kopia lustrzana https://github.com/kosme/arduinoFFT
143 wiersze
4.6 KiB
C++
143 wiersze
4.6 KiB
C++
/*
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FFT library
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Copyright (C) 2010 Didier Longueville
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Copyright (C) 2014 Enrique Condes
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Copyright (C) 2020 Bim Overbohm (template, speed improvements)
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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 ArduinoFFT_h /* Prevent loading library twice */
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#define ArduinoFFT_h
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#ifdef ARDUINO
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#if ARDUINO >= 100
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#include "Arduino.h"
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#else
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#include "WProgram.h" /* This is where the standard Arduino code lies */
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#endif
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#else
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#include <stdio.h>
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#include <stdlib.h>
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#ifdef __AVR__
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#include <avr/io.h>
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#include <avr/pgmspace.h>
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#endif
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#include "defs.h"
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#include "types.h"
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#include <math.h>
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#include <stdint.h>
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#endif
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#include "enumsFFT.h"
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// This definition uses a low-precision square root approximation instead of the
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// regular sqrt() call
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// This might only work for specific use cases, but is significantly faster.
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#ifndef FFT_SQRT_APPROXIMATION
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#ifndef sqrt_internal
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#define sqrt_internal sqrt
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#endif
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#endif
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#define FFT_LIB_REV 0x20
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template <typename T> class ArduinoFFT {
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public:
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ArduinoFFT();
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ArduinoFFT(T *vReal, T *vImag, uint_fast16_t samples, T samplingFrequency,
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bool windowingFactors = false);
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~ArduinoFFT();
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void complexToMagnitude(void) const;
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void complexToMagnitude(T *vReal, T *vImag, uint_fast16_t samples) const;
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void compute(FFTDirection dir) const;
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void compute(T *vReal, T *vImag, uint_fast16_t samples,
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FFTDirection dir) const;
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void compute(T *vReal, T *vImag, uint_fast16_t samples, uint_fast8_t power,
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FFTDirection dir) const;
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void dcRemoval(void) const;
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void dcRemoval(T *vData, uint_fast16_t samples) const;
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T majorPeak(void) const;
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void majorPeak(T *f, T *v) const;
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T majorPeak(T *vData, uint_fast16_t samples, T samplingFrequency) const;
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void majorPeak(T *vData, uint_fast16_t samples, T samplingFrequency,
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T *frequency, T *magnitude) const;
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T majorPeakParabola(void) const;
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void majorPeakParabola(T *frequency, T *magnitude) const;
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T majorPeakParabola(T *vData, uint_fast16_t samples,
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T samplingFrequency) const;
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void majorPeakParabola(T *vData, uint_fast16_t samples, T samplingFrequency,
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T *frequency, T *magnitude) const;
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uint8_t revision(void);
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void setArrays(T *vReal, T *vImag, uint_fast16_t samples = 0);
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void windowing(FFTWindow windowType, FFTDirection dir,
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bool withCompensation = false);
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void windowing(T *vData, uint_fast16_t samples, FFTWindow windowType,
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FFTDirection dir, T *windowingFactors = nullptr,
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bool withCompensation = false);
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private:
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/* Variables */
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static const T _WindowCompensationFactors[11];
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#ifdef FFT_SPEED_OVER_PRECISION
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T _oneOverSamples = 0.0;
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#endif
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bool _isPrecompiled = false;
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bool _precompiledWithCompensation = false;
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uint_fast8_t _power = 0;
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T *_precompiledWindowingFactors = nullptr;
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uint_fast16_t _samples;
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T _samplingFrequency;
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T *_vImag;
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T *_vReal;
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FFTWindow _windowFunction;
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/* Functions */
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uint_fast8_t exponent(uint_fast16_t value) const;
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void findMaxY(T *vData, uint_fast16_t length, T *maxY,
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uint_fast16_t *index) const;
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void parabola(T x1, T y1, T x2, T y2, T x3, T y3, T *a, T *b, T *c) const;
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void swap(T *a, T *b) const;
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#ifdef FFT_SQRT_APPROXIMATION
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float sqrt_internal(float x) const;
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double sqrt_internal(double x) const;
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#endif
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};
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#if defined(__AVR__) && defined(USE_AVR_PROGMEM)
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static const float _c1[] PROGMEM = {
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0.0000000000, 0.7071067812, 0.9238795325, 0.9807852804, 0.9951847267,
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0.9987954562, 0.9996988187, 0.9999247018, 0.9999811753, 0.9999952938,
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0.9999988235, 0.9999997059, 0.9999999265, 0.9999999816, 0.9999999954,
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0.9999999989, 0.9999999997};
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static const float _c2[] PROGMEM = {
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1.0000000000, 0.7071067812, 0.3826834324, 0.1950903220, 0.0980171403,
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0.0490676743, 0.0245412285, 0.0122715383, 0.0061358846, 0.0030679568,
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0.0015339802, 0.0007669903, 0.0003834952, 0.0001917476, 0.0000958738,
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0.0000479369, 0.0000239684};
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#endif
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#endif
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