Abstract: A remote operation system includes responders that detect the pressure of tires of a vehicle, an interrogator that is provided in a main body of the vehicle and communicates with the responders so as to process pressure data, a plurality of antennas that are provided in the vicinities of the tires, respectively, and are connected to the interrogator, and a portable transmitter for a remote operation that communicates with the interrogator and unlocks the doors of the vehicle. The interrogator has a reception intensity detector that detects an intensity of a received signal from the transmitter received by each antenna. When each antenna receives an unlock signal to be transmitted from the transmitter, a door closest to one of the antennas which receives a signal having the highest reception intensity is unlocked.

Abstract: An interrogator includes a first oscillator for outputting a first signal and a second oscillator for outputting a second signal, a power synthesis distributing circuit for synthesizing the first and second signals, an antenna which is coupled to a synthesis terminal of the power synthesis distributing circuit, a first mixer unit interposed between one distribution terminal of the power synthesis distributing circuit and the first oscillator, and a first switching unit which connects the other distribution terminal of the power synthesis distributing circuit to the one distributing terminal or the second oscillator. The other distribution terminal is connected to the second oscillator by the first switching unit during a transmitting period, and the other distribution terminal is connected to the first mixer unit during a receiving period.

Abstract: An apparatus for sensing tire information including information about tire pressure includes an interrogator for transmitting an interrogation signal to a vicinity of a tire of a vehicle in a transmission period and for receiving and processing a response signal including the tire information in a reception period and a transponder attached to the tire. The transponder includes a sensor for sensing the tire information and a second mixing unit for mixing first and second signals and outputting a difference signal having a frequency equal to a difference in frequency between the first and second signals. The interrogator includes a power combining circuit for combining the first and second signals. The first signal is different from the second signal by a predetermined frequency that can excite the sensor. In the transmission period, a combined signal of the first and second signals is transmitted from an antenna of the interrogator.

Abstract: An apparatus for sensing tire information including information about tire pressure includes an interrogator for transmitting an interrogation signal to a vicinity of a tire of a vehicle in a transmission period and for receiving and processing a response signal including the tire information in a reception period and a transponder attached to the tire. The transponder includes a sensor sensing the tire information and a second mixing unit for mixing first and second signals and outputting a difference signal having a frequency equal to a difference in frequency between the first and second signals. In the transmission period, a second antenna is connected to a second oscillator by a first switching unit, and the first and second signals are transmitted from a first antenna and the second antenna of the interrogator. The first signal is different from the second signal by a predetermined frequency that can excite the sensor.

Abstract: A remote operation system includes responders that detects the pressure of tires of a vehicle, an interrogator that is provided in a main body of the vehicle and communicates with the responders so as to process pressure data, a plurality of antennas that are provided in the vicinities of the tires, respectively, and are connected to the interrogator, and a portable transmitter for a remote operation that communicates with the interrogator and unlocks the doors of the vehicle. The interrogator has a reception intensity detector that detects an intensity of a received signal from the transmitter received by each antenna. When each antenna receives an unlock signal to be transmitted from the transmitter, a door closest to one of the antennas which receives a signal having the highest reception intensity is unlocked.