Abstract: A system and method for measuring velocity in a fluid medium utilizing a measuring system are disclosed, wherein the measuring system comprises a transducer. In one aspect, the method comprises transmitting a first set of one or more signals of a bandwidth substantially broader than the bandwidth of the measuring system, receiving echoes from the first set of signals, obtaining a first velocity estimate based at least in part on the echoes from the first set of signals, transmitting a second set of one or more signals of a bandwidth, substantially equal to, or narrower than the bandwidth of the measuring system, receiving echoes from the second set of signals, obtaining two or more possible velocity estimates based at least in part on the echoes from the second set of signals, and selecting one of the possible velocity estimates based on the first velocity estimate.

Abstract: In an ultrasonic transducer array, a plurality of vibrators arranged in an array is bonded to a base plate by bond material. The bond material bonds the bottom of the each vibrator to the base plate in a manner to surround lower part of the side face of the vibrator. A filling material is filled in between the vibrators. The filling material has a multi-layer structure of different rigidity. In a double layer structure of the filling material, it is preferable that thickness ratio of layer of filling material at the base plate side (lower side) to the other layer of the filling material is 1:1 to 1:3. Preferably, a beam is provided for connecting the side faces of the adjacent vibrators.

Abstract: One or more embodiments of the present invention are aimed at a device for ships, in particular for multihull ships and high-speed multihull ships making it possible to avoid obstacles, in particular obstacles submerged at low depth. In at least one embodiment, the device according to the invention comprising at least: two transmitters of acoustic waves spaced apart from one another and transmitting waves of distinct frequencies or of different waveforms, an acoustic receiver, whose reception band is suitable for the emission frequencies of the transmitters, means of processing of the received signals, these means performing, through the echoes received, a measurement of the difference of the propagation times and a measurement of the differential Doppler frequency of the waves transmitted by each of the transmitters; these processing means thus determining from these measurements the position of and object having returned an echo.

Abstract: Electrode layers 22A-22C, 24A-24C are formed on both main surfaces of each of piezoelectric layers 20A, 20B. Voltages of different polarities are respectively applied to the electrode layers next to each other on the same main surface and to the electrode layers opposing to each other via the piezoelectric layer. Projection forms 30, 32 are formed in respective edges of the second electrode layers 22B, 24B, each of which extends into the opposite area. Through-holes are formed in the piezoelectric layer 20A, 20B, in positions off a division line 38. The electrode layers 22A-22C are connected together by the through-holes 26A, 26B and the projection form 30, to have an equal potential. Those are lead from the diaphragm to the outside, thus reducing the overall thickness.