  We demonstrate that a superoscillating in time signal may be obtained as a
nonlinear response on a harmonic low-frequency input. Using the realization of
a superoscillating function proposed by (Huang et al. 2007 J. Opt. A: Pure
Appl. Opt. 9 S285-8) as an example, we synthesize the response function of such
a nonlinear transformer and investigated its robustness with respect to the
frequency and amplitude variations of the input signal.
