ardupilot/libraries/AP_HAL_SITL/DSP.h

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/*
* This file is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This file is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Code by Andy Piper
*/
#pragma once
#include <AP_HAL/AP_HAL.h>
#include "AP_HAL_SITL.h"
#include <complex>
typedef std::complex<float> complexf;
// ChibiOS implementation of FFT analysis to run on STM32 processors
class HALSITL::DSP : public AP_HAL::DSP {
public:
// initialise an FFT instance
virtual FFTWindowState* fft_init(uint16_t window_size, uint16_t sample_rate) override;
// start an FFT analysis
virtual void fft_start(FFTWindowState* state, const float* samples, uint16_t buffer_index, uint16_t buffer_size) override;
// perform remaining steps of an FFT analysis
virtual uint16_t fft_analyse(FFTWindowState* state, uint16_t start_bin, uint16_t end_bin, uint8_t harmonics, float noise_att_cutoff) override;
// STM32-based FFT state
class FFTWindowStateSITL : public AP_HAL::DSP::FFTWindowState {
friend class HALSITL::DSP;
protected:
FFTWindowStateSITL(uint16_t window_size, uint16_t sample_rate);
~FFTWindowStateSITL();
private:
complexf* buf;
};
private:
void step_hanning(FFTWindowStateSITL* fft, const float* samples, uint16_t buffer_index, uint16_t buffer_size);
void step_fft(FFTWindowStateSITL* fft);
void mult_f32(const float* v1, const float* v2, float* vout, uint16_t len);
void vector_max_float(const float* vin, uint16_t len, float* maxValue, uint16_t* maxIndex) const override;
void vector_scale_float(const float* vin, float scale, float* vout, uint16_t len) const override;
void calculate_fft(complexf* f, uint16_t length);
};