32 init_ pbfdaf

Purpose

Creates and initializes the variables required for the Partitioned Block Frequency Domain Adaptive Filter (PBFDAF) algorithm.

Syntax

[W,x,d,e,y,Px,X,w]=init_pbfdaf(L,M,P)
[W,x,d,e,y,Px,X,w]=init_pbfdaf(L,M,P,W0,X0,d0)

Description

The variables of the PBFDAF are similar to those of the BFDAF (see Fig. 4.2) and are summarized below . The FFT length B is internally calculated using the equation $B= 2 ^{nextpow2(L+M-1)}$.

Input Parameters [Size]:: 
   L  : number of new input samples per block
   M  : filter partition length (in time domain)
   P  : number of partitions (total filter length = P*M)
   W0 : initial matrix of filter coefficients [B x P]
   X0 : initial matrix of frequency domain input signal [B x P]
   d0 : initial desired response vector [L x 1]

Output parameters [default]::
   W  : initialized matrix of filter coef. [zeros]
   x  : initialized overlap-save input buffer  
   d  : initialized desired response [white noise]
   e  : initialized error vector in t-domain
   y  : initialized filter output in t-domain 
   Px : initialized estimate of the input power (Bx1)
   X  : initialized input samples matrix [zeros]
   w  : time domain filter coefficients vector

Example

P  = 16;                 % partitions
L  = 128;                % Block length
M  = 128;                % 2048-long filter 
B  = 2^nextpow2(L+M-1);  % FFT length
W0 = zeros(B,P);         % initial filter coef. 
X0 = rand(B,P);          % initial input buffer
d0 = rand(L,1);          % desired block

% Create and initialize a PBFDAF FIR filter
[W,x,d,e,y,Px,X,w]=init_pbfdaf(L,M,P,W0,X0,d0);

Remarks

• Supports both real and complex signals and filters.
• Use input parameters 4 through 6 to initialize the algorithm storage. This is helpful when the adaptation process is required to start from a known operation point calculated off-line or from previous simulations.

See Also

ASPTPBFDAF, ECHO_ PBFDAF.