| 摘要 |
PROBLEM TO BE SOLVED: To discriminate the genuineness of electronic equipment by building up an authentication device in a mobile telephone set, etc., giving a specific input signal code to the authentication device when using it or supplying the power to it and returning the output that only the a genuine authentication device knows to a host computer. SOLUTION: The authentication device 10 which is built up in electronic equipment such as a portable telephone set has a piezoelectric body 11 made of a piezoelectric material, and an input side inter-digital electrode 12 and an output side inter-digital electrode 30 which are provided on the piezoelectric body 11. When a high-frequency input signal 21 which is modulated by a pulse train presenting a specific input signal code 20 is inputted, the input side inter-digital electrode 12 allows the piezoelectric body 11 to generate a surface acoustic wave which corresponds to the pulse train. The output side inter-digital electrode 30 has pairs 33 of electrodes. A specific electrode code pattern 40 is constituted by optionally combining electrode fingers 31 and 32 (polarity) of each electrode pair 33. For the usage of the electronic appliance, the high-frequency input signal 21 is inputted to the input side inter-digital electrode 12 and this electronic appliance is judged to be genuine on condition that the output signal 50 outputted by the output side inter-digital electrode 30 corresponds to data for collating that the host prepares.
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