// @authors: Leonard Hall <LeonardTHall@gmail.com>, template implmentation: Daniel Frenzel <dgdanielf@gmail.com>
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template <class T>
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class DigitalBiquadFilter {
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public:
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struct biquad_params {
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float cutoff_freq;
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float sample_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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};
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DigitalBiquadFilter();
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T apply(const T &sample, const struct biquad_params ¶ms);
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void reset();
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static void compute_params(float sample_freq, float cutoff_freq, biquad_params &ret);
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private:
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T _delay_element_1;
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T _delay_element_2;
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};
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template <class T>
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class LowPassFilter2p {
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public:
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LowPassFilter2p();
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// constructor
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LowPassFilter2p(float sample_freq, float cutoff_freq);
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// change parameters
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void set_cutoff_frequency(float sample_freq, float cutoff_freq);
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// return the cutoff frequency
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float get_cutoff_freq(void) const;
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float get_sample_freq(void) const;
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T apply(const T &sample);
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void reset(void);
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protected:
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struct DigitalBiquadFilter<T>::biquad_params _params;
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private:
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DigitalBiquadFilter<T> _filter;
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};
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// Uncomment this, if you decide to remove the instantiations in the implementation file
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/*
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template <class T>
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LowPassFilter2p<T>::LowPassFilter2p() {
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memset(&_params, 0, sizeof(_params) );
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}
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// constructor
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template <class T>
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LowPassFilter2p<T>::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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}
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*/
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typedef LowPassFilter2p<int> LowPassFilter2pInt;
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typedef LowPassFilter2p<long> LowPassFilter2pLong;
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typedef LowPassFilter2p<float> LowPassFilter2pFloat;
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typedef LowPassFilter2p<Vector2f> LowPassFilter2pVector2f;
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typedef LowPassFilter2p<Vector3f> LowPassFilter2pVector3f;
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