Overview

Replicates, windows, and overlap adds signals

Discussion

This module forms part of the synthesis bank of a filterbank and typically follows the inverse FFT. The module replicates the input N times where N = (window length) / (ifftSize). The replicated signal is multiplied by the window and the result is added to a state buffer. The first OLEN samples of the state buffer are output and then the state buffer is left shifted by OLEN samples.

This module operates on fract32 data.

Type Definition

typedef struct _ModuleRepWinOverlapFract32
{
    ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
    INT32 winLen;                                 // Length of the window
    INT32 repCount;                               // Number of times to replicate the input prior to applying the window
    fract32* window;                              // Window coefficients
    fract32* state;                               // State variable array
} ModuleRepWinOverlapFract32Class;

Variables

Properties

Name	Type	Usage	isHidden	Default value	Range	Units
winLen	int	const	0	128	Unrestricted
repCount	int	const	1	4	Unrestricted
window	fract32*	parameter	0	[128 x 1]	Unrestricted
state	fract32*	state	1	[128 x 1]	Unrestricted

Pins

Input Pins

Name: in

Description: audio input

Data type: fract32

Channel range: Unrestricted

Block size range: 32

Sample rate range: Unrestricted

Complex support: Real

Output Pins

Name: out

Description: audio output

Data type: fract32

MATLAB Usage

File Name: replicate_window_overlap_fract32_module.m

 M = replicate_window_overlap_fract32_module(NAME, ILEN, WLEN, OLEN)
 Creates a module which performs 4 operations:  replicates a signal,
 applies a window, adds the result to a state buffer, and then 
 outputs a single block of data from the state buffer.  This modules
 forms the core of the synthesis bank of frequency domain filterbanks.
 This module applies to fract32 data.  Arguments:
    NAME - name of the module.
    ILEN - length of the input block of data (equal to IFFT size)
    WLEN - length of the window to apply.  Also, the length of the
           internal state buffer.
    OLEN - number of output samples to be taken from the buffer.
 The length of the window (WLEN) must be a multiple of the IFFT size
 (ILEN).  By default, the module using a Hanning (raised cosine) window.