An illustrative controller includes: a transmitter to drive an acoustic transducer to generate a first acoustic burst and a second acoustic burst; a receiver coupled to the acoustic transducer to sense a first response to the first acoustic burst and a second response to the second acoustic burst; and a processing circuit to derive output data from the first and second responses in part by determining an offset frequency difference between the first and second responses, wherein the first acoustic burst has a first characteristic frequency and the second acoustic burst has a second characteristic frequency different from the first characteristic frequency.

An illustrative controller includes: a transmitter to drive an acoustic transducer to generate a first acoustic burst and a second acoustic burst; a receiver coupled to the acoustic transducer to sense a first response to the first acoustic burst and a second response to the second acoustic burst; and a processing circuit to derive output data from the first and second responses in part by determining an offset frequency difference between the first and second responses, wherein the first acoustic burst has a first characteristic frequency and the second acoustic burst has a second characteristic frequency different from the first characteristic frequency.

An occupancy sensor device for monitoring a space includes a transmitter portion and a receiver portion. The receiver portion is located remotely from the transmitter portion. To enable reliable detection of occupancy within the monitored space, an estimate of the signal transmitted by the active sensor in the transmitter portion is compared to the signal received by the transmitted portion.

An occupancy sensor device for monitoring a space includes a transmitter portion and a receiver portion. The receiver portion is located remotely from the transmitter portion. To enable reliable detection of occupancy within the monitored space, an estimate of the signal transmitted by the active sensor in the transmitter portion is compared to the signal received by the transmitted portion.

A frequency steered sonar element comprises a transducer element and a grating element. The transducer element presents a longitudinal axis and is configured to receive a transmit electronic signal and generate an acoustic wave with a frequency component corresponding to a frequency component of the transmit electronic signal. The grating element presents a longitudinal axis and is oriented such that a longitudinal axis of the grating element and a longitudinal axis of the transducer element form an acute angle. The grating element includes a first surface and an opposing second surface. One or more of the surfaces includes one or more grooves distributed thereon, the one or more grooves including first and second facets. The grating element is configured to emit a sonar beam in an angular direction which varies according to the frequency component of the acoustic wave.

A method of optimizing acoustic transducer performance, and corresponding system, can include mechanically coupling a transducer to a fluid barrier, calibrating the acoustic transducer by measuring response as a function of drive frequency to determine one or more optimum drive frequencies, optimized for the transducer actually coupled to the fluid barrier, and storing the one or more optimum drive frequencies for use in operating the acoustic transducer. Shims may also be used between the transducer and fluid barrier, such as a boat hull, to optimize transducer performance. Embodiments can enable improved in-hull transducer depth sounding, as well as improved fluid level measurements in tanks.

A method of optimizing acoustic transducer performance, and corresponding system, can include mechanically coupling a transducer to a fluid barrier, calibrating the acoustic transducer by measuring response as a function of drive frequency to determine one or more optimum drive frequencies, optimized for the transducer actually coupled to the fluid barrier, and storing the one or more optimum drive frequencies for use in operating the acoustic transducer. Shims may also be used between the transducer and fluid barrier, such as a boat hull, to optimize transducer performance. Embodiments can enable improved in-hull transducer depth sounding, as well as improved fluid level measurements in tanks.

A method of detecting objects includes transmitting toward an object a first acoustic signal including a first set of pulses including a first number of pulses, and checking if a first echo signal resulting from reflection of the first acoustic signal is received with an intensity reaching an echo detection threshold. If the intensity of the first echo signal reaches the echo detection threshold, the distance to the object is calculated as a function of the time delay of the first echo signal. If the intensity of the first echo signal fails to reach the echo detection threshold, one or more further acoustic signals are transmitted including a set of pulses wherein the number of pulses is increased with respect to the number of pulses in said first acoustic signal.

An obstacle monitoring system includes a transducer that receives an ultrasonic echo from an obstacle and generates a signal based on the echo. The system further includes a controller coupled to the transducer that is calibrated based on a frequency response of the transducer and a coupling circuit. The system further includes circuitry generating a damping current, controlled by the controller, that reduces or eliminates reverberation of the transducer.

An apparatus for imaging structural features below the surface of an object, the apparatus comprising: a transmitter unit configured to transmit a sound pulse at the object; a receiver unit configured to receive reflections of sound pulses transmitted by the transmitter unit from the object; a signal processing unit configured to: analyse one or more signals received by the receiver unit from the object; recognise, in the one or more signals, a reflection that was caused by a first structural feature and a reflection that was caused by a second structural feature that is located, in the object, at least partly behind the first structural feature; and associate each recognised reflection with a relative depth in the object at which the reflection occurred; and an image generation unit configured to generate an image that includes a representation of the first and second structural features in dependence on the recognised reflections and their relative depths.