Abstract: A method is provided to measure a modulus of complex sensitivity of hydrophone data channels using a quasi-diffuse sound field. In the method, a radiation pattern representing shallow water sources directs to a location as a direct acoustic path and sound reflects to the location from the water bottom as a reflected acoustic path. At least one hydrophone receives the sounds at the location as acoustic signals with an acoustic intensity being the sound intensities along the acoustic paths. The sound intensity at the hydrophones also relates to a zenith angle and a bottom intensity reflection coefficient. The modulus of the frequency dependent sensitivity of the hydrophone is computed from measurements of the voltage output and voltages of reference hydrophones with the sound intensity as factor and with uncertainty reduced by averaging hydrophone sensitivities.

Abstract: An ultrasonic sensor includes an ultrasonic element and an element accommodation case. A side wall portion of the element accommodation case has a tubular shape surrounding a directional central axis. A bottom wall portion and a top wall portion of the element accommodation case cover ends of the side wall portion in a direction along the directional central axis. The top wall portion has a diaphragm portion. The bottom wall portion supports the ultrasonic element. For example, the ultrasonic element is opposed to the diaphragm portion across a gap defining an interval corresponding to an integral multiple of half of a wavelength of ultrasonic vibration. Alternatively, the diaphragm portion is formed of a material having an acoustic impedance of 50×105 Pa·s/m or more and 5000×105 Pa·s/m or less, and has a thickness of 1 mm or less.

Abstract: 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.

Abstract: According to various embodiments, a system for acoustic to electronic transduction is disclosed. The system includes a transducing medium configured to convert a received acoustic signal into a transduced electronic signal when a voltage is applied. The system further includes a high-pass filter coupled to the transducing medium, the high-pass filter configured to isolate the transduced signal from the applied voltage.

Abstract: Example sonar transducer assemblies configured for reduced interference are provided herein. An example sonar transducer assembly includes a housing, a first transducer, and a second transducer. The first transducer is positioned within the housing such that a length is configured to extend in a first mounting plane and a produced first beam defining a fan-shape extends in a first plane. The second transducer is positioned at a tilted angle within the housing such that a length is configured to extend in a second mounting plane and a produced second beam defining a fan-shape is in a second plane. The second mounting plane is non-parallel to the first mounting plane and is offset from the first mounting plane by at least 1 degree such that the second plane is not parallel to the first plane so as to reduce interference between the first transducer and the second transducer.

Abstract: Disclosed is a method of forming a transmission beam with a transducer array comprising a plurality of transducers, the method comprising: receiving at least one desired property for an intended transmission beam; determining an optimised operation parameter for a transducer of the transducer array based on the received at least one desired property and an array model for modelling a relationship between at least one beam property and at least one transducer protection property whilst taking into account of an acoustic mutual coupling of the plurality of transducers of the transducer array; and generating the transmission beam using the optimised operation parameter on the transducer array.