A back plate having a recess in an underside thereof and a stationary back electrode at a central portion thereof is secured to a substrate, a spacer having an opening is mounted on the back plate so as to form a vacancy between an inside wall of the opening and a periphery of the stationary back electrode. Placing a magnetomechanical resonator into the cavity and sealing a cover onto the cavity layer wherein the resonator is captured in the cavity and free to mechanically vibrate substantially unencumbered. In the positioning type servo amplifier 30 and the command follow-up type servo amplifier 50, there is provided information reading section for reading the content of an information section after the discrimination data of the command frame 100 by the discrimination data of the command frame 100.