A method of operating electro-acoustical transducers such as PMUTs involves applying to the transducer an excitation signal over an excitation interval, acquiring at the transducer a ring-down signal indicative of the ring-down behavior of the transducer after the end of the excitation interval, and calculating, as a function of said ring-down signal, a resonance frequency of the electro-acoustical transducer. A bias voltage of the electro-acoustical transducer can be controlled as a function of the resonance frequency. An acoustical signal received can be transduced into an electrical reception signal and a damping parameter of the electro-acoustical transducer can be calculated as a function of the ring-down signal so that a cross-correlation reference signal can be synthesized as a function of the resonance frequency and the damping ratio of the electro-acoustical transducer. Such a cross-correlation reference signal can be used for cross-correlation with the electrical reception signal to improve the reception quality.

A method of operating electro-acoustical transducers such as PMUTs involves applying to the transducer an excitation signal over an excitation interval, acquiring at the transducer a ring-down signal indicative of the ring-down behavior of the transducer after the end of the excitation interval, and calculating, as a function of said ring-down signal, a resonance frequency of the electro-acoustical transducer. A bias voltage of the electro-acoustical transducer can be controlled as a function of the resonance frequency. An acoustical signal received can be transduced into an electrical reception signal and a damping parameter of the electro-acoustical transducer can be calculated as a function of the ring-down signal so that a cross-correlation reference signal can be synthesized as a function of the resonance frequency and the damping ratio of the electro-acoustical transducer. Such a cross-correlation reference signal can be used for cross-correlation with the electrical reception signal to improve the reception quality.

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.

In one example, a method performed by electronic circuitry comprises: causing a transducer to transmit a first signal; receiving a second signal from the transducer; computing distances responsive to a time between the first and second signals; determining a vibration characteristic based on the distances; reading reference vibration characteristics from data in a memory; comparing the input vibration characteristic to the reference vibration characteristics; and responsive to the comparing, performing at least one of: providing a signal representing a status of the comparing; or updating the data in the memory.

In one example, a method performed by electronic circuitry comprises: causing a transducer to transmit a first signal; receiving a second signal from the transducer; computing distances responsive to a time between the first and second signals; determining a vibration characteristic based on the distances; reading reference vibration characteristics from data in a memory; comparing the input vibration characteristic to the reference vibration characteristics; and responsive to the comparing, performing at least one of: providing a signal representing a status of the comparing; or updating the data in the memory.

A method of monitoring both liner wear and charge impact in an industrial mill uses a sensor mounted on an elongated element deployed through a shell into a liner of the mill. The elongated element wears at a same rate as the liner under conditions within the shell. Liner wear is related to a reduction in length of the elongated element as measured by travel time of an ultrasound wave, while location and strength of charge impact is related to change in amplitude of vibrations caused by the charge impact. Liner wear measurement can be improved by using shear ultrasound waves instead of conventional longitudinal ultrasound waves. A mill monitoring apparatus has a means for acquiring ultrasonic waves and audible sound waves using the same digitizer; a means for determining the angular position of the monitoring apparatus; and a means for supplying electric power to the apparatus.

In a sonar-based transducer system, single or multiple transducers may collect and transmit data to a management module for analysis to optimize and/or control a process. Secondary sensors may provide additional product data for analysis. Historical data may be stored in a data library for future reference. Real time data may be transmitted to a control center via a virtual dashboard.

A thermal excitation acoustic-wave-generating device includes a first heating element, a substrate that includes a main surface along which the first heating element is disposed, and a facing body that faces the substrate with the first heating element interposed therebetween. The substrate and the facing body define a path for an acoustic wave. A length of the path is close to a whole number multiple of ¼ of a wavelength of the acoustic wave.

An object detection system includes: a transmission unit configured to sequentially transmit a plurality of transmission waves to which identification information different from one another is applied; a reception unit configured to sequentially receive a plurality of reception waves respectively corresponding to the plurality of transmission waves returned in response to reflection by an object after all the plurality of transmission waves are transmitted by the transmission unit; and a detection processing unit configured to detect information related to the object based on a relationship between the plurality of transmission waves and the plurality of reception waves.

An object detection system includes: a transmission unit configured to sequentially transmit a plurality of transmission waves to which identification information different from one another is applied; a reception unit configured to sequentially receive a plurality of reception waves respectively corresponding to the plurality of transmission waves returned in response to reflection by an object after all the plurality of transmission waves are transmitted by the transmission unit; and a detection processing unit configured to detect information related to the object based on a relationship between the plurality of transmission waves and the plurality of reception waves.