In a sonar system using a large array multielement sonar detector to detect reflected signals sent out by a sonar ping generator, the sent out sonar ping generator sends out varying frequency sonar signals during each ping, where the frequency is neither monotonically increasing or monotonically decreasing.

An ultrasonic sensor 1000 has a transmission/reception processing circuit 100, and the transmission/reception processing circuit 100 has a burst signal transmission circuit 1 that generates and transmits burst signals S0, and a signal processing circuit 7 that processes reception signals received by a piezoelectric element 4. The signal processing circuit 7 verifies the reverberation frequency of the reverberation signals of ultrasonic signals (reception signals) reflected to the piezoelectric element 4 from a subject, and on the basis of the verified reverberation frequency and reverberation time of the reception signals, adjusts the frequency of the burst signals S0 to be substantially equal to the reverberation frequency, said burst signals being to be generated by the burst signal transmission circuit 1.

A piezoelectric micro-machined ultrasonic transducer (PMUT) is provided, comprising a dedicated ultrasonic transmitter and at least one separate dedicated ultrasonic receiver on a single common semiconductor die. A plurality of PMUTs may be arranged in a tessellated array. Also disclosed is a system comprising at least one PMUT on a single common semiconductor die, a dedicated ultrasonic transmitter arranged to transmit a first ultrasonic signal and at least one separate dedicated ultrasonic receiver arranged to receive a second ultrasonic signal is also provided. The system further comprises a signal processing subsystem which comprises an analogue domain; a digital domain; a digital to analogue converter; and an analogue to digital converter. The signal processing subsystem is arranged to generate an estimated direct path signal in said digital domain, convert said estimated direct path signal to an analogue estimated direct path signal using said digital to analogue converter, subtract said analogue estimated direct path signal from said second signal to produce a modified received signal and convert said modified received signal to a digital modified received signal using said analogue to digital converter.

Described herein is an ultrasound-based virus shield. The ultrasound-based virus shield may include an ultrasound sonar emitter configured to emit a first sonar signal including a header with key data, and an ultrasound sonar receiver configured to receive a second sonar signal. The ultrasound-based virus shield may include a processor configured to: calculate a distance between the ultrasound-based virus shield and a subject in response to determining that the second sonar signal includes the key data associated with the first sonar signal, and activate an ultrasound sterilizing emitter in response to determining that the distance calculated is less than a threshold distance. An ultrasound sterilizing emitter of the ultrasound-based virus shield may be configured to emit a sterilizing signal.

A method for use in acoustic imaging, comprising: transmitting, from a transmitter, a first sound wave pulse at a first frequency determined by a maximum sampling rate of a receiver; transmitting at least one second sound wave pulse at a frequency substantially equal to the first frequency, the first and at least one second sound wave pulses being transmitted substantially within a fraction of a sample interval of the receiver; receiving and sampling, at the receiver, a reflection of at least two of the first and at least one second pulses to generate a set of receiver samples; and expanding the set of receiver samples, based on the first frequency and a total number of the first and at least one second pulses transmitted, to generate an expanded sample set with a larger number of samples than the set of receiver samples.

An ultrasonic sensor includes a case, a piezoelectric element, and two weight portions. The case includes a circumferential wall portion extending in an axial direction. The two weight portions are provided on the circumferential wall portion outside the case so as not to overlap each other as seen in the axial direction. When a bottom portion of the ultrasonic sensor bends toward one side in the axial direction during vibration at a frequency of a first vibration mode, the two weight portions incline toward the other side in the axial direction. When the bottom portion bends toward one side in the axial direction during vibration at a frequency of a second vibration mode, the two weight portions incline toward one side in the axial direction.

An object of the invention is to provide an ultrasonic CT device in which a reflected signal or the like from an object disposed close to transducers is received, and a reception signal thereof can be received by a receiver while transceivers whose number is smaller than the number of the transducers are used. The ultrasonic CT device includes: a transducer array in which a plurality of transducers are arranged; transceivers whose number is smaller than the number of the transducers; and a transmission transducer selector and a reception transducer selector disposed for each of the transceivers. While a transmitter included in the transceiver is selectively connected to any of the transducers in the transducer array by the transmission transducer selector, a receiver included in the transceiver is selectively connected to any of the transducers in the transducer array by the reception transducer selector.

A system for detecting objects using ultrasonic waves and methods for making and using the same are provided. The object detection system uniquely encodes each of a plurality of ultrasonic waves and transmit each of the uniquely-encoded ultrasonic waves in a respective direction. The object detection system then receives any of the emitted uniquely-encoded ultrasonic waves that are reflected from an object. By decoding the reflected ultrasonic waves, the object detection system distinguishes among the uniquely-encoded ultrasonic waves and detect the existence and location of the object.

Systems and techniques are described that provide automated parking assistance for a vehicle. In some implementations, a parking assistance apparatus includes a frequency generator configured to generate a first frequency and a second frequency, and generate at least one synthesized frequency that is synthesized from the first frequency and the second frequency. The apparatus also includes a piezoelectric converter configured to, using piezoelectric effects, transmit ultrasonic waves having the at least one synthesized frequency, and receive reflected ultrasonic waves that result from the transmitted ultrasonic waves being reflected by an object. The apparatus also includes a filter unit configured to detect a predetermined frequency from the reflected ultrasonic waves.

Ultrasonic ranging systems and methods that emit coded bursts and correlate transduced acoustical echoes of the bursts with a receive template characterizing a burst code to determine time-of-flight information use receive templates of time-variable length to improve short-range object detection. The template length is based on a time index measured from the start of the burst emission. The detection can account for a dead zone of transducer ringing following a burst. A time-variable gain that is also based on the time index can be applied to the correlated signal. The length and gain can be adjusted with reduced temporal frequency to reduce computation cost.