Abstract: A tire information detecting apparatus includes an interrogator which transmits an interrogation signal toward a tire in a vehicle at a transmitting timing, and receives a reply signal including tire information at a receiving timing so as to process the signals. A responder is disposed in the tire and has a sensor excited by a predetermined frequency signal for detecting tire information so as to return the reply signal to the interrogator at the receiving timing in responding to the interrogation signal. A mixer unit receives the interrogation signal having a first signal and a second signal which is spaced the predetermined frequency away from the first signal, from the interrogator, and outputs a signal of the frequency difference between the two signals to the responder by mixing the first and second signals.

Abstract: An OFDM receiver has four antennas or more for receiving an OFDM modulated high frequency signal, and plural OFDM demodulators for inputting a baseband signal of a time domain thereto on the basis of the high frequency signal and outputting the baseband signal of a frequency domain, wherein the OFDM demodulators are arranged every plural antenna groups with two or more of the antennas as one group, and a signal is diversity-synthesized by a first phase shifter until the baseband signal of the time domain is inputted to each of the OFDM demodulators, and the baseband signal of the frequency domain is diversity-synthesized by a second phase shifter.

Abstract: An interrogator is disposed in a main body of a vehicle for transmitting interrogating signals. A responder is mounted to each tire of the vehicle for returning tire information such as air pressure to the interrogator in response to the interrogating signals. The responder is provided with at least one sensor for detecting tire information and a sensor specifying means for specifying properties of the sensor. The interrogator is provided with a control means for processing tire information, and correction tables for correcting properties of a sensor specified by the sensor specifying means. The control means corrects the tire information by the correction tables and then outputs data related to the tire information.

Abstract: A tire information detecting apparatus includes an interrogator which transmits an interrogation signal toward a tire in a vehicle at a transmitting timing, and receives a reply signal including tire information at a receiving timing so as to process the signals. A responder is disposed in the tire and has a sensor excited by a predetermined frequency signal for detecting tire information so as to return the reply signal to the interrogator at the receiving timing in responding to the interrogation signal. A mixer unit which receives the interrogation signal having a first signal and a second signal which is spaced the predetermined frequency away from the first signal, from the interrogator, and outputs a signal of the frequency difference between the two signals to the responder by mixing the first and second signals.

Abstract: A tire information detecting apparatus includes an interrogator provided to the main body of a vehicle and each of the responders provided to each of the tires of the vehicle and responding to the interrogator. Each of antenna units having an antenna, a mixer, and a branching filter is provided in the vicinity of each of the tires and is connected to the interrogator via cables. The mixer includes an interactive mixer, which has a first port and a second port connected interactively with each other, and a third port. The first port of the mixer is connected to the antenna, the second port is connected to the high frequency side port of the branching filter, the third port is connected to the low frequency side port of the branching filter, and a common port of the branching filter is connected to the cables.

Abstract: An interrogator is disposed in a main body of a vehicle for transmitting interrogating signals. A responder is mounted to each tire of the vehicle for returning tire information such as air pressure to the interrogator in response to the interrogating signals. The responder is provided with at least one sensor for detecting tire information and a sensor specifying means for specifying properties of the sensor. The interrogator is provided with a control means for processing tire information, and correction tables for correcting properties of a sensor specified by the sensor specifying means. The control means corrects the tire information by the correction tables and then outputs data related to the tire information.

Abstract: A circularly polarized wave antenna is constructed such that the circularly polarized wave antenna has four flat plate-shaped dielectrics having the substantially same thickness vertically provided on a printed substrate and arranged in a square-cylinder shape as a whole, and four radiation conductors provided, on each outer wall surface of the flat plate-shaped dielectrics, inclined in a fixed direction, such that a lower end of each of the radiation conductors is electrically connected to the printed substrate and such that electric power is fed to the four radiation conductors in phase.

Abstract: An OFDM receiver has four antennas or more for receiving an OFDM modulated high frequency signal, and plural OFDM demodulators for inputting a base band signal of a time area thereto on the basis of the high frequency signal and outputting the base band signal of a frequency area, wherein the OFDM demodulators are arranged every plural antenna groups with two or more of the antennas as one group, and a signal is diversity-synthesized by a first phase shifter until the base band signal of the time area is inputted to each of the OFDM demodulators, and the base band signal of the frequency area is diversity-synthesized by a second phase shifter.

Abstract: A circularly polarized wave antenna is constructed such that the circularly polarized wave antenna has four flat plate-shaped dielectrics having the substantially same thickness vertically provided on a printed substrate and arranged in a square-cylinder shape as a whole, and four radiation conductors provided, on each outer wall surface of the flat plate-shaped dielectrics, inclined in a fixed direction, such that a lower end of each of the radiation conductors is electrically connected to the printed substrate and such that electric power is fed to the four radiation conductors in phase. Thereby, a mechanical orthogonal relationship of each radiation conductor is retained so that deterioration in the antenna characteristics and the poor connection resulting from external vibrations can be reduced, and also a required length of the radiation conductor can be shortened by a shortened wavelength due to the flat plate-shaped dielectric having high specific inductive capacity.

Abstract: The electronic device of the present invention comprises a chassis, a printed circuit board mounted to the chassis and having circuit patterns formed thereon and a protective element connected onto the circuit patterns which protective element is for attenuating a surge voltage, and screws for holding the printed circuit board on the chassis, wherein the protective element is connected to the chassis through any of the screws.

Abstract: A high frequency oscillator having an oscillation transistor connected to a resonant strip line unit consisting of a main strip line member and an auxiliary strip line member. The auxiliary strip line member is connected in parallel with or isolated from the main strip line member by a switch diode for switching the characteristic impedance of the strip line unit so as to generate a reception or transmission carrier wave output. A varactor diode connected to the strip line unit has its capacitance changed through an applied control voltage for channel switching. A modulating signal input terminal is directly connected to a portion of the auxiliary strip line member for modulating an FM transmission signal independently of the value of the control voltage applied to the varactor diode.