function [cw] = g_TriSpec_ww1w_slice(cum_4,C_LENGTH,NF,ADD_POLYSPECTRA_WINDOW)
%------------------------------------------------------------------------------
%	g_TriSpec_ww1w_slice.m
%	This function generate the fourth order cross cumulant of the Fourier Transform
%  of 4 signals.
%
% Usage:
%	 [cw] = g_TriSpec_ww1w_slice(cum_4,C_LENGTH,NF);
% Where
%	cum_4     : the cross cumulant matrix of four signals, L x L x L.
%              where L = 2*C_LENGTH+1.
%	C_LENGTH  : the maximum argument of the cross cumulant.
%	NF        : Length of FFT. NF must be greater than 6*C_LENGTH+1.
% 
%  Designed by Binning Chen on March 26, 2001.
%-------------------------------------------------------------------------------

[ind_1 ind_2 ind_3]=ndgrid(-C_LENGTH:C_LENGTH, -C_LENGTH:C_LENGTH, -C_LENGTH:C_LENGTH);

ind_sum=ind_1+ind_2-ind_3;

cum_sum=zeros(6*C_LENGTH+1,1);

for tao=-3*C_LENGTH:3*C_LENGTH
   cum_sum(tao+3*C_LENGTH+1)=sum(cum_4(find(ind_sum==tao)));
end
    
cum_sum_NF=zeros(NF,1);

cum_sum_NF(NF/2-3*C_LENGTH+1:NF/2+3*C_LENGTH+1)=cum_sum;

beta=6;

kaiser_win=kaiser(NF, beta);

if ADD_POLYSPECTRA_WINDOW
   cum_sum_NF = cum_sum_NF .* kaiser_win;
end

cw=fft(fftshift(cum_sum_NF));