Abstract: The present invention relates to a system for writing an optical structure in a waveguide. The system including, means for splitting a light beam into two coherent writing beams, an optical circuit for directing the writing beams along substantially the same optical path in opposite directions such that they produce an interference pattern in an interference region substantially within the waveguide to write the optical structure, said optical circuit including at least two acousto-optic modulators (AOMs) configured to enable a controllable phase shift to be applied to a light beam propagating therethrough, the two AOMs being arranged such that, in use, each AOM shifts the phase of only one of the writing beams, to thereby provide a controllable phase difference between the writing beams.

Abstract: An electronic metal detector having, a transmit coil arranged and adapted to transmit an alternating magnetic field associated with a reactive transmit coil voltage, the transmit coil being connected to transmit electronics arranged and adapted to generate a transmit signal, the transmit electronics having at least two power sources, a first power source and a second power source, wherein the first power source is adapted and arranged to connect to the transmit coil for at least a first period, and the second power source is adapted and arranged to connect to tie transmit coil for at least a second period, the said transmit electronics including at least one servo control negative feedback loop, a first servo control negative feedback loop, which is adapted and arranged to monitor a transmit coil current for at least part of the said first period, and to control at least part of the said transmit signal, the transmit electronics being adapted and arranged to control the transmit signal to produce the reactive

Abstract: A blind slat (1) has a substantially constant cross-sectional profile extending between a leading end (2) and a trailing end (3). The profile defines an upper face (4) of the slat (1). The upper face (4) has a convex portion (6) extending from adjacent the leading end (2) towards the trailing end (3). The convex portion (6) has an apex (7) at which the upper face (4) is parallel to a reference axis (R) of the profile that extends laterally between the leading end (2) and the trailing end (3). The upper face (4) also has a concave portion (8) located between the convex portion (6) and the trailing end (3). The concave portion (8) has a base (9) at which the upper face (4) is parallel to the reference axis (R). An inflection (10) joins the convex portion (6) and the concave portion (8). The upper face (4) is inclined with respect to the reference axis (R) by at least 11° at the inflection (10). The profile has a depth measured between the leading end (2) and the trailing end (3) of between 105 and 150 mm.

Abstract: This disclosure relates to a method of configuring an engine control system for controlling the engine of a vehicle. The method involves displaying one or more graphical representations of functional elements to be performed by the engine control system and then modifying the one or more functional elements by making changes to the displayed graphical representations. This allows the engine control system to be readily reconfigured by a user. This disclosure also relates to an apparatus for configuring an engine control system and a new engine control system. A computer program product including a computer readable medium having a computer program recorded on it for configuring an engine control system is also disclosed.

Abstract: A security light is provided comprising a mounting base for attachment to a support therefor; sensor means on the mounting base for detecting the presence of a person or moving object within a radial range of the sensor means and within any one of a plurality of angularly adjacent sectors radiating from the mounting base that together cover an angular field of operation of the security light. A light source and reflector assembly has an angular field of illumination at least equal to the angular field of each of the angularly adjacent sectors and is angularly movable relative to the mounting base between a plurality of positions corresponding to the plurality of angularly adjacent sectors so as to be selectively directed in a direction in which the field of illumination covers an entire sector.

Abstract: Measuring ethanol vapour concentration comprising; introducing an ethanol vapour sample into a fuel cell that is adapted to generate an output which is proportional to the ethanol vapour concentration of the ethanol sample; a voltage measurement circuit; a current measurement circuit; and means to switch the fuel cell output either to the voltage measurement circuit or to the current measurement circuit in dependence on one or more predetermined signal measurement parameters. The signal measurement parameter may be the temperature of the fuel cell.

Abstract: Provided herein is a loudspeaker system utilizing one or more ducted slot ports. In various embodiments, a ducted slot port may incorporate an acoustic low pass filter, such as a bend in the airflow path, to control midrange leakage. A ducted slot port may also minimize standing waves within the port duct and control turbulent port noise, such as by varying its cross-sectional area substantially continuously and symmetrically along the port duct's entrance-exit axis.

Abstract: A method for generating a transmit signal for transmission including the steps of a) generating at least two selected rectangular wave signals, each having a different fundamental frequency; b) mixing the selected rectangular wave signals to produce a driving signal; and c) driving a switching circuit using the driving signal for generating a transmit signal for transmission, wherein the Fourier transform of the transmit signal contains frequency components of relatively high magnitude, at frequencies corresponding to the convolution of the fundamental frequencies of the said at least two selected rectangular wave signals, as compared to other frequency components across the frequency spectrum of the Fourier transform, and wherein the rectangular wave signals are selected such that the frequency components of relatively high magnitude are substantially the same in magnitude, and spaced from each other in the frequency spectrum in a predetermined manner.

Abstract: A method for detecting a target in a soil, including the step of generating a transmit signal, the transmit signal including at least three different frequency components, a relatively high frequency component, a relatively medium frequency component and a relatively low frequency component; and processing a receive signal, the processing including selecting coefficients for, in effect, linearly combining the relatively high frequency components, the relatively low frequency components and the relatively medium frequency components of the receive signal to produce an indicator output signal, the indicator output signal including a signal indicative of the presence of the target in the soil, and wherein the coefficients are selected such that the indicator output signal is approximately independent of log-linear frequency-dependent resistive signal components and log-uniform resistive signal components from the soil.

Abstract: A highly flexible real-time metal detector platform which has a detection capability for different targets and applications, where the operator is able to alter synchronous demodulation multiplication functions to select different types or mixtures of different types to be applied to different synchronous demodulators, and also different waveforms of the said synchronous demodulation multiplication functions; examples of the different types being time-domain, square-wave, sine-wave or receive signal weighted synchronous demodulation multiplication functions. The operator can alter the fundamental frequency of the repeating switched rectangular-wave voltage sequence, and an operator may alter the waveform of the repeating switched rectangular-wave voltage sequence and corresponding synchronous demodulation multiplication functions.

Abstract: An electronic metal detector having, a transmit coil arranged and adapted to transmit an alternating magnetic field associated with a reactive transmit coil voltage, the transmit coil being connected to transmit electronics arranged and adapted to generate a transmit signal, the transmit electronics having at least two power sources, a first power source and a second power source, wherein the first power source is adapted and arranged to connect to the transmit coil for at least a first period, and the second power source is adapted and arranged to connect to tie transmit coil for at least a second period, the said transmit electronics including at least one servo control negative feedback loop, a first servo control negative feedback loop, which is adapted and arranged to monitor a transmit coil current for at least part of the said first period, and to control at least part of the said transmit signal, the transmit electronics being adapted and arranged to control the transmit signal to produce the reactive

Abstract: A distributed stereo system includes two (or more) speakers; a source of audio signals; an amplifier in the same room as the speakers that drives the speakers; and a mains-operated electrical power supply to power the amplifier. The amplifier is remote from the signal source and power supply and is connected to the signal source and power supply by means of a category 5, four-pair twisted cable or similar, which provides right and left channel audio signals from the signal source to the amplifier and DC power from the power supply to the amplifier. A distributed intercom system features a bi-directional intercom hub; a mains-operated power supply; and two or more remote modules each having an amplifier and speaker. The modules are connected to the hub via category 5 cable or similar, which carries audio signals between the hub and the modules and power from the supply to the modules.

Abstract: This invention concerns a distributed stereo audio system. Distributed stereo audio systems are used to provide stereo sound to several rooms or areas from a single source of signal. The system includes two or more speakers for the broadcast of stereo audio signals; a source of stereo audio signals; a stereo amplifier to amplify stereo audio signals and drive the speakers; and a mains operated electrical power supply to provide power to the amplifier. The amplifier is located in the same room as the speakers, and remote from the signal source and power supply. The amplifier is connected to the signal source and power supply by means of a category 5 four pair twisted cable which provides, in respective twisted pairs, right channel audio signals from the signal source to the amplifier, left channel audio from the signal source to the amplifier, DC power from the power supply to the amplifier, and control signals from the amplifier to the signal source.