fir_win.c File Reference

#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <stdint.h>
#include "fir_win.h"
#include "dt_window.h"

Include dependency graph for fir_win.c:

Go to the source code of this file.

Data Structures
struct	ts_fwin
	Private Data for Fir Window Filter. More...
Defines
#define	FW_2PI   (2.0 * M_PI)
#define	DOUBLE_Z_FIR   2
Typedefs
typedef void(*	fwin_filter_function )(p_fwin fw)
Functions
static void	fwin_apply_window (p_fwin fw)
static void	fwin_reapply_window (p_fwin fw)
static void	band_pass (p_fwin fw)
static void	band_stop (p_fwin fw)
static void	low_pass (p_fwin fw)
static void	high_pass (p_fwin fw)
static void	average (p_fwin fw)
p_fwin	fwin_create (double sample_freq, double f_low, double f_high, te_fir_win_filter_type filter_type, te_fir_win_window_type window_type, uint32_t taps)
void	fwin_change_freq (p_fwin fw, double f_low, double f_high)
void	fwin_apply (p_fwin fw, double *data, uint32_t size)
void	fwin_destroy (p_fwin *fw)
Variables
static const te_dt_window_type	FW_WINDOW_TABLE [FW_NUMBER_OF_WINDOW_TYPES]
static const fwin_filter_function	FW_FILTER_FUNCTIONS [FW_NUMBER_OF_FILTER_TYPES]

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Define Documentation

#define DOUBLE_Z_FIR   2

Definition at line 67 of file fir_win.c.

Referenced by fwin_create().

#define FW_2PI   (2.0 * M_PI)

Definition at line 66 of file fir_win.c.

Referenced by band_pass().

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Typedef Documentation

typedef void( * fwin_filter_function)(p_fwin fw)

Definition at line 112 of file fir_win.c.

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Function Documentation

static void average

(

p_fwin

fw

)

[static]

Definition at line 271 of file fir_win.c.

References ts_fwin::h, and ts_fwin::taps.

static void band_pass

(

p_fwin

fw

)

[static]

Definition at line 233 of file fir_win.c.

References ts_fwin::f_high, ts_fwin::f_low, FW_2PI, ts_fwin::h, ts_fwin::sample_freq, and ts_fwin::taps.

static void band_stop

(

p_fwin

fw

)

[static]

Todo:

Implement band_stop.

Definition at line 256 of file fir_win.c.

void fwin_apply	(	p_fwin	fw,
		double *	data,
		uint32_t	size
	)

Apply the FIR filter to sampled data.

Parameters:

	fw	Pointer to the FIR filter object.
	data	Pointer to the data to be filtered.
	size	Number of data points in data.

Definition at line 190 of file fir_win.c.

References ts_fwin::h, ts_fwin::taps, ts_fwin::z, and ts_fwin::z_state.

Referenced by morse_code().

static void fwin_apply_window

(

p_fwin

fw

)

[static]

Todo:

These could be combined.

Definition at line 282 of file fir_win.c.

References dt_window_apply(), dt_window_create(), FW_NONE, FW_NUMBER_OF_WINDOW_TYPES, FW_WINDOW_TABLE, ts_fwin::h, ts_fwin::h_window, ts_fwin::taps, and ts_fwin::window_type.

Referenced by fwin_create().

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void fwin_change_freq	(	p_fwin	fw,
		double	f_low,
		double	f_high
	)

Changes the frequency response of an existing FIR filter.

Parameters:

	fw	Pointer to existing FIR filter object.
	f_low	New low frequency cut-off in Hertz.
	f_high	New high frequency cut-off in Hertz.

Definition at line 174 of file fir_win.c.

References ts_fwin::f_high, ts_fwin::f_low, ts_fwin::filter_type, FW_FILTER_FUNCTIONS, and fwin_reapply_window().

Referenced by morse_recompute_filter().

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p_fwin fwin_create	(	double	sample_freq,
		double	f_low,
		double	f_high,
		te_fir_win_filter_type	filter_type,
		te_fir_win_window_type	window_type,
		uint32_t	taps
	)

Creates a FIR filter via the window method.

Parameters:

	sample_freq	Sample frequency in Hertz.
	f_low	Low frequency cut-off in Hertz.
	f_high	High frequency cut-off in Hertz.
	filter_type	Filter type, band-pass, high-pass, low-pass, etc...
	window_type	Window applied to the FIR filter coefficients.
	taps	Number of FIR filter taps (N).

Returns:

Pointer to the FIR filter object.

Definition at line 133 of file fir_win.c.

References DOUBLE_Z_FIR, ts_fwin::f_high, ts_fwin::f_low, ts_fwin::filter_type, FW_FILTER_FUNCTIONS, FW_NUMBER_OF_FILTER_TYPES, fwin_apply_window(), ts_fwin::h, ts_fwin::h_window, ts_fwin::sample_freq, ts_fwin::taps, ts_fwin::window_type, ts_fwin::z, and ts_fwin::z_state.

Referenced by morse_start_threads().

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void fwin_destroy

(

p_fwin *

fw

)

Destroys, and frees all memory from a window FIR filter object.

Parameters:

fw

Pointer to the FIR filter object to be freed.

Definition at line 220 of file fir_win.c.

Referenced by free_all().

static void fwin_reapply_window

(

p_fwin

fw

)

[static]

Definition at line 295 of file fir_win.c.

References dt_window_apply(), FW_NONE, ts_fwin::h, ts_fwin::h_window, and ts_fwin::window_type.

Referenced by fwin_change_freq().

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static void high_pass

(

p_fwin

fw

)

[static]

Todo:

Implement high_pass.

Definition at line 266 of file fir_win.c.

static void low_pass

(

p_fwin

fw

)

[static]

Todo:

Implement low_pass.

Definition at line 261 of file fir_win.c.

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Variable Documentation

const fwin_filter_function FW_FILTER_FUNCTIONS[FW_NUMBER_OF_FILTER_TYPES] [static]

Initial value:

 {
    band_pass,      
    band_stop,      
    low_pass,       
    high_pass,      
    average         
}

Definition at line 125 of file fir_win.c.

Referenced by fwin_change_freq(), and fwin_create().

const te_dt_window_type FW_WINDOW_TABLE[FW_NUMBER_OF_WINDOW_TYPES] [static]

Initial value:

 {
    0,                      
    DT_HAMMING_WINDOW,      
    DT_HANNING_WINDOW,      
    DT_BLACKMAN_WINDOW      
}

Definition at line 98 of file fir_win.c.

Referenced by fwin_apply_window().