www.pudn.com > cyclostationary_toolbox.rar > cyclic_autocorrelation_fast.m, change:1997-11-24,size:1113b


function R=cyclic_autocorrelation_fast(x,T,max_tau)
%
% CYCLIC_AUTOCORRELATION_FAST
%              
%              calculates the cyclic autocorrelation for signal x
%              at frequency alpha=1/T using a fast
%              approximation based on the synchronous average of the
%              time varying autocorrelation.  Fundamental signal
%              period can be defined as a single period or as a sequence
%              of once per period pulse times.
%             
%              R(k*alpha,tau)=E{x(t-tau/2)x(t+tau/2)exp(-jk(alpha)t)}
%              for k=0 ... 1/alpha
%
%              R=cyclic_autocorrelation_fast(x,T,max_tau)
%
%              calculate autocorrelation up to max_tau time lags
%
%              if T is a scalar, then T defined the fundamental
%              cyclic period
%
%              if T is a vector, then T defines a series of once
%              per revolution impulses

% File: cyclic_autocorrelation_fast.m
% Last Revised: 24/11/97
% Created: 24/11/97
% Author: Andrew C. McCormick
% (C) University of Strathclyde

R=cyclic_cross_correlation_fast(x,x,T,max_tau);