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fft256_f32.h
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fft256_f32.h
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/*
* EasyListener for Teensy Audio Library
*
* (c) 2020 Clemens Wegener
* Bauhaus-Universität Weimar
* Department Interface Design
*
* This library uses machine learning to detect previously
* presented audio signals on the Teensy board.
*
* BSD license
*/
#ifndef analyze_fft256_f32_h_
#define analyze_fft256_f32_h_
#include <Arduino.h>
#include "AudioStream.h"
#include "arm_math.h"
#include "feature_extractor.h"
#define FFT_SIZE 256
// windows.c
extern "C" {
extern const int16_t AudioWindowHanning256[];
extern const int16_t AudioWindowBartlett256[];
extern const int16_t AudioWindowBlackman256[];
extern const int16_t AudioWindowFlattop256[];
extern const int16_t AudioWindowBlackmanHarris256[];
extern const int16_t AudioWindowNuttall256[];
extern const int16_t AudioWindowBlackmanNuttall256[];
extern const int16_t AudioWindowWelch256[];
extern const int16_t AudioWindowHamming256[];
extern const int16_t AudioWindowCosine256[];
extern const int16_t AudioWindowTukey256[];
}
class FFT256F32
{
public:
FFT256F32() : outputflag(false), window(AudioWindowHanning256) //AudioWindowHanning256
{
//prevdata = NULL;
memset(prevdata, 0, sizeof(prevdata));
memset(_float_buffer, 0, sizeof(_float_buffer));
memset(buffer, 0, sizeof(buffer));
arm_rfft_fast_init_f32(&_fft_inst, FFT_SIZE);
}
float getBin(unsigned int binNumber) {
if (binNumber > FFT_SIZE/2-1) return 0.0;
return _fftMag[binNumber];
}
int16_t getNumOfBins()
{
return FFT_SIZE/2;
}
void windowFunction(const int16_t *w) {
window = w;
}
void process(int16_t *data, uint16_t frame_num);
uint16_t getFrameNum() {return _frame_num;}
bool available() {
bool flag = outputflag;
outputflag = false;
return flag;
}
~FFT256F32(){};
private:
volatile bool outputflag;
const int16_t *window;
uint16_t _frame_num;
//int16_t *prevdata;
int16_t buffer[FFT_SIZE] __attribute__ ((aligned (4)));
int16_t prevdata[AUDIO_BLOCK_SAMPLES] __attribute__ ((aligned (4)));
float32_t _float_buffer[FFT_SIZE]__attribute__((aligned(4)));
float32_t _fftOutput[FFT_SIZE];
float32_t _fftMag[FFT_SIZE];
arm_rfft_fast_instance_f32 _fft_inst;
float _scaleFactor = 1.0/((float)FFT_SIZE/2.0);
};
#endif