Abstract: A standing wave radar includes: a transmitter to set a frequency of a transmission signal to frequencies, and output the transmission signal taking the respective frequencies in a time-division manner; a receiver to receive a reflected signal taking the frequencies in a time-division manner, the reflected signal being the transmission signal reflected by an object; and a processor to obtain reflection coefficients of the frequencies by obtaining each reflection coefficient of the transmission signal and the reflected signal taking a same frequency, for the transmission signal and the reflected signal taking the frequencies, and to execute a first inverse Fourier transform process of calculating a first distance spectrum for the object by an inverse Fourier transform on the reflection coefficients, and a first distance measurement process of determining presence of the object and calculating a distance to the object, based on the first distance spectrum.

Abstract: An information collection system includes a sensor terminal group including first sensor terminals and second sensor terminals and an information collection terminal capable of wireless communication with the sensor terminals. The information collection terminal includes a transmission unit that transmits data requests to the sensor terminals and a receiving unit that executes processing of receiving measurement data from the first sensor terminals in a first period, executes processing of receiving reception requests from the second sensor terminals in a second period, and when the reception requests are given, executes processing of receiving measurement data from the second sensor terminals in a third period. The second sensor terminal includes a transmission unit that, when the data requests are given, and when the control unit determines to transmit the measurement data, transmits the reception requests in the second period and transmits the measurement data in the third period.

Abstract: An information collection system includes a sensor terminal group including first sensor terminals and second sensor terminals and an information collection terminal capable of wireless communication with the sensor terminals. The information collection terminal includes a transmission unit that transmits data requests to the sensor terminals and a receiving unit that executes processing of receiving measurement data from the first sensor terminals in a first period, executes processing of receiving reception requests from the second sensor terminals in a second period, and when the reception requests are given, executes processing of receiving measurement data from the second sensor terminals in a third period. The second sensor terminal includes a transmission unit that, when the data requests are given, and when the control unit determines to transmit the measurement data, transmits the reception requests in the second period and transmits the measurement data in the third period.

Abstract: A seat belt wearing detection device includes: a tongue unit supported by a seat belt; a buckle unit into which the tongue unit is inserted and held; a wearing detection unit that detects an insertion and holding state; a seat belt side communication unit that transmits a detection result; a control unit that determines a wearing state based on the detection result and controls the seat belt side communication unit; power supply means for supplying electric power to the seat belt side communication unit; and a vehicle side device that performs radio communication with the seat belt side communication unit to receive the detection result. The power supply means includes a power supply section, a power storage section, and a charging section. The power supply section charges the power storage section by supplying electric power to the charging section when the seat belt is in a housed state.

Abstract: A seat belt wearing detection device includes: a tongue unit supported by a seat belt; a buckle unit into which the tongue unit is inserted and held; a wearing detection unit that detects an insertion and holding state; a seat belt side communication unit that transmits a detection result; a control unit that determines a wearing state based on the detection result and controls the seat belt side communication unit; power supply means for supplying electric power to the seat belt side communication unit; and a vehicle side device that performs radio communication with the seat belt side communication unit to receive the detection result. The power supply means includes a power supply section, a power storage section, and a charging section. The power supply section charges the power storage section by supplying electric power to the charging section when the seat belt is in a housed state.

Abstract: A vehicle includes a vehicle side device having a vehicle side transmitting-receiving section performing wireless communicating with a seat belt side and a control section (determination section) determining an installation state, based on a signal from the seat belt side; and a seat belt side device having a seat belt side transmitting-receiving section performing wireless communicating with the vehicle side, a first switching unit of which switches the state according to detaching and installing of the seat belt and an output unit which outputs a detaching-installing signal to the seat belt side transmitting-receiving section in response to the state of the first switching unit. A power is fed to the seat belt side transmitting-receiving section and the output unit, and the signal is output and transmitted by the signal form the vehicle side transmitting-receiving section.

