f_subsignal.asv

digital signal processing常用工具箱

function X = f_subsignals (p)
% F_SUBSIGNALS: Compute a matrix of bandlimited subsignals
%
% Inputs: p = subsignal length
%
% Outputs: X = p by 4 matrix containing the samples of four
%              subsignals in each column. Each subsignal is
%              bandlimited to fs/4.

fs = 1;
A = zeros(p,1);
F_0 = fs/4;

% Construct signals

for k = 1 : 4
   switch (k)
      case 1,                                  % cosine
         for i = 1 : N
            if abs(f(i)) <= F_0
                A(i) = cos(pi*f(i)/(2*F_0));
            end
         end
      case 2,
         for i = 1 : N
            if abs(f(i)) <= F_0
                A(i) = 1 - abs(f(i))/F_0;
            end
         end
      case 3,
          for i = 1 : N
             if abs(f(i)) <= F_0
                 A(i) = abs(sin(pi*f(i)/F_0));               
             end
          end
      case 4,
         for i = 1 : N
            if abs(f(i)) <= F_0
                A(i) = 1 - sqrt(abs(f(i))/F_0);
            end
         end
   end
   X(:,k) = ifft (A);
end