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.

Type Definition

typedef struct _ModuleRepWinOverlap
{
    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
    FLOAT32* window;                              // Window coefficients
    FLOAT32* state;                               // State variable array
} ModuleRepWinOverlapClass;

Variables

Properties

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

Pins

Input Pins

Name: in

Description: audio input

Data type: float

Channel range: Unrestricted

Block size range: 32

Sample rate range: Unrestricted

Complex support: Real

Output Pins

Name: out

Description: audio output

Data type: float

MATLAB Usage

File Name: replicate_window_overlap_module.m

 M=replicate_window_overlap_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.
 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.