Piezoelectric performance is improved in a piezoelectric ceramic having a perovskite-type crystal structure expressed by a general formula ABO3 and the B-site element including niobium. One of the plurality of fuse units electrically connects one of the first electrodes and the supporting electrode. Preferably, the encoded data estimator, the pair of ICI estimators, and the pair of diversity combining equalizers are implemented on a DVB-TH diversity SoC. The data packet portions are separated by a variable interval to prevent collisions of transmissions at the receiver. The board receiver and the engagement member clamp the frame of the control key unit in a second direction of the frame therebetween. The alternating current output of the bridge circuit is connected to the primary winding and a rectifier bridge with diodes to the secondary winding.