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Overview

Subband smoothing across frequency bins

Discussion

This module performs smoothing across frequency bins. Smoothing is done by averaging multiple bins to the left and right of a particular frequency sample. The smoothing only operates on real data. To smooth complex data it must first be decomposed into real and imaginary components.

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The module is designed to work with the wola_analysis_subsystem.m and the sample rate specified equals the decimated subband sample rate.

Type Definition

Code Block
typedef struct _ModuleSbSmoothFract32
{
    ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
    INT32 type;                                   // Determines which type of smoothing is applied: Linear=0, Logarithmic=1, Custom=2
    FLOAT32 startFreq;                            // Starting frequency for the smoothing operation
    FLOAT32 width;                                // Amount of smoothing
    INT32* startIndex;                            // Starting index for the averaging process.
    INT32* endIndex;                              // Ending index for the averaging process.
    fract32* oneOverN;                            // Precomputed 1/N for averaging.
    fract32* cumSum;                              // Cumulative sum of values from the start of the buffer. This holds 64-bit values.
} ModuleSbSmoothFract32Class;

Variables

Properties

Name

Type

Usage

isHidden

Default value

Range

Units

type

int

parameter

0

1

0:2

startFreq

float

parameter

0

0

0:24000

Hz

width

float

parameter

0

0.1667

0:2400

startIndex

int*

derived

1

[257 x 1]

Unrestricted

endIndex

int*

derived

1

[257 x 1]

Unrestricted

oneOverN

fract32*

derived

1

[257 x 1]

Unrestricted

cumSum

fract32*

state

1

[516 x 1]

Unrestricted

Pins

Input Pins

Name: in

Description: audio input

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Sample rate range: Unrestricted

Complex support: Real

Output Pins

Name: out

Description: audio output

Data type: fract32

MATLAB Usage

File Name: sb_smooth_fract32_module.m

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