The Toeplitz Jacobian matrix method is an efficient algorithm for comp
uting the steady state solutions of nonlinear periodic vibration. In t
his paper the method is generalized by using multiple time scales to d
ouble-periodic solutions in a multi-frequency excited system. The meth
od is combined with a standard multi-dimensional FFT algorithm to accu
rately simulate the nonlinear oscillators with widely separated freque
ncies. The continuation technique can also be incorporated with the Ne
wton-Raphson iteration to further increase its efficiency and to achie
ve the complete frequency response characteristics.