| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a technology for increasing a transmission information amount, without having to extend the length of signal data to be transmitted. <P>SOLUTION: A first modulator 106 of a mobile unit 100 modulates a carrierαwith a control signal S1 including door lock/unlock information to produce a first modulated waveβ. Encryption information of the control signal S1 changes a time interval of pulses of the modulated waveβ. A second modulator 107 applies amplitude modulation to the modulated waveβby an ID signal S2 to produce a second modulated waveγ. That is, the modulation is applied to the carrier twice for its same period. The method above reduces the data length of the modulated wave. The mobile unit 100 wirelessly transmits the modulated waveγas a wireless response signal a. An on-vehicle unit 200 receives the response signal a, a detector 204 demodulates the door lock/unlock information included in the control signal S1, and a detector 206 demodulates the ID information included in the ID signal S2. The demodulated ID information and the demodulated door lock/unlock information are used to execute door lock/unlock control. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
