| 摘要 |
PURPOSE: A loss prevention circuit of portable apparatus is provided to efficiently prevent the loss of portable apparatus by using a correlation of the pseudo random number sequence. CONSTITUTION: The loss prevention circuit of portable apparatus consists of a transmission block and a loss prevention sensing circuit. The loss prevention sensing circuit comprises an A/D conversion block(31), a sample selection block(32), the first multiplication block(34), an addition block(35), a threshold comparison block(36) and an external output device(37). The transmission system comprises the second multiplication block(39), a D/A conversion block(40) and a RF transmission block(41), which are installed in the portable apparatus. Thereby, it is possible to simplify the system configuration without the necessity of a block to decode the activation signal by using the correlative characteristic of PN sequence, and to allocate a unique activation signal source to discriminate individual user.
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