Abstract: A high-frequency amplifier has a semiconductor element for amplifying a high-frequency signal, an input matching circuit connected to an input side of the semiconductor element, and an output matching circuit connected to an output side of the semiconductor element. A stabilizing circuit is connected to at least one of a signal input path between the input matching circuit and the semiconductor element, and a signal output path between the semiconductor element and the output matching circuit. The stabilizing circuit includes a first element having a first end which is short-circuited with respect to a high frequency, a parallel resonant circuit connected in series with a second end of the first element and performing parallel resonance at an operating frequency of the high-frequency amplifier, and a second element connected to a side of the parallel resonant circuit which is opposite to the first element.

Abstract: Series reactance elements constituted by capacitors are connected to an input side corresponding to the gate electrode of an amplifying FET and an output side corresponding to the drain electrode of the amplifying FET, respectively. Parallel variable reactance circuits are connected to the input and output sides, respectively. Each variable reactance circuit includes a FET, where the source electrodes of the FET are connected to the input and output sides through MIM capacitors, respectively. Additionally, drain electrodes of the FETs are grounded through inductive loads which are constituted by spiral inductors, respectively. The source electrodes of the FETs constituting the variable reactance circuits are grounded through choke coils, respectively. The drain electrodes of the FETs receive control bias voltages through the choke coils, respectively.

Abstract: The invention relates to a transponder for a vehicle identification device in which a radio wave including vehicle information returned from transponders provided in a vehicle is received by an interrogator. The vehicle transponder receives a query radio wave and uses a detection device to generate a previously memorized coded signal train in response to a received wave. The coded signal train varies an amount of bias voltage of the detection device so that a reflection coefficient of the detection device is varied to modulate the reflection wave of the query radio wave and the modulated wave is transmitted back to the interrogator.

Abstract: A system for supplying energy to a microrobot disposed within a piping system for inspection or repair. The system comprises a microwave transmission section for transmitting as energy a microwave to the robot within the piping system. The microwave transmission section is arranged to transmit the microwave having a frequency equal to or higher than a frequency determined in correspondence with an inner diameter of a pipe of the piping system in which the microrobot is disposed. The microrobot receives the transmitted microwave to convert it into an electric power for operation. This arrangement can ensure a smooth operation of the microrobot within a small-sized pipe because the microrobot is not connected to the transmission section through an electric connection.

Abstract: A Doppler radar speed detecting method in which periods of a Doppler signal are measured within a predetermined sampling time, and frequency data corresponding to the thus obtained period data are obtained. Upper and lower limit values are set based on the previous Doppler frequency F(k-1). The frequency data are compared with these limit values. Frequency data within a low region lower than the lower limit value, and intermedaite region between the lower and upper limit values, and a high region higher than the upper limit value are respectively counted in accordance with the comparison. Further, for the frequency data between the lower and upper limits, an integrated value of differences between these data and the previous Doppler frequency is obtained. From these integrated value and the numbers of frequency data, the change from the previous to the present Doppler frequency is calculated. By adding this change and the previous Doppler frequency together, the present Doppler frequency is obtained.

Abstract: In a planar array antenna in which radio frequency power fed by a feeder line is radiated from a plurality of radiation elements disposed in a planar state on one surface of a dielectric substrate on the other surface of which the feeder line is disposed, the feeder line has a first feeder part and a second feeder part.

Abstract: A microwave probe has a cylindrical support made of stabilized zirconia being excellent in heat insulation, and the cylindrical support is threadably installed at a partitioning wall to partition an atmosphere of high temperature. The support is provided at the center with a through hole, and an antenna for transmitting or receiving microwave is installed at one opening of the through hole positioning at outside of the partitioning wall, and a metal ring member is installed at other opening of the through hole positioning within the partitioning wall. The transmitting and receiving antenna and the ring member are fixed to respective openings by a ceramic adhesive which is filled in the through hole and excellent in heat insulation. A part of the ring member projects in the atmosphere.

Abstract: An apparatus capable of sensing sudden approach of a succeeding vehicle and emitting an alarm, while being free from malfunction that may otherwise be caused by the noise from the succeeding vehicle which has approached at a normal speed and stopped in the proximity.

Abstract: A rear monitor system for an automotive vehicle comprises a sensor secured to a vehicle door located on one side of the vehicle and adapted to be operated by a vehicle occupant when leaving the vehicle, the sensor generating a signal indicating that the occupant is going to leave the vehicle. A control unit is responsive to the signal from the sensor for transmitting radiant energy in a rearward direction to detect a reflection from an object approaching the vehicle from behind at a speed higher than a predetermined value. Further provided is a safety device which is responsive to the detected reflection for preventing the vehicle occupant from opening the door.

Abstract: An ultrasonic transducer comprises a cylindrical housing embedded within a rear bumper of a vehicle and opening backward, a reflecting plate having a parabolic reflecting surface provided within the cylindrical housing along a closed end thereof and facing an open end thereof, and an ultrasonic vibrator provided in an upper wall of the housing at the focus of the reflecting plate for emitting and receiving ultrasonic waves. The ultrasonic transducer transmits ultrasonic waves behind the vehicle and receives ultrasonic waves reflected from an obstacle. The ultrasonic transducer further comprises a projecting member provided on the inner wall of the housing along the open end thereof for dispersing and cancelling the ultrasonic waves entering the housing at angles with respect to the axis of the housing. The projecting member has a smoothly curving cross section having a radius of substantially one fourth to five times the wavelength of the ultrasonic waves emitted by the ultrasonic vibrator.

