| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve security of a communication system. <P>SOLUTION: The phases of both phase signals are set to be mutually different. Herein, the unlock of a vehicle door may be executed by using a relay to establish an improper communication between an on-vehicle device 20 and an electronic key 10 located far away from each other. When relaying LF-band radio signals, the relay detects the received radio signals once and, based on its detected signals, creates and transmits radio signals having higher-intensity radio waves. In this case, the phases of both phase signals, which are mutually different, become the same phase during envelope detection of the received radio signals (the phase signals). Thus, when using the relay for the improper communication, the determination that the phases of both phase signals are not different is made to restrict the unlock of the vehicle door. <P>COPYRIGHT: (C)2013,JPO&INPIT |
