To provide a driver alert system capable of improving the safety. A bicycle includes a first transmission circuit transmitting a first ultrasonic wave, a first receiving circuit receiving a second ultrasonic wave, an arithmetic circuit detecting the presence or absence of an object from the second ultrasonic wave, and a second transmission circuit transmitting a third ultrasonic wave. A driver wears a second housing including a second receiving circuit receiving the third ultrasonic wave. The arithmetic circuit includes a first selection circuit selecting a potential based on the second ultrasonic wave at a different timing, a plurality of signal retention circuits retaining a potential based on the second ultrasonic wave, a second selection circuit selecting any one of the plurality of signal retention circuits, and a signal processing circuit to which a signal selected in and output from the second selection circuit is input. The second selection circuit selects the plurality of signal retention circuits at different timings to generate a signal obtained by delaying the second ultrasonic wave. The third ultrasonic wave generated on the basis of the signal is transmitted to the second housing.

A detection system includes: a detection portion that has an output function outputting a detection wave toward surroundings of a vehicle, and a detection function detecting an object around the vehicle based on a reflected wave; a determination section that determines that the object is definitely present around the vehicle when a number of times of detection of the object by the detection function exceeds a predetermined number of times; a control section that causes operation of the detection function without operation of the output function when the vehicle travels at a predetermined speed or higher; and an adjustment section that adjusts and increases the predetermined number of times designated for the determination section when the object is detected by the detection function operated by the control section during traveling of the vehicle at the predetermined speed or higher.

A detection system includes: a detection portion that has an output function outputting a detection wave toward surroundings of a vehicle, and a detection function detecting an object around the vehicle based on a reflected wave; a determination section that determines that the object is definitely present around the vehicle when a number of times of detection of the object by the detection function exceeds a predetermined number of times; a control section that causes operation of the detection function without operation of the output function when the vehicle travels at a predetermined speed or higher; and an adjustment section that adjusts and increases the predetermined number of times designated for the determination section when the object is detected by the detection function operated by the control section during traveling of the vehicle at the predetermined speed or higher.

An ultrasonic sensor includes a first electrode, a second electrode, and a third electrode. The first electrode is provided an ultrasonic microphone that includes a vibration element that provides a function for converting between mechanical vibrations and electrical signals. The second electrode is externally from the ultrasonic microphone such that an electrical characteristic between the second electrode and the first electrode changes based on an adhesion state of substances adhering to the ultrasonic microphone. The third electrode is provided so as to suppress changes in the electrical characteristic between the first electrode and the second electrode caused by factors other than the adhesion of substances adhering to the ultrasonic microphone.

A sonar system and method enable performing angled-looking sonar (ALS) by emitting sonar waves in a forward and downward direction from sonar transducers located at an underwater vessel. The sonar waves may be received by sonar transducers located at the underwater vessel. Additionally, a variable geometry sonar system and method enable performing ALS by moving at least one sonar transducer to perform ALS. A centerline detection algorithm for ALS may be based on measured sonar data using A-scan crossing detection between port and starboard arrays. Once the centerline has been precisely located, subsequent ALS sonar images can be accurately mapped together.

A sonar system and method enable performing angled-looking sonar (ALS) by emitting sonar waves in a forward and downward direction from sonar transducers located at an underwater vessel. The sonar waves may be received by sonar transducers located at the underwater vessel. Additionally, a variable geometry sonar system and method enable performing ALS by moving at least one sonar transducer to perform ALS. A centerline detection algorithm for ALS may be based on measured sonar data using A-scan crossing detection between port and starboard arrays. Once the centerline has been precisely located, subsequent ALS sonar images can be accurately mapped together.

An ultrasonic transmitter system includes a digital controller, bandpass pulse-width modulator (BP-PWM) unit, a digital to analog converter (DAC), and an ultrasound transducer. The controller generates pulse width and phase reference signals. The BP-PWM configured receives these signals generates a pulse width modulation (PWM) output characterized by a pulse width and a phase based on the pulse width and phase reference signals. The DAC) receives the PWM output from the BP-PWM unit and generates an output characterized by the pulse width and phase. The ultrasonic transducer receives the output from the DAC and generates an output sound pressure in response to the output from the DAC. An amplitude of the RMS sound pressure depends on the pulse width of the output from the DAC.

An ultrasonic transmitter system includes a digital controller, bandpass pulse-width modulator (BP-PWM) unit, a digital to analog converter (DAC), and an ultrasound transducer. The controller generates pulse width and phase reference signals. The BP-PWM configured receives these signals generates a pulse width modulation (PWM) output characterized by a pulse width and a phase based on the pulse width and phase reference signals. The DAC) receives the PWM output from the BP-PWM unit and generates an output characterized by the pulse width and phase. The ultrasonic transducer receives the output from the DAC and generates an output sound pressure in response to the output from the DAC. An amplitude of the RMS sound pressure depends on the pulse width of the output from the DAC.

A marine multibeam sonar device comprises a processing element and a transmitter. The processing element generates a plurality of transmit transducer electronic signals and inverts a polarity of a first portion of the transmit transducer electronic signals. The transmitter is in communication with the processing element and includes a plurality of transmit electronic circuits and a plurality of transmit transducers. Each transmit electronic circuit receives and processes one of the transmit transducer electronic signals, wherein a first portion of the circuits re-inverts the polarity of the first portion of the transmit transducer electronic signals. The transmit transducers receive the processed transmit transducer electronic signals from the transmit electronic circuits and generate a sonar beam.

A marine multibeam sonar device comprises a processing element and a transmitter. The processing element generates a plurality of transmit transducer electronic signals and inverts a polarity of a first portion of the transmit transducer electronic signals. The transmitter is in communication with the processing element and includes a plurality of transmit electronic circuits and a plurality of transmit transducers. Each transmit electronic circuit receives and processes one of the transmit transducer electronic signals, wherein a first portion of the circuits re-inverts the polarity of the first portion of the transmit transducer electronic signals. The transmit transducers receive the processed transmit transducer electronic signals from the transmit electronic circuits and generate a sonar beam.