Abstract: An apparatus for detecting obstructions behind a vehicle, employing ultrasonic waves is disclosed. The apparatus comprises an ultrasonic transmitting and receiving device disposed on the rear portion of the vehicle, an electric motor for rotating the transmitting and receiving device at a constant velocity, an angle sensor for detecting the rotating angle of the transmitting and receiving device and a sonar circuit for emitting ultrasonic waves through the transmitting and receiving device at predetermined rotating angles, receiving ultrasonic waves reflected from obstructions through the transmitting and receiving device at predetermined rotating angles and measuring the distance to the obstructions from the time taken from the transmission to the reception of the ultrasonic waves.

Abstract: A diesel smoke meter which uses micro-waves to detect the density of black smoke contained in the exhaust gas discharged from the diesel engine through an exhaust pipe. A micro-wave transmitting device is coupled to the exhaust pipe and transmits micro-waves into the exhaust pipe. Micro-waves transiting the exhaust pipe are attenuated by the black smoke in the exhaust gas. A micro-wave receiving device receives the attenuated micro-waves and provides a received signal which varies in accordance with the signal level of the attenuated micro-waves. A measuring device receives the received signal and provides an output indicative of the density of black smoke in the exhaust gas.

Abstract: A high frequency current inducing apparatus for inducing high frequency current in a wiring harness of an instrument to be examined without the necessity of detaching the wiring harness from the instrument. A high frequency current inducing chamber is connected to a high frequency oscillator for inducing the high frequency current in the wiring harness of the instrument to be inspected, and a terminator is connected to the high frequency inducing chamber. The chamber includes an outer conductor and an inner conductor fixed at a predetermined position inside the outer conductor. The outer conductor has two inserting holes for insertion of the wiring harness along the axis of the chamber between the two conductors. The outer conductor can be separated along a plane including the two inserting holes. Once separated, the wiring harness of the instrument to be inspected can be inserted along the axis of the chamber without detaching the wiring harness from the instrument.

Abstract: An obstacle monitoring device for the rear of a vehicle comprising a plurality of ultrasonic obstacle detectors which are operated sequentially at a predetermined time interval, and an electronic monitor for supplying the obstacle detectors with their operational timing sequences at the predetermined time intervals and for determining distance information for each detector based on the changing pulse width of electric currents for each of the obstacle detectors within a particular time interval, which pulse widths correspond to the distance between an obstacle and the rear of the vehicle. A single transmission line connects the obstacle detectors with the monitor so that the number of wires in a wire-harness is reduced between the obstacle detectors (outside the vehicle) and the monitor (inside the vehicle).

Abstract: An ultrasonic wave conversion apparatus comprises electrodes, a support member for supporting the electrodes, a vibrator secured to the support member by a securing member, and a moving diaphragm fixed to the vibrator by a fixing member. The surface of portions of the electrodes, the vibrator, the moving diaphragm and the fixing member are coated with an insulating film of a predetermined thickness. The coating with this insulating film provides the apparatus with an excellent insulating and anticorrosive property and further an excellent damping characteristic for the vibration of the vibrating members of the apparatus.

Abstract: Provided is an ultrasonic transducer having a resonator which defines a space together with a bimorph cell disposed in the ultrasonic transducer. The space is fluid-tightly closed by the top portion of the resonator, thereby to keep water, such as for example, rainwater or cleaning water from entering into the space.

Abstract: An automotive rear safety checking apparatus which comprises a plurality of obstacle detectors mounted on the rear part of the automobile for radiating ultrasonic wave on the watching areas smaller in width than the width of the automobile respectively and detecting the ultrasonic wave reflected from an obstacle. The ultrasonic wave is radiated from the obstacle detectors in time division. Pulse signals in the number associated with the distance between the obstacle detector and the obstacle are generated in response to the detection of the ultrasonic wave reflected from the obstacle, so that the relative positions of the automobile and the obstacle, are indicated two-dimensionally in accordance with the pulse signal.

Abstract: An ultrasonic transmitting and receiving device comprises a bimorph vibrator including two piezoelectric elements each connected electrically to the corresponding one of a plurality of terminals for receiving and delivering electric signals and a metallic member made of a thin metal plate and including a flat plate portion and a cylindrical portion extending from the circumferential periphery of the flat plate portion. The flat plate portion is placed between the piezoelectric elements and the cylindrical portion increases in outer diameter as it becomes distant from the flat plate portion.

Abstract: In an ultrasonic wave distance detection system, an ultrasonic wave pulse radiated into the selected area is reflected on an object. Said reflected ultrasonic wave pulse is partly received by an ultrasonic wave transducer. The received signal is supplied to a variable gain amplifier, noise components are removed from the amplified signal through a band pass filter, the noise removed signal is detected by an envelope detector, the detected signal is compared with a predetermined level by a comparator, and the output of the comparator is applied to a flip-flop circuit.As the gain of the variable gain amplifier is set to be a lower level only at the beginning of the ultrasonic wave pulse to minimize the amplification of unnecessary signals without reducing the detection efficiency, a signal can be surely obtained which has a pulse width corresponding to the distance between the system and the object and thus the distance can be detected or measured.

Abstract: An ultrasonic wave transmitter and receiver adapted to be mounted on the rear portion of a vehicle to detect the distance between the rear end of the vehicle and any obstruction located at the rear side of the vehicle. The ultrasonic wave transmitter and receiver includes an ultrasonic transducer attached to a lower part of the vehicle at a portion spaced from the rear end of the vehicle in the forward direction of the vehicle by a predetermined distance, a horn opening rearwardly from the vehicle and a wave guide tube through which the horn and the ultrasonic transducer are coupled to each other. The distance between the ultrasonic transducer and the rear end of the vehicle is selected to correspond to a time length which is long enough to sufficiently attenuate the residual oscillation of the ultrasonic transducer.