fft

Routines for interaction with fft objects. More...

Collaboration diagram for fft:

Functions
fft *	fft_new (int i_size)
	creates fft object with frequency range from 0 to i_size.
void	fft_free (fft *i_fft)
	frees fft object.
wave *	fft_wave (fft *i_fft)
	creates wave object with reverse fourier transformation.
fft *	fft_dB (fft *i_fft)
	creates fft object with sound spectra of ground tone and first overblow expressed in dB.
void	fft_save (fft *i_fft, char *i_path)
	save fft object to file.
fft *	fft_load (char *i_path, int i_size)
	load fft object from file.
peak *	fft_peak (fft *i_fft, int i_id)
	extract peak information from fft object.

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Detailed Description

Routines for interaction with fft objects.

create initial fft object for a range of 800Hz

const int fft_size = 800;
fft *fft_obj = fft_new (fft_size);

save your fft object

const char *fft_path = "my_obj.fft";
fft_save (fft_obj, fft_path)

free your fft object, when you don't need it anymore

fft_free (fft_obj);

load an fft object from a file

fft_obj = fft_load (path);

convert the amplitudes to dB

fft *fft_obj_dB = fft_dB (fft_obj);
fft_free (fft_obj_dB);

convert fft object to wave object via inverse fast fourier transformation

wave *wave_obj = fft_wave (fft_obj);
wave_free (wave_obj);

extract peaks of impedance (0), base (1) and overblow (2) sound spectra from fft object

peak *peak_obj_imp = fft_peak (fft_obj, 0);
peak *peak_obj_bas = fft_peak (fft_obj, 1);
peak *peak_obj_ovr = fft_peak (fft_obj, 2);
peak_free (peak_obj_imp);
peak_free (peak_obj_bas);
peak_free (peak_obj_ovr);

free your fft object, when you don't need it anymore

fft_free (fft_obj);

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Function Documentation

fft* fft_new

(

int

i_size

)

creates fft object with frequency range from 0 to i_size.

Parameters:

i_size

frequency range.

Returns:

fft object (free it with fft_free)

void fft_free

(

fft *

i_fft

)

frees fft object.

Parameters:

i_fft

fft object

wave* fft_wave

(

fft *

i_fft

)

creates wave object with reverse fourier transformation.

Parameters:

i_fft

fft object

Returns:

wave object (free it with wave_free)

fft* fft_dB

(

fft *

i_fft

)

creates fft object with sound spectra of ground tone and first overblow expressed in dB.

Parameters:

i_fft

fft object

Returns:

fft object (free it with fft_free);

void fft_save	(	fft *	i_fft,
		char *	i_path
	)

save fft object to file.

Parameters:

i_fft	fft object
i_path	file path to save to

fft* fft_load	(	char *	i_path,
		int	i_size
	)

load fft object from file.

Parameters:

i_path	path to load from
i_size	frequency range to load

Returns:

fft object (free it with fft_free)

peak* fft_peak	(	fft *	i_fft,
		int	i_id
	)

extract peak information from fft object.

Parameters:

i_fft	fft object
i_id	extract peaks from impedance spectrum (0), sound spectrum from ground tone (1) or sound spectrum from first overblow (2)

Returns:

peak object (free it with peak_free)