Abstract: A vehicle includes a vehicle side device having a vehicle side transmitting-receiving section performing wireless communicating with a seat belt side and a control section (determination section) determining an installation state, based on a signal from the seat belt side; and a seat belt side device having a seat belt side transmitting-receiving section performing wireless communicating with the vehicle side, a first switching unit of which switches the state according to detaching and installing of the seat belt and an output unit which outputs a detaching-installing signal to the seat belt side transmitting-receiving section in response to the state of the first switching unit. A power is fed to the seat belt side transmitting-receiving section and the output unit, and the signal is output and transmitted by the signal form the vehicle side transmitting-receiving section.

Abstract: There is provided a tire information detector to promptly and accurately detect tire information such as pressure of a tire. The tire information detector includes a transponder including a resonator and disposed in a tire of a vehicle; and a controller disposed in a vehicle body, transmitting an excitation signal allowing the resonator to resonate to the transponder, receiving a resonance signal concerning a resonance frequency of the resonator, and calculating a measurement value in accordance with the resonance frequency of the resonator. The controller determines a frequency of the excitation signal based on the resonance frequency of the resonator obtained from previous communications with the transponder.

Abstract: A tire information detecting apparatus comprises a transponder that is provided in a tire of a vehicle and a controller that is provided in a vehicle body. The transponder comprises an antenna; a modem (modulator/demodulator) that modulates or demodulates signals transmitted between the transponder and the controller; a resonator that resonates in response to a signal transmitted from the controller; a pressure sensor that detects the air pressure of the tire; and a switch that connects or disconnects the crystal resonator to or from the pressure sensor.

Abstract: There is provided a tire information detector to promptly and accurately detect tire information such as pressure of a tire. The tire information detector includes a transponder including a resonator and disposed in a tire of a vehicle; and a controller disposed in a vehicle body, transmitting an excitation signal allowing the resonator to resonate to the transponder, receiving a resonance signal concerning a resonance frequency of the resonator, and calculating a measurement value in accordance with the resonance frequency of the resonator. The controller determines a frequency of the excitation signal based on the resonance frequency of the resonator obtained from previous communications with the transponder.

Abstract: A transponder is provided. The transponder includes an antenna, a modulation/demodulation unit (diode) that modulates and demodulates signals received and transmitted from and to a controller, a pressure resonator including a first piezoelectric single-crystal resonating element and a pressure sensor, and a reference resonator including a second piezoelectric single-crystal resonating element and a capacitor. The controller transmits a signal for resonating the pressure resonator and the reference resonator, receives a signal having the resonance frequency of the pressure resonator and a signal having the resonance frequency of the reference resonator, and computes a measured value in accordance with the resonance frequencies of the two resonators retrieved from the received signals.

Abstract: A tire information detecting device accurately detects tire pressure and temperature. The device includes a transponder mounted in a tire of a vehicle, and a controller located in the vehicle body. The transponder includes a diode, which modulates and demodulates a signal transmitted to and received from the controller, and a pressure measuring unit, which measures a tire pressure. Also included is a detecting resonance circuit connected between the diode and the pressure measuring unit, which resonates in accordance with a signal from the controller. A resonance circuit resonates in accordance with the signal from the controller and controls a connection between the pressure measuring unit and the detecting resonance circuit.

Abstract: A transponder includes an antenna, a modulation/demodulation unit (diode) that modulates and demodulates signals received and transmitted from and to a controller, a pressure resonator including a first piezoelectric single-crystal resonating element and a pressure sensor. The resonance frequency of the pressure resonator changes in accordance with a change in tire pressure, and a reference resonator includes a second piezoelectric single-crystal resonating element and a capacitor, where the resonance frequency of the reference resonator is unaffected by the change in tire pressure. The first and second piezoelectric single-crystal resonating elements are integrally formed on a single-crystal piece.

