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			47 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			47 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| ///////////////////////////////////////////////////////////////////////////////////
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| // Copyright (C) 2020 Jon Beniston, M7RCE                                        //
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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 as version 3 of the License, or                  //
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| // (at your option) any later version.                                           //
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| //                                                                               //
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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 V3 for more details.                               //
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| //                                                                               //
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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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| 
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| #ifndef INCLUDE_GOERTZEL_H
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| #define INCLUDE_GOERTZEL_H
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| 
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| #include <complex>
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| 
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| #include "export.h"
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| 
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| // Goertzel filter for calculting discrete Fourier transform for a single frequency
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| // Implementation supports non-integer multiples of fundamental frequency, see:
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| // https://asp-eurasipjournals.springeropen.com/track/pdf/10.1186/1687-6180-2012-56.pdf
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| class SDRBASE_API Goertzel
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| {
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| public:
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|     Goertzel(double frequency, int sampleRate);
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|     void reset();
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|     void filter(double sample);
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|     std::complex<double> goertzel(double lastSample);
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|     double mag();
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|     double phase();
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|     int size() { return m_sampleCount; }
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| 
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| private:
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|     double m_s0, m_s1, m_s2;
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|     double m_a, m_b;
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|     std::complex<double> m_c, m_z;
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|     int m_sampleCount;
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| };
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| 
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| #endif // INCLUDE_GOERTZEL_H
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