s = tf('s') omega_n = 1 %zeta = 0.3 zeta = 0.1 G2_tf = omega_n^2 / (s^2 + 2*zeta*omega_n*s + omega_n^2) A = [0, 1; -omega_n^2, -2*zeta*omega_n] B = [0; 1] C = [omega_n^2, 0] D = 0 G2_ss = ss(A, B, C, D) bode(G2_tf, 'b', G2_ss, 'r--');