Transient responses and stationary processes with alternating fields are treated in the nonlinear regime in order to clarify their relations in the time and frequency domains. It is shown that a frequency-domain experiment in which a weak ac field is superimposed on a strong biasing dc field corresponds to the transient process of a strong constant biasing field with the sudden application of weak constant field. Furthermore, it is found that the Fourier-Laplace transform of the second-order nonlinear transient rise process corresponds to the amplitude for the \ensuremath{\omega} component of the stationary experiment with coupled dc and ac fields with the angular frequency \ensuremath{\omega}. For a simple ac input, we demonstrated how the stationary nonlinear response may conveniently be calculated with the help of the theory of random walk. Also, interrelations among the rise, decay, and rapidly re- versing transients are clarified.