71 lines
1.8 KiB
C++
71 lines
1.8 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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/*
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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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T apply(const T &sample);
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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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a notch filter with enable and filter parameters
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*/
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class NotchFilterVector3fParam {
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public:
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NotchFilterVector3fParam(void);
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void init(float sample_freq_hz);
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Vector3f apply(const Vector3f &sample);
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static const struct AP_Param::GroupInfo var_info[];
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private:
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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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float sample_freq_hz;
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float last_center_freq;
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float last_bandwidth;
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float last_attenuation;
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NotchFilter<Vector3f> filter;
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};
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typedef NotchFilter<float> NotchFilterFloat;
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typedef NotchFilter<Vector3f> NotchFilterVector3f;
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