Bae Systems, Inc.

Gec-Marconi Limited

Duncan Peter Rowe

Lionel William John Kent

John Martin Bagshaw

Nicholas John Archer

Matthew Robert Gore

Stephen Derek Finch

Communication apparatus comprises a first transceiver unit (A) and a signal processing device () configured to receive a signal from the first transceiver unit and to produce a signal for transmission by the first transceiver unit. A cable (A) connects the first transceiver unit to the signal processing device. The first transceiver unit comprises a housing; a first pair of transducers (T,R) located at, or adjacent, a first end of the housing, and a second set of transducers (T,R) located at, or adjacent, an opposite end of the housing.

Communication apparatus

In an arrangement for transmitting power or data through a solid rigid substrate without penetrating the substrate, acoustic transducer components are mounted on the substrate by means of strain isolator elements which are welded or otherwise bonded to the substrate and providing an attachment surface to which the attachment interface of the acoustic transducer may be attached. The strain isolator element is of the same or similar acoustic impedance as the rigid substrate and may indeed be formed of the same material. Various geometries of strain isolator are disclosed, including a plain spacer block, and one comprising a stalk attached to the solid rigid substrate and topped by a disc in a 'mushroom' configuration.

Mounting arrangements

In an arrangement for transmitting power or data through a solid rigid substrate without penetrating the substrate, acoustic transducer components are mounted on the substrate by means of strain isolator elements which are welded or otherwise bonded to the substrate and providing an attachment surface to which the attachment interface of the acoustic transducer may be attached. The strain isolator element is of the same or similar acoustic impedance as the rigid substrate and may indeed be formed of the same material. Various geometries of strain isolator are disclosed, including one comprising a stalk attached to the solid rigid substrate and topped by a disc in a 'mushroom' configuration.

There is disclosed a transducer apparatus for acoustic communications through a substrate at a predetermined center frequency, the apparatus comprising:&#x2014;an active piezoelectric element for generating an acoustic signal; an intermediate layer, having a surface for accommodating the piezoelectric element, and having a first array of protrusions on a surface opposite the surface for accommodating the piezoelectric element; and a second array of protrusions at the substrate, wherein the active piezoelectric element is mounted onto the intermediate layer, and the intermediate layer is secured in position relative to the substrate such that the first array of protrusions faces the second array of protrusions such that the acoustic signal may propagate through the first and second arrays. There are further disclosed a method of mounting such an apparatus and a plate suitable for use in the transducer apparatus.

Transducer arrangement

The relative position (M) of two members (33, 34) is sensed by scanning (S) an optical beam (25) over an encoded pattern (20) carried by one of the members, and by using a read head (21) secured to the other member to receive an optical signal transmitted from the encoded pattern (20). This optical signal is received by an optical position sensor to discriminate from the frequency of the signal, the position of the read head (21) relative to the encoded pattern (20). As the relative position is detected from the frequency of the signal rather than its intensity, components can be replaced without recalibration. The optical beam (25) is scanned by using a light source of variable wavelength which is passed through a device, such as a diffraction grating or a gradient index lens, for deflecting the beam (25) dependent on its wavelength.

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Chelmsford, United Kingdom

Duncan Peter Rowe