function output = convforhs(input)
g = [1 0 1 1 0 1 1;
    1 1 0 0 1 0 1;
    1 1 1 1 1 0 1];
len = length(input);
line1 = mod(conv(input,g(1,:)),2);
line2 = mod(conv(input,g(2,:)),2);
line3 = mod(conv(input,g(3,:)),2);
line = [line1(1:len);line2(1:len);line3(1:len)];
output = reshape(line,1,3*len);