| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an entry system capable of easily measuring propagation delay time of radio waves upon detection of distance between the entry system and a portable transceiver and changing for a remote control system. SOLUTION: A keyless-entry system is equipped with a door side radio equipment 30 having devices 31, 32 and 33 for examining justification of an answer signal receiving from the air based on an identifier contained therein after a call signal requiring transmission of the answer signal, the device 31 for detecting distance between the entry system and a transmitter of the answer signal based on time difference from transmission of the call signal mentioned above to reception of the answer signal mentioned above and devices 31 and 34 transmitting radio waves, rays or ultrasonic waves modulated by a command related to locking or unlocking of a door according to whether the detected distance mentioned above is less than specific value or not when the answer signal mentioned above is justified, a portable type transceiver 20 receiving the call signal mentioned above and transmitting the answer signal containing the identifier mentioned above in the air and a locking and unlocking execution section 10 receiving radio waves, rays or ultrasonic waves transmitted from the door side radio equipment 30 to execute the command by demodulating the command related to locking or unlocking of the door.</p> |
