| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a communication system for a vehicle, which enables the easy construction of a communication environment suitable for a portable machine and an in-vehicle unit. <P>SOLUTION: An electronic key system 1 is equipped with the portable machine 10 with a radio communication function, and the in-vehicle unit 20 for controlling the vehicle 2 on the basis of radio communication with the portable machine 10. The in-vehicle unit 20 comprises a first transmission circuit 22 for transmitting a radio signal to a prescribed area around the vehicle 2, and a second transmission circuit 23 for transmitting the radio signal to a prescribed area in the cabin of the vehicle 2. The first transmission circuit 22 deviates the resonance frequency of a first transmission antenna 22a from the oscillating frequency of a first oscillating circuit so that the portable machine 10 can receive the radio signal from the first transmission circuit 22 in the prescribed area around the vehicle 2. The second transmission circuit 23 deviates the resonance frequency of a second transmission antenna 23a from the oscillating frequency of a second oscillating circuit so that the portable machine 10 can receive the radio signal from the second transmission circuit 23 in the prescribed area in the cabin of the vehicle 2. <P>COPYRIGHT: (C)2009,JPO&INPIT |
