Abstract: A visible light positioning receiver arrangement for obtaining spatial position information of the receiver arrangement from a plurality of luminaires (5), at least one of the luminaires including at least one associated modulated light source for transmitting a light signal providing positional information of one or more reference points associated with the luminaire, said receiver arrangement including: an imaging receiver for capturing an image of the luminaires and associated said reference point(s); and a non-imaging receiver (7) for estimating an angle of arrival (AOA) of light from each said modulated light source, and for decoding the reference point positional information therefrom; wherein said AOA information and reference point positional information from the non-imaging receiver is matched to the image captured by the imaging receiver to obtain said spatial position information.

Abstract: A visible light positioning receiver arrangement for obtaining spatial position information of the receiver arrangement from a plurality of luminaires (5), at least one of the luminaires including at least one associated modulated light source for transmitting a light signal providing positional information of one or more reference points associated with the luminaire, said receiver arrangement including: an imaging receiver for capturing an image of the luminaires and associated said reference point(s); and a non-imaging receiver (7) for estimating an angle of arrival (AOA) of light from each said modulated light source, and for decoding the reference point positional information therefrom; wherein said AOA information and reference point positional information from the non-imaging receiver is matched to the image captured by the imaging receiver to obtain said spatial position information.

Abstract: An optical receiver (100) for detection of light from one or more sources (108) comprises an opaque layer (102) disposed on a first surface. An aperture (104) is formed in the opaque layer. An optical detector (106) has a detection region disposed on a second surface. The first and second surfaces are spaced apart from one another such that light passing through the aperture (104) illuminates a corresponding illumination region (110) on the second surface, and is detected by the optical detector (106) In the event that the detection region overlaps the illumination region. Multiple apertures may be formed in the opaque layer, and/or multiple optical detectors may be disposed on the second surface. The optical receiver may thereby enable optical signals originating at different locations to be detected, and distinguished, over a wide field of view.

Abstract: An optical receiver (100) for detection of light from one or more sources (108) comprises an opaque layer (102) disposed on a first surface. An aperture (104) is formed in the opaque layer. An optical detector (106) has a detection region disposed on a second surface. The first and second surfaces are spaced apart from one another such that light passing through the aperture (104) illuminates a corresponding illumination region (110) on the second surface, and is detected by the optical detector (106) