fir.m

浮点fir设计工具

%       AccelDSP 9.1.00 build 868 Production, compiled Feb 16 2007 
% 
%    THIS IS UNPUBLISHED, LICENSED SOFTWARE THAT IS THE CONFIDENTIAL 
%        AND PROPRIETARY PROPERTY OF XILINX OR ITS LICENSORS 
% 
%      Copyright(c) Xilinx, Inc., 2000-2007, All Rights Reserved. 
%   Reproduction or reuse, in any form, without the explicit written 
%          consent of Xilinx, Inc., is strictly prohibited. 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Description : Function definition for general FIR filter design            %
%%                                                                            %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

function outdatabuf=fir(indatabuf)

% Load the filter coefficients
coeff = load('coefficients.txt');

persistent tap_delay;

% Clear tap delay line at beginning
if isempty(tap_delay)
  tap_delay = zeros(1,length(coeff));
end

% Perform sum of products
outdatabuf = tap_delay * coeff(end:-1:1)';

% Shift tap delay line
tap_delay = [tap_delay(2:length(coeff)) indatabuf];