| 摘要 |
A vehicle control system is provided to select one between a first radio signal and a second radio signal from a plurality of channels and to converting the selected signal into an intermediate frequency signal. A vehicle control system comprises a portable unit(2), a vehicle condition detector(3), and an in-vehicle receiver(4~6). The portable unit, which is carried by a user, transmits a first radio signal for a keyless entry system for remote-controlling equipment of the vehicle. The vehicle condition detector is mounted in the vehicle to transmit a second radio signal for a vehicle condition monitoring system. The in-vehicle receiver is mounted in the vehicle to receive the first radio signal and the second radio signal. The portable unit transmits the first radio signal through a plurality of channels different in frequency. The in-vehicle receiver includes a receiving antenna(20), a channel determining unit, a frequency conversion unit(28), and a demodulating unit(32), and a controlling unit(38). The receiving antenna is configured to receive the first radio signal and the second radio signal. The channel determining unit is configured to determine an optimal channel, which is in a most favorable state of communication, among the channels. The frequency conversion unit is configured to select either the first radio signal or the second radio signal in any of the channels from among signals received by the receiving antenna and convert the signal into an intermediate frequency signal of a specific frequency. The demodulating units for demodulating the intermediate frequency signal outputted from the frequency conversion circuit. The controlling unit is configured to cause the frequency conversion units to select the second radio signal when a demodulated signal of the second radio signal is to be acquired from the demodulating unit, and to cause the frequency conversion unit to select the first radio signal in the optimal channel determined by the channel determining unit when a demodulated signal of the first radio signal is to be acquired from the demodulating unit. |
