| 摘要 |
A personnel identification system for controlling access to restricted equipment or restricted areas comprises a portable device such as a wrist watch (10) in which a unique digital identification code is stored, and a static control unit having a conductive touch element (12) and a code signal receiver (14) for comparing the identification code with a stored access code. The watch (10) includes a transmitter for transmitting the identification code as a modulated alternating signal by electrical conduction through the wearer's body to the touch element (12), so as to provide resistance to interfering radiated signals. The receiver includes a separate touch sensing circuit for sensing physical contact on the element (12) so that decoding circuitry in the receiver is activated only when contact is sensed thereby enhancing resistance to radiated signals and substantially ensuring that the identification code signal is received at sufficient strength, given the power restrictions of a battery operated portable device, for reliable detection and validation of the identification code. <IMAGE>
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