function out = diffeqn(in, sigma, omega)
M = sigma*[cos(omega), -sin(omega); sin(omega), cos(omega)];
b = [0;1];
c = sigma*[-cos(omega); sin(omega)];
%zero response, so intial state is 0
state = [0;0];
for i=1:length(in)
	out(i) = c'*state;
	state = M*state + b*in(i);
end
