Piezoelectric ceramics can provide electromechanical transduction with high stresses but low displacements. To obtain larger displacements, several mechanical amplifying structures have been used. High alternating displacements can be obtained using resonant structures. We propose a displacement amplifier based on a mechanical rectifier, able to take advantage of the high displacements of resonant structures, and capable of obtaining a continuous displacement. A prototype composed of a Langevin resonator coupled to a mass–spring–damper system, acting as the rectifier, was constructed. Interferometric measurements on the proposed mechanical demodulator were carried out, validating the principle of operation. The possible applications are in the field of fast valves and micrometric positioning. © 1998 American Institute of Physics.