| 摘要 |
PROBLEM TO BE SOLVED: To provide a data transmission apparatus in which a wireless signal reducing dullness in rising and falling can be sent and a frequency-modulated wireless signal can also be sent in simple circuit configuration. SOLUTION: A data transmission apparatus comprises a transmission circuit section 2 which includes an oscillation circuit 21 of which an output frequency is variable, amplifies an output of the oscillation circuit 21 and outputs it as a transmission signal; an ultrasonic wave generating element 3 which is driven by a transmission signal from the transmission circuit section 2 to transmit an ultrasonic wave; and a transmission control section 4 which controls the output frequency of the oscillation circuit 21 to transmit, from the ultrasonic wave generating element 3, a wireless signal comprised of a frequency-modulated (e.g., FSK-modulated) ultrasonic wave. As the ultrasonic wave generating element 3, an element is used which gives thermal shock to air to generate an ultrasonic wave. COPYRIGHT: (C)2007,JPO&INPIT
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