adi_fft.h

Go to the documentation of this file.

/*************************************************************************/
#ifndef _ADI_FFT_H_
#define _ADI_FFT_H_
 
/******************************************************************************/
/***************************** Include Files **********************************/
/******************************************************************************/
 
#include <stdint.h>
#include <stdbool.h>
#include "adi_fft_windowing.h"
 
/******************************************************************************/
/************************ Macros/Constants ************************************/
/******************************************************************************/
 
/* Maximum number of default samples used for FFT analysis (must be <=2048)
 * FFT length = FFT samples. FFT length(samples) are supported only as power of 2
 * e.g. 512, 1024, 2048
 * */
#if !defined(ADI_FFT_MAX_SAMPLES)
#define ADI_FFT_MAX_SAMPLES     2048
#endif
 
/******************************************************************************/
/************************ Public Declarations *********************************/
/******************************************************************************/
 
typedef float(*adi_fft_data_to_volt_conv)(int32_t, uint8_t);
typedef int32_t(*adi_fft_code_to_straight_bin_conv)(uint32_t, uint8_t);
 
/* FFT windowing type */
enum adi_fft_windowing_type {
    BLACKMAN_HARRIS_7TERM,
    RECTANGULAR
};
 
/* FFT init parameters specific to device */
struct adi_fft_init_params {
    /* Device reference voltage */
    float vref;
    /* Device sample rate */
    uint32_t sample_rate;
    /* Samples count */
    uint16_t samples_count;
    /* Input data full scale value */
    int32_t input_data_full_scale;
    /* Input data zero scale value */
    int32_t input_data_zero_scale;
    /* Convert input data to voltage without respect to vref */
    adi_fft_data_to_volt_conv convert_data_to_volt_without_vref;
    /* Convert input data to voltage with respect to vref */
    adi_fft_data_to_volt_conv convert_data_to_volt_wrt_vref;
    /* Convert code to straight binary data */
    adi_fft_code_to_straight_bin_conv convert_code_to_straight_binary;
};
 
/* FFT processing parameters */
struct adi_fft_processing {
    /* Device reference voltage */
    float vref;
    /* Device sample rate */
    uint32_t sample_rate;
    /* Input data full scale value */
    int32_t input_data_full_scale;
    /* Input data zero scale value */
    int32_t input_data_zero_scale;
    /* Convert input data to voltage without respect to vref */
    adi_fft_data_to_volt_conv cnv_data_to_volt_without_vref;
    /* Convert input data to voltage with respect to vref */
    adi_fft_data_to_volt_conv cnv_data_to_volt_wrt_vref;
    /* Convert code to straight binary data */
    adi_fft_code_to_straight_bin_conv cnv_code_to_straight_binary;
    /* FFT length */
    uint16_t fft_length;
    /* FFT bin width */
    float bin_width;
    /* Input data (unformatted/straight binary for ADCs) */
    int32_t input_data[ADI_FFT_MAX_SAMPLES];
    /* Maximum length of FFT magnitude */
    float fft_magnitude[ADI_FFT_MAX_SAMPLES / 2];
    /* Magnitude with windowing correction */
    float fft_magnitude_corrected[ADI_FFT_MAX_SAMPLES / 2];
    /* FFT effective gain */
    float fft_dB[ADI_FFT_MAX_SAMPLES / 2];
    /* Maximum length of FFT input array supporred - Real + Imaginary components */
    float fft_input[ADI_FFT_MAX_SAMPLES * 2];
    /* FFT bins excluding DC, fundamental and Harmonics */
    float noise_bins[ADI_FFT_MAX_SAMPLES / 2];
    /* FFT window type */
    enum adi_fft_windowing_type window;
    /* FFT done status */
    bool fft_done;
};
 
/* FFT meausurement parameters */
struct adi_fft_measurements {
    /* Harmonics, including their power leakage */
    float harmonics_power[ADI_FFT_NUM_OF_TERMS];
    /* Harmonic magnitudes for THD */
    float harmonics_mag_dbfs[ADI_FFT_NUM_OF_TERMS];
    /* Harmonic frequencies for THD */
    uint16_t harmonics_freq[ADI_FFT_NUM_OF_TERMS];
    /* Fundamental in volts */
    float fundamental;
    /* Peak spurious noise (amplitude) */
    float pk_spurious_noise;
    /* Peak Spurious Frequency */
    uint16_t pk_spurious_freq;
    /* Total Harmonic Distortion */
    float THD;
    /* Signal to Noise Ratio */
    float SNR;
    /* Dynamic Range */
    float DR;
    /* Signal to Noise And Distortion ratio */
    float SINAD;
    /* Spurious Free Dynamic Range, dBc */
    float SFDR_dbc;
    /* Spurious Free Dynamic Range, dbFS */
    float SFDR_dbfs;
    /* ENOB - Effective Number Of Bits */
    float ENOB;
    /* RMS noise */
    float RMS_noise;
    float average_bin_noise;
    /* Maximum amplitude in volts */
    float max_amplitude;
    /* Minimum amplitude in volts */
    float min_amplitude;
    /* Peak to Peak amplitude in volts */
    float pk_pk_amplitude;
    /* DC bias in volts */
    float DC;
    /* Transition noise */
    float transition_noise;
    /* Maximum amplitude in LSB */
    uint32_t max_amplitude_LSB;
    /* Minimum amplitude in LSB */
    uint32_t min_amplitude_LSB;
    /* Peak to Peak amplitude in LSB */
    uint32_t pk_pk_amplitude_LSB;
    /* DC bias in LSB */
    int32_t DC_LSB;
    /* Transition noise in LSB */
    float transition_noise_LSB;
};
 
int adi_fft_init(struct adi_fft_init_params *param,
         struct adi_fft_processing *fft_proc,
         struct adi_fft_measurements *fft_meas);
int adi_fft_update_params(struct adi_fft_init_params *param,
              struct adi_fft_processing *fft_proc);
int adi_fft_perform(struct adi_fft_processing *fft_proc,
            struct adi_fft_measurements *fft_meas);
 
#endif // !_ADI_FFT_H_