Abstract: There is disclosed an acoustic transducer for communications within an operational bandwidth, the transducer comprising: A signal generator for generating a signal at a centre-frequency within the operational bandwidth; A piezoelectric element having a dielectric constant that varies with temperature; A driving electrode at the surface of the piezoelectric element; A matching network, having a natural frequency at a given temperature, and operable to transfer the signal from the signal generator to the piezoelectric element whilst mitigating electrical loss, the matching network being connected to the driving electrode; Wherein the matching network comprises a temperature compensating capacitor connected in parallel with the piezoelectric element, the temperature compensating capacitor being for counteracting temperature-induced changes to the dielectric constant of the piezoelectric element such that the electrical natural frequency of the transducer is substantially constant over a range of temperatures.

Abstract: An optical selector arrangement (22), comprising: a first set of optical ports (30), having a first number of optical ports, the first number being greater than or equal to 2; a second set of optical ports (42), having a second number of optical ports, the second number being greater than the first number; the second set of optical ports being for communicating with the first set of optical ports, a selector interface (40) for the optical selector arrangement, the selector interface comprising the second set of optical ports (42), a part of the optical selector arrangement functioning as a selector (44), the selector being arranged to selectively optically couple the first set of optical ports (30) to a set of ports of the second set of optical ports (42) of the selector interface, the selector (44) being rotatable relative to the selector interface (40) to facilitate the selection by optically aligning the first set of optical ports (30) to the second set of optical ports (42) of the selector interface (40);

Abstract: There is disclosed an acoustic transducer for communications within an operational bandwidth, the transducer comprising: A signal generator for generating a signal at a centre-frequency within the operational bandwidth; A piezoelectric element having a dielectric constant that varies with temperature; A driving electrode at the surface of the piezoelectric element; A matching network, having a natural frequency at a given temperature, and operable to transfer the signal from the signal generator to the piezoelectric element whilst mitigating electrical loss, the matching network being connected to the driving electrode; Wherein the matching network comprises a temperature compensating capacitor connected in parallel with the piezoelectric element, the temperature compensating capacitor being for counteracting temperature-induced changes to the dielectric constant of the piezoelectric element such that the electrical natural frequency of the transducer is substantially constant over a range of temperatures.

Abstract: An optical selector arrangement (22), comprising: a first set of optical ports (30), having a first number of optical ports, the first number being greater than or equal to 2; a second set of optical ports (42), having a second number of optical ports, the second number being greater than the first number; the second set of optical ports being for communicating with the first set of optical ports, a selector interface (40) for the optical selector arrangement, the selector interface comprising the second set of optical ports (42), a part of the optical selector arrangement functioning as a selector (44), the selector being arranged to selectively optically couple the first set of optical ports (30) to a set of ports of the second set of optical ports (42) of the selector interface, the selector (44) being rotatable relative to the selector interface (40) to facilitate the selection by optically aligning the first set of optical ports (30) to the second set of optical ports (42) of the selector interface (40);

Abstract: Signal processing apparatus located in and/or mounted on an entity (e.g. an aircraft), the signal processing apparatus comprising: a first module; a second module connected to the first module such that signals may be sent between those modules; one or more amplifiers configured to amplify signals sent between the modules; and one or more optical fibres. The first module is located at a first location in/on the entity. The second module and the one or more amplifiers are located at a second location in/on the entity. The first location and the second location are spatially separate, i.e. remote from one another. The optical fibre(s) couple together the first and the second locations such that a signal sent between those locations is sent via the optical fibre(s).

Abstract: There is disclosed an integrated lighting and network-interface device comprising a housing defining an aperture, a lens supported at the aperture for allowing light and 55-65 GHz radiation to pass therethrough, a light source, a transceiver module having an antenna unit, the transceiver module being adapted for connection to an optic fibre port, and being for operation at at least one centre frequency between 55 GHz and 65 GHz, wherein the light source and the antenna unit are disposed in the housing and arranged to radiate through the lens.