wspace.m

此源码是文档simulation.rar__关于光孤子在光纤耦合器中传输的仿真研究的matlab程序

function w = wspace(t,nt); 
 
% This function constructs a linearly-spaced vector of angular 
% frequencies that correspond to the points in an FFT spectrum. 
% The second half of the vector is aliased to negative 
% frequencies. 
%  
% USAGE 
% 
% w = wspace(tv); 
% w = wspace(t,nt); 
% 
% INPUT 
% 
% tv - vector of linearly-spaced time values 
% t - scalar representing the periodicity of the time sequence 
% nt - Number of points in time sequence  
%      (should only be provided if first argument is scalar) 
% 
% OUTPUT 
% 
% w - vector of angular frequencies 
%  
% EXAMPLE 
% 
%   t = linspace(-10,10,2048)';   % set up time vector 
%   x = exp(-t.^2);               % construct time sequence 
%   w = wspace(t);                % construct w vector 
%   Xhat = fft(x);                % calculate spectrum 
%   plot(w,abs(Xhat))             % plot spectrum 
% 
% AUTHOR:  Thomas E. Murphy ([e-mail]) 
 
if (nargin<2) 
  nt = length(t); 
  dt = t(2) - t(1); 
  t = t(nt) - t(1) + dt; 
end 
 
if (nargin == 2) 
  dt = t/nt; 
end 
 
w = 2*pi*(0:nt-1)'/t; 
kv = find(w >= pi/dt); 
w(kv) = w(kv) - 2*pi/dt;