In the fields such as evacuation guidance and entertainment, it is important for each listener to provide different sound information by using some loudspeakers in a same room. However, listeners have difficulty obtaining target sound information because various sound signals are mixed by using a general loudspeaker which has a wide directivity. To solve this problem, a parametric loudspeaker w...

Ultrasonic transducers play a significant role in generating and receiving the acoustic waves in ultrasonic flowmeters. Depending on the required accuracy, the ultrasonic transducers can be installed either in one pair or more in an ultrasonic flowmeter. The main part of an ultrasonic transducer is its piezoceramic element. In this work, four piezoceramic elements with different diameter to thi...

Practical aspects of design and application radio frequency (RF) transformers in an ultrasonic system excitation channel are analysed. Design steps are discussed for those willing to design their own transformer an for excitation channel. Investigation has been carried out on what generator parameters can be obtained if instead of a purely active output stage the impedance matching RF transform...

The technique in artificial ultrasonic transducer using electronics is very bulky and power hungry. We switched over to ultrasonic Micro-Electronics Mechanical Systems (MEMS) which have shown significant importance for miniaturized mechanical system, based on silicon technology. MEMS based acoustic sensing transducers commonly employ the piezo-electric technology to interpret the received ultra...

Ultrasonic ranging is the most common method used in robotic systems for distance or proximity sensing. The heart of the method is an ultrasonic transducer that emits and detects ultrasound. There are mainly two types of transducers existing in the market today; piezoelectric and electrostatic. In this paper, we propose the use of a new type of transducer, which is capacitive micromachined ultr...

We report on the development of transducers for ultrasonic flaw detection which can be permanently mounted at critical locations on structures. We will show that MEMS capacitive diaphragm transducers can be bonded to metal or plexiglas test speciments without damage and that ultrasonic energy can be efficiently coupled into the transducer. It will be demonstrated that transducer arrays can be o...

Compared with single-focus optical-resolution photoacoustic microscopy (OR-PAM), multifocal OR-PAM utilizes both multifocal optical illumination and an ultrasonic array transducer, significantly increasing the imaging speed. A reflection-mode multifocal OR-PAM system based on a microlens array that provides multiple foci as well as an ultrasonic array transducer that receives the excited photoa...

A unique sensing system is described using an ultrasonic transducer for measuring tree trunk diameters in the orchard. Trunk diameters were calculated from the time it took sound waves to travel from the transducer to the trunk and back to the sensor. The device was calibrated with objects ranging in diameter from 1.6 (0.63 inch) to 19.0 cm (7.5 inches). The distance between the transducer and ...

Scanning thermoacoustic tomography was explored in the microwave region of the electromagnetic spectrum. Short microwave pulses were used to induce acoustic waves by thermoelastic expansion in biological tissues. Cross sections of tissue samples were imaged by a linear scan of the samples while a focused ultrasonic transducer detected the time-resolved thermoacoustic signals. Based on the micro...