Abstract: A transponder is provided. The transponder includes an antenna, a modulation/demodulation unit (diode) that modulates and demodulates signals received and transmitted from and to a controller, a pressure resonator including a first piezoelectric single-crystal resonating element and a pressure sensor, and a reference resonator including a second piezoelectric single-crystal resonating element and a capacitor. The controller transmits a signal for resonating the pressure resonator and the reference resonator, receives a signal having the resonance frequency of the pressure resonator and a signal having the resonance frequency of the reference resonator, and computes a measured value in accordance with the resonance frequencies of the two resonators retrieved from the received signals.

Abstract: A system of detecting tire information includes a measured value transmitter that includes a first resonator with a pressure sensor and a second resonator without the pressure sensor, which are mounted in a tire of a vehicle. Also includes is a controller that is provided in the body of the vehicle, which transmits a signal used for resonance of the first and second resonators to the measured value transmitter, and receives signals associated with the resonant frequencies of the first and second resonators from the measured value transmitter, so as to calculate a measured value on the basis of the resonant frequencies of the first and second resonators. Characteristics of a piezoelectric single-crystal oscillator included in the first resonator are made closely analogous to those of a piezoelectric single-crystal oscillator included in the second resonator.

Abstract: A system of detecting tire information includes a measured value transmitter mounted in a tire of a vehicle and a controller provided in the body of the vehicle. The measured value transmitter includes an antenna, a resonator, the resonant frequency of which is varied in accordance with a temperature of the tire, and a resistive pressure sensor, the resistance of which is varied in accordance with a pressure in the tire. The controller transmits a signal for resonating the resonator and receives a signal having the resonant frequency of the resonator from the measured value transmitter. The controller calculates the temperature in the tire based on the signal having the resonant frequency. The controller calculates the pressure in the tire based on a signal level of the signal having the resonant frequency.

Abstract: A passive keyless entry device includes an in-vehicle transceiver and a portable transceiver. The in-vehicle transceiver has a clock signal generating circuit, a control signal generating signal that outputs a binary control signal having positive and negative values, a modulation circuit that forms a pulse modulation signal by modulating the clock signals by the control signal, and a transmission circuit that has half-bridge circuits, a low-frequency antenna being connected to output ends of the half-bridge circuits. The control signal changes from positive to negative value slightly later than the usual time. During a period from the usual time to the slightly later time, the clock signals modulated by the control signal are inverted clock signals that are shifted by half wavelength with respect to the usual clock signals.

Abstract: In an amplifying circuit for a transmitter including a first switching device having one end thereof connected to a power supply, a second switching device having one end thereof connected to another end of the first switching device and another end thereof grounded and an antenna connected to a junction point of the first switching device and the second switching device, wherein the first switching device and the second switching device 12 are alternately driven by a driver, the driver and a control electrode of the first switching device as well as the driver and a control electrode of the second switching device are connected through a common mode filter.

Abstract: A tire air pressure monitor includes tire air pressure sensors and transmitters proximate to tires; receiving antennas which receive transmitting signals from the transmitters; phase shifters which shift signal phases received from the antennas by control voltages; a synthesizer which synthesizes outputs from the phase shifters; and a meter which detects an output level from the synthesizer. The phase differences between the antennas are different and the control voltages for the phase shifters are obtained in advance, which maximizes the output level from the synthesizer dependent on the tire mounting positions. An association table relates the tire mounting positions to the control voltages and the control voltages are controlled so that the output level from the synthesizer is maximized with respect to a transmitting signal from any one of the tire mounting positions. The tire mounting positions is identified by comparing values of the control voltages thus controlled.

Abstract: A passive keyless entry device includes a fixed unit and a portable unit. A signal receiving section of the portable unit includes three antennas for receiving a signal which is wirelessly transmitted from the fixed unit with respect to three directions which are at right angles to one another; three amplifiers; three detectors; a selector circuit for selecting one detection output by which a wake-up signal can be detected and in which the received signal valve of the antenna is comparatively high from among the detection outputs which are output from the detectors; a level comparator; first and second switches; and a counter.