decibels.h File Reference

Fixed-point exponential and decibel-to-linear conversion functions. More...

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Macros
#define	EXP_FIXED_INPUT_QY   27
#define	EXP_FIXED_OUTPUT_QY   20
#define	DB2LIN_FIXED_INPUT_QY   24
#define	DB2LIN_FIXED_OUTPUT_QY   20

Functions
int32_t	exp_fixed (int32_t x)
	Compute fixed-point exponential e^x.
int32_t	db2lin_fixed (int32_t x)
	Convert decibels to linear amplitude scale 10^(x/20).

Detailed Description

Fixed-point exponential and decibel-to-linear conversion functions.

Macro Definition Documentation

DB2LIN_FIXED_INPUT_QY

#define DB2LIN_FIXED_INPUT_QY   24

DB2LIN_FIXED_OUTPUT_QY

#define DB2LIN_FIXED_OUTPUT_QY   20

EXP_FIXED_INPUT_QY

#define EXP_FIXED_INPUT_QY   27

EXP_FIXED_OUTPUT_QY

#define EXP_FIXED_OUTPUT_QY   20

Function Documentation

db2lin_fixed()

int32_t db2lin_fixed

(

int32_t

x

)

Convert decibels to linear amplitude scale 10^(x/20).

Parameters

x	Input decibel value in Q8.24 format.

Returns

Linear gain factor in Q12.20 format.

exp_fixed()

int32_t exp_fixed

(

int32_t

x

)

Compute fixed-point exponential e^x.

Parameters

x	Input argument in Q5.27 format.

Returns

Result e^x in Q12.20 format.