[G, J, handle] = levy (w, gain, phase, Q, n, m) This function returns a model for a plant with a known frequency behaviour. The model is b(1)*s^(m*Q) + b(2)*s^((m-1)Q) + ... + b(end-2)*s^(2*Q) + b(end-1)*s^Q + b(end) ------------------------------------------------------------------------------- a(1)*s^(n*Q) + a(2)*s^((n-1)Q) + ... + a(end-2)*s^(2*Q) + a(end-1)*s^Q + a(end) The function receives the gain in dB and the phase in degrees for frequencies, in rad/s, specified in w. Parameters Q, n and m must be supplid; a structure is returned with fields num and den, containing vectors b and a respectively. J is the quadratic error per sampling frequency. If the last output argument exists, a handle for a Bode plot will be returned. Duarte Valério 2003