function y = rsc_encode(g, x, terminated)% Copyright Nov. 1998 Yufei Wu% MPRG lab, Virginia Tech.% for academic use only% encodes a block of data x (0/1)with a recursive systematic% convolutional code with generator vectors in g, and% returns the output in y (0/1).% if terminated>0, the trellis is perfectly terminated% if terminated<0, it is left unterminated;% determine the constraint length (K), memory (m), and rate (1/n)% and number of information bits.[n,K] = size(g);m = K - 1;if terminated>0  L_info = length(x);  L_total = L_info + m;else  L_total = length(x);  L_info = L_total - m;end  % initialize the state vectorstate = zeros(1,m);% generate the codewordfor i = 1:L_total   if terminated<0 | (terminated>0 & i<=L_info)      d_k = x(1,i);   elseif terminated>0 & i>L_info      % terminate the trellis      d_k = rem( g(1,2:K)*state', 2 );   end    a_k = rem( g(1,:)*[d_k state]', 2 );   [output_bits, state] = encode_bit(g, a_k, state);   % since systematic, first output is input bit   output_bits(1,1) = d_k;   y(n*(i-1)+1:n*i) = output_bits;end