Abstract:
An apparatus and method associated with amplifying piezoelectric sonic and ultrasonic outputs is presented which provides high power output from piezoelectric devices, especially at high ultrasonic frequencies, in open air, which mitigates or eliminates overheating of the piezoelectric devices when stimulated at or near their peak outputs for extended periods. In addition, the invention provides a means of amplifying a piezoelectric sonic and ultrasonic device if a desired output power exceeds a normal maximum capability of the piezoelectric device.
Abstract:
An ultrasonic image scanning system for scanning an organic object includes a container for containing a coupling medium for transmitting an ultrasonic signal to the organic object disposed therein whereby a simultaneous multiple direction scanning process may be carried out without physically contacting the organic object. The ultrasonic image scanning system further includes ultrasound transducers for transmitting the ultrasonic signal to the organic object through the coupling medium without asserting an image deforming pressure to the organic object. These transducers distributed substantially around a two-dimensional perimeter of the container and substantially at symmetrical angular positions at approximately equal divisions of 360 degrees over a two-dimensional perimeter of the container. The transducers are further movable over a vertical direction alone sidewalls of the container for a real time three dimensional (3D) image data acquisition. The container further includes sidewalls covered with a baffle layer for reducing an acoustic reverberation.
Abstract:
The invention provides a multi-frequency transducer capable of obtaining desired directivity regardless of frequencies. Parallelepiped-shaped transducer elements (1) are used as transducer elements and a plurality of such transducer elements (1) are arranged in an array. The transducer elements (1) are caused to resonate using a resonant frequency in fundamental vibration mode and a resonant frequency in harmonic vibration mode determined by the dimensions (A, B) of a short edge (1a) and a long edge (1b) perpendicular to a longitudinal edge (1c) of each transducer element (1) to transmit and receive at multiple frequencies. The angle of directivity (θ) of the transducer elements is controlled by the dimension (C) of the longitudinal edge which is set to a value which does not affect resonance in either the fundamental vibration mode or the harmonic vibration mode.
Abstract:
An acoustic transducer design having a slotted oval-shaped shell and active transducer elements located on the inner surface of the shell is disclosed. The design provides a high power, ultra-low frequency oval projector having a number of applications, including underwater seismic prospecting and fish mitigation.
Abstract:
A substrate (2) has a surface on which is provided a modifying layer which is incomplete and has a distribution such as to provide a plurality of islands of said material and/or islands of substrate surface whereby the surface exhibits a modified electrical and/or magnetic property. As shown, substrate (2) is piezoelectric, and has a central electrode (9) and a peripheral electrode (10), between which are deposited a large number of electrically conductive dots having a dot density which decreases with distance from electrode (9). The construction acts as a sonar transducer over a relatively wide frequency range.
Abstract:
A sonar system using closely spaced or interleaved projector and receiving transducer elements with a power inductor connected in series with the projector array transmits three separate frequencies and utilizes a resonant circuit connected across the projector array, and a switch alternately connecting the array to the transmitter or the resonant circuit. The resonant circuit has two parallel branches with an inductor in one branch and an inductor, a capacitor and a resistor in the parallel branch. An alternate embodiment includes a variable capacitor in series with the parallel circuit to simplify the tuning for individual installations. Values of the components were chosen to provide impedances looking into the resonant circuit which tend to maximize the "stiffness" of the projector elements for all the received frequencies, thus inhibiting the tendency of the projector elements to receive and reradiate echo signals during the receiving cycle of the sonar system.
Abstract:
1. In combination in electronic apparatus for simulating the self-noise of submarine, means for generating a wide-band noise signal, means for modulating the noise signal at a frequency corresponding to the propeller speed of a submarine, means for generating a signal at the frequency of the tooth impacts of the main drive gear of a submarine, and amplifying and output means for both said tones.