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71 lines
2.2 KiB
71 lines
2.2 KiB
/* |
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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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/* |
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notch filter with settable sample rate, center frequency, bandwidth and attenuation |
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Design by Leonard Hall |
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*/ |
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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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#include <AP_Param/AP_Param.h> |
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template <class T> |
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class NotchFilter { |
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public: |
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// set parameters |
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void init(float sample_freq_hz, float center_freq_hz, float bandwidth_hz, float attenuation_dB); |
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void init_with_A_and_Q(float sample_freq_hz, float center_freq_hz, float A, float Q); |
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T apply(const T &sample); |
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void reset(); |
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// calculate attenuation and quality from provided center frequency and bandwidth |
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static void calculate_A_and_Q(float center_freq_hz, float bandwidth_hz, float attenuation_dB, float& A, float& Q); |
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private: |
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bool initialised; |
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float b0, b1, b2, a1, a2, a0_inv; |
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T ntchsig, ntchsig1, ntchsig2, signal2, signal1; |
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}; |
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/* |
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notch filter enable and filter parameters |
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*/ |
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class NotchFilterParams { |
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public: |
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NotchFilterParams(void); |
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static const struct AP_Param::GroupInfo var_info[]; |
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float center_freq_hz(void) const { return _center_freq_hz; } |
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float bandwidth_hz(void) const { return _bandwidth_hz; } |
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float attenuation_dB(void) const { return _attenuation_dB; } |
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uint8_t enabled(void) const { return _enable; } |
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protected: |
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AP_Int8 _enable; |
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AP_Float _center_freq_hz; |
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AP_Float _bandwidth_hz; |
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AP_Float _attenuation_dB; |
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}; |
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typedef NotchFilter<float> NotchFilterFloat; |
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typedef NotchFilter<Vector2f> NotchFilterVector2f; |
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typedef NotchFilter<Vector3f> NotchFilterVector3f; |
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