echo.c File Reference

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include "echo.h"

Go to the source code of this file.

Macros
#define	MIN_TX_POWER_FOR_ADAPTION   64
#define	MIN_RX_POWER_FOR_ADAPTION   64
#define	DTD_HANGOVER   600 /* 600 samples, or 75ms */
#define	DC_LOG2BETA   3 /* log2() of DC filter Beta */

Functions
struct oslec_state *	oslec_create (int len, int adaption_mode)
	EXPORT_SYMBOL_GPL (oslec_create)
void	oslec_free (struct oslec_state *ec)
	EXPORT_SYMBOL_GPL (oslec_free)
void	oslec_adaption_mode (struct oslec_state *ec, int adaption_mode)
	EXPORT_SYMBOL_GPL (oslec_adaption_mode)
void	oslec_flush (struct oslec_state *ec)
	EXPORT_SYMBOL_GPL (oslec_flush)
void	oslec_snapshot (struct oslec_state *ec)
	EXPORT_SYMBOL_GPL (oslec_snapshot)
int16_t	oslec_update (struct oslec_state *ec, int16_t tx, int16_t rx)
	EXPORT_SYMBOL_GPL (oslec_update)
int16_t	oslec_hpf_tx (struct oslec_state *ec, int16_t tx)
	EXPORT_SYMBOL_GPL (oslec_hpf_tx)
	MODULE_LICENSE ("GPL")
	MODULE_AUTHOR ("David Rowe")
	MODULE_DESCRIPTION ("Open Source Line Echo Canceller")
	MODULE_VERSION ("0.3.0")

Macro Definition Documentation

#define DC_LOG2BETA   3 /* log2() of DC filter Beta */

Definition at line 114 of file echo.c.

#define DTD_HANGOVER   600 /* 600 samples, or 75ms */

Definition at line 113 of file echo.c.

#define MIN_RX_POWER_FOR_ADAPTION   64

Definition at line 112 of file echo.c.

#define MIN_TX_POWER_FOR_ADAPTION   64

Definition at line 111 of file echo.c.

Function Documentation

EXPORT_SYMBOL_GPL

(

oslec_create

)

EXPORT_SYMBOL_GPL

(

oslec_free

)

EXPORT_SYMBOL_GPL

(

oslec_adaption_mode

)

EXPORT_SYMBOL_GPL

(

oslec_flush

)

EXPORT_SYMBOL_GPL

(

oslec_snapshot

)

EXPORT_SYMBOL_GPL

(

oslec_update

)

EXPORT_SYMBOL_GPL

(

oslec_hpf_tx

)

MODULE_AUTHOR

(

"David Rowe"

)

MODULE_DESCRIPTION

(

"Open Source Line Echo Canceller"

)

MODULE_LICENSE

(

"GPL"

)

MODULE_VERSION

(

"0.3.0"

)

void oslec_adaption_mode	(	struct oslec_state *	ec,
		int	adaption_mode
	)

oslec_adaption_mode - set the adaption mode of a voice echo canceller context. The echo canceller context. : The mode.

Definition at line 295 of file echo.c.

struct oslec_state* oslec_create ( int  len, int  adaption_mode  )

read

oslec_create - Create a voice echo canceller context. : The length of the canceller, in samples.

Returns

: The new canceller context, or NULL if the canceller could not be created.

Definition at line 229 of file echo.c.

void oslec_flush

(

struct oslec_state *

ec

)

oslec_flush - Flush (reinitialise) a voice echo canceller context. : The echo canceller context.

Definition at line 301 of file echo.c.

void oslec_free

(

struct oslec_state *

ec

)

oslec_free - Free a voice echo canceller context. : The echo canceller context.

Definition at line 282 of file echo.c.

int16_t oslec_hpf_tx	(	struct oslec_state *	ec,
		int16_t	tx
	)

oslec_hpf_tx: Process to high pass filter the tx signal. : The echo canceller context. : The transmitted auio sample.

The return value is the HP filtered transmit sample, send this to your D/A.

Definition at line 627 of file echo.c.

void oslec_snapshot

(

struct oslec_state *

ec

)

Definition at line 327 of file echo.c.

int16_t oslec_update	(	struct oslec_state *	ec,
		int16_t	tx,
		int16_t	rx
	)

oslec_update: Process a sample through a voice echo canceller. : The echo canceller context. : The transmitted audio sample. : The received audio sample.

The return value is the clean (echo cancelled) received sample.

Definition at line 335 of file echo.c.