| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultrasonic acoustic apparatus which is constituted of only general components, thereby attaining reduction of costs, the apparatus having a frequency modulator, a preamplifier, a power amplifier and an ultrasonic transmitter. SOLUTION: During driving pulse voltage generation to generate a driving pulse voltage for transmitting an ultrasonic wave from an ultrasonic transmitter in a case where, e.g., an audio signal is inputted to an input, an ultrasonic acoustic apparatus inputs an AC signal based on the audio signal, varies a term for determining ON/OFF of a driving pulse to frequency-modulate the driving pulse voltage, and transmits the ultrasonic wave from the ultrasonic transmitter with the frequency-modulated driving pulse voltage. The functions can be easily achieved by using a general timer, a general logic, a general transistor and a general FET (Field Effect Transistor). COPYRIGHT: (C)2009,JPO&INPIT
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