Abstract: A mobile device includes a signal generating unit that generates a first signal and a transmitting unit that wirelessly transmits the first signal generated by the signal generating unit. The first signal includes frequency information that is used in wireless communication between the mobile device and a tuner. The tuner includes a setting processing unit that sets a receiving frequency of an antenna and a demodulation frequency of a phase synchronization circuit. The setting processing unit sets the receiving frequency and the demodulation frequency on the basis of the frequency information included in the first signal from the mobile device.

Abstract: A mobile device includes a signal generating unit that generates a first signal and a transmitting unit that wirelessly transmits the first signal generated by the signal generating unit. The first signal includes frequency information that is used in wireless communication between the mobile device and a tuner. The tuner includes a setting processing unit that sets a receiving frequency of an antenna and a demodulation frequency of a phase synchronization circuit. The setting processing unit sets the receiving frequency and the demodulation frequency on the basis of the frequency information included in the first signal from the mobile device.

Abstract: In a wireless communication apparatus, when a first switch electrically connects a second antenna to an impedance matching circuit and a second switch electrically connects a first antenna to a reception circuit, a frequency signal output from an oscillator of the reception circuit is received by the second antenna and applied to the impedance matching circuit. Then, a controller controls the impedance of the impedance matching circuit so as to bring a RSSI voltage output from a signal strength detection circuit of the reception circuit into agreement with a reference RSSI voltage, thereby bringing the reference frequency of the first antenna into agreement with a reference frequency.

Abstract: A matching circuit, connected to a receiving antenna and to the input of a receiving circuit, incorporates a variable capacitor that is adjustable for tuning the resonance frequency of the antenna to a desired reception frequency. In an automatic tuning mode of operation, an oscillator signal of different frequency from the reception frequency is applied to induce resonance of the antenna and matching circuit, and the variable capacitor is adjusted until an output signal level from the receiving circuit attains a predetermined value which has been stored beforehand in a memory and which corresponds to a condition whereby the antenna resonance frequency corresponds to the reception frequency and impedance matching exists between the antenna and receiving circuit.

Abstract: In a wireless communication apparatus, when a first switch electrically connects a second antenna to an impedance matching circuit and a second switch electrically connects a first antenna to a reception circuit, a frequency signal output from an oscillator of the reception circuit is received by the second antenna and applied to the impedance matching circuit. Then, a controller controls the impedance of the impedance matching circuit so as to bring a RSSI voltage output from a signal strength detection circuit of the reception circuit into agreement with a reference RSSI voltage, thereby bringing the reference frequency of the first antenna into agreement with a reference frequency.

Abstract: A matching circuit, connected to a receiving antenna and to the input of a receiving circuit, incorporates a variable capacitor that is adjustable for tuning the resonance frequency of the antenna to a desired reception frequency. In an automatic tuning mode of operation, an oscillator signal of different frequency from the reception frequency is applied to induce resonance of the antenna and matching circuit, and the variable capacitor is adjusted until an output signal level from the receiving circuit attains a predetermined value which has been stored beforehand in a memory and which corresponds to a condition whereby the antenna resonance frequency corresponds to the reception frequency and impedance matching exists between the antenna and receiving circuit.

Abstract: An electronic key system includes an in-vehicle unit mounted in a vehicle and a portable unit. When a user leaves the vehicle, the in-vehicle unit requests information on a relative position of the vehicle relative to a landmark object near the vehicle from a vehicle navigation device and transmits received relative position information to the portable unit. The portable unit stores the received relative position information, and notifies of the stored relative position information according to a user's operation.