Techniques are disclosed for systems and methods to provide accurate and reliable compact sonar systems for mobile structures. A sonar system includes multiple sensor channels, each comprising a sonar transmitter and a sonar receiver, and a logic device configured to provide control signals and receive sensor signals from the sensor channels. The logic device is configured to provide transmission signals to sonar transducer assemblies, where signal patterns of the transmission signals are differentiated based at least in part on frequency content. Acoustic returns are processed using the signal patterns to reduce inter-channel pickup between the sensor channels. Resulting sonar data and/or imagery may be displayed to a user and/or used to adjust a steering actuator, a propulsion system thrust, and/or other operational systems of the mobile structure.

An ultrasonic cleaning apparatus comprising: a tank for in use receiving a cleaning liquid and an item to be cleaned; a plurality of transducers arranged, when driven, to direct ultrasonic pressure waves into the tank; and a controller arranged in use to drive the transducers. First and second transducers from the plurality of transducers are arranged in use to direct ultrasonic pressure waves into an overlapping volume; and the controller is arranged in use to drive the first and second transducers to produce ultrasonic pressure waves at different frequencies from each other. The controller is arranged to in use produce first and second drive signals for the transducers using first and second frequency generators to each switch between primary and secondary operation, with the sequential switching taking place to cause different combinations of primary and secondary operation for the first and second frequency generators to occur over time.

An ultrasonic vibrator driving apparatus performs driving by applying an alternating voltage as a drive voltage to an ultrasonic vibrator that includes a piezoelectric element and has a unique resonance frequency. The drive voltage is generated with a variable frequency in a frequency range including the resonance frequency of the ultrasonic vibrator. The frequency of the drive voltage is repeatedly swept with a predetermined sweep width and a predetermined sweep period so as to include the resonance frequency, based on a reference frequency set according to the resonance frequency of the ultrasonic vibrator. The sweep period and the sweep width are restricted by being associated so as to fall within a predetermined allowed range on a two-dimensional map divided by the sweep period and the sweep width.

Various embodiments are directed to a method of driving an end effector coupled to an ultrasonic drive system of a surgical instrument. The method comprises generating at least one electrical signal. The at least one electrical signal is monitored against a first set of logic conditions. A first response is triggered when the first set of logic conditions is met. A parameter is determined from the at least one electrical signal.

A system includes a needle, an actuator assembly and a generator. The needle is configured to be vibrated so as to emulsify a lens of an eye. The actuator assembly, includes a first actuator, a second actuator and a third actuator, which are distributed around a longitudinal axis of the needle and are configured to vibrate along the longitudinal axis in response to a first driving signal, a second driving signal and a third driving signal, respectively. The generator is configured to generate the first driving signal, the second driving signal and the third driving signal, so as to vibrate the needle in accordance with a predefined pattern.

A method for exciting sound-wave producing transducers (7) which have operating frequencies defining a transducer frequency range, in which a generator (9) produces an electrical excitation signal for the transducers (7), these electrical excitation signal being fed to the transducers (7), wherein the generator (9) carries out frequency sweeps in a frequency sweep range between a minimum frequency (f.sub.min) and a maximum frequency (f.sub.max) with an adjustable sweep rate, with a target frequency (f.sub.Ziel) being defined within said frequency sweep range, this method being characterized in that the minimum frequency (f.sub.min), the maximum frequency (f.sub.max) and the target frequency (f.sub.Ziel) are selected in such a way that a first frequency difference (f.sub.1) between the minimum frequency (fmin) and the target frequency (f.sub.Ziel) differs in terms of magnitude from a second frequency difference (f.sub.2) between the maximum frequency (f.sub.max) and the target frequency (f.sub.Ziel) within a number of frequency sweeps, and wherein the minimum frequency (f.sub.min) and/or the maximum frequency (f.sub.max) and/or the target frequency (f.sub.Ziel) is/are modified after at least one frequency sweep in such a way that an arithmetic mean of the first frequency differences (f.sub.1), formed over all frequency sweeps carried out, and an arithmetic mean of the second frequency differences (f.sub.2), formed over all frequency sweeps carried out, are substantially the same in terms of magnitude.

A vibration device includes a vibration body including a light-transmitting portion including first and second main surfaces opposing each other and a vibration portion that is continuous with the light-transmitting portion and vibrates with a main vibration together with the light-transmitting portion, and a piezoelectric vibrator fixed to the vibration portion. Localized vibration portions which generate a localized vibration different from the main vibration are provided at a position not overlapping with a center or approximate center of the light-transmitting portion.

A piezoelectric driving device includes a piezoelectric vibrating body and a driving circuit. The piezoelectric vibrating body includes a contact which comes into contact with a driven member, and a piezoelectric element which generates vibration in accordance with a driving voltage. The driving circuit sets a driving frequency of the driving voltage to a first frequency and starts the driving at the time of initiation from a stopped state, and sets the driving frequency of the driving voltage to a second frequency lower than the first frequency in a driving state after the initiation.

A transducer has an input and produces a mechanical output, wherein the magnitude of the mechanical output of the transducer is dependent on the frequency and magnitude of current at the input. A driver for the transducer includes a device having a transfer function associated with the device, the device having a device input and a device output, the device output being connectable to the input of the transducer and the device input being connectable to a power source. The device attenuates the current output at a frequency that causes a peak in the magnitude of the mechanical output of the transducer.

An excitation device includes an output circuit to output a drive signal having a frequency component to drive a piezoelectric element to vibrate an object using a vibrating body, and a control circuit including vibration modes to control the output circuit to apply to the piezoelectric element a drive signal having a frequency based on a resonant frequency of a vibrator including the object, the vibrating body, and the piezoelectric element, the modes including a predetermined vibration mode in which the frequency of the drive signal is about 1/(2n+1) times or about (2n+1) times the resonant frequency of the vibrator, and n is a positive integer.