dt_window.c File Reference

#include <stdio.h>
#include <stdint.h>
#include <math.h>
#include <string.h>
#include "dt_window.h"

Include dependency graph for dt_window.c:

Go to the source code of this file.

Data Structures
struct	ts_window_function
struct	x_dt_window
Defines
#define	NUMBER_OF_WINDOW_FUNCTIONS   (sizeof(discrete_time_window_function_table) / sizeof(discrete_time_window_function_table[0]))
Functions
static double	hamming_eq (int32_t num, int32_t den)
static double	hanning_eq (int32_t num, int32_t den)
static double	blackman_eq (int32_t num, int32_t den)
static double *	dt_window_compute (te_dt_window_type type, uint32_t size)
dt_window	dt_window_create (te_dt_window_type type, uint32_t size)
	Pointer to an discrete time window object.
void	dt_window_apply (dt_window w, double *data)
	Applies a discrete time window to real waveform data.
void	dt_window_destroy (dt_window *w)
	De-allocates the discrete time window object.
Variables
static const ts_window_function	discrete_time_window_function_table [DT_NUMBER_OF_WINDOWS]

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Define Documentation

#define NUMBER_OF_WINDOW_FUNCTIONS   (sizeof(discrete_time_window_function_table) / sizeof(discrete_time_window_function_table[0]))

Definition at line 70 of file dt_window.c.

Referenced by dt_window_create().

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Function Documentation

static double blackman_eq	(	int32_t	num,
		int32_t	den
	)			[static]

Definition at line 146 of file dt_window.c.

void dt_window_apply	(	dt_window	w,
		double *	data
	)

Applies a discrete time window to real waveform data.

See also:

dt_window_create

Parameters:

	w	pointer to discrete time window object.
	data	pointer to real array to apply discrete time window funtion to.

Definition at line 95 of file dt_window.c.

References x_dt_window::elements, and x_dt_window::size.

Referenced by fwin_apply_window(), fwin_reapply_window(), and morse_create_fft_amp_array().

static double * dt_window_compute	(	te_dt_window_type	type,
		uint32_t	size
	)			[static]

Definition at line 117 of file dt_window.c.

References ts_window_function::function.

Referenced by dt_window_create().

dt_window dt_window_create	(	te_dt_window_type	type,
		uint32_t	size
	)

Pointer to an discrete time window object.

Used to limit FFT leakage.

Parameters:

	type	window function (hamming, hanning).
	size	the size of the window function, same as the audio packet data size.

Definition at line 75 of file dt_window.c.

References dt_window_compute(), x_dt_window::elements, NUMBER_OF_WINDOW_FUNCTIONS, x_dt_window::size, and x_dt_window::window_function.

Referenced by fwin_apply_window(), and morse_start_threads().

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void dt_window_destroy

(

dt_window *

w

)

De-allocates the discrete time window object.

See also:

dt_window_create

Definition at line 108 of file dt_window.c.

Referenced by free_all().

static double hamming_eq	(	int32_t	num,
		int32_t	den
	)			[static]

Definition at line 136 of file dt_window.c.

static double hanning_eq	(	int32_t	num,
		int32_t	den
	)			[static]

Definition at line 141 of file dt_window.c.

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Variable Documentation

const ts_window_function discrete_time_window_function_table[DT_NUMBER_OF_WINDOWS] [static]

Initial value:

 {
    {"Hamming",     &hamming_eq},
    {"Hanning",     &hanning_eq},
    {"Blackman",    &blackman_eq}
}

Definition at line 65 of file dt_window.c.