| 摘要 |
PROBLEM TO BE SOLVED: To efficiently obtain a vibration output at a resonance peak frequency of an electro-mechanmical-acoustic transducers itself in a stable manner without needing to adjust the level of a drive signal every transducer. SOLUTION: There are provided an automatic level control circuit having a detection circuit which detects the level of a signal outputted as a drive signal to output a control signal, and a voltage control type amplifying circuit which amplifies and outputs an input signal received based on the control signal from the detection circuit, a limiter circuit to limit the level of the output signal of the automatic level control circuit within a predetermined range, and a first filter means which receives the output signal limited by the limiter circuit and removes from the output signal at least a frequency component equal to or higher than a second higher harmonic component of a resonance peak frequency of the electro-mechanial-acoustic transducer to output it as a drive signal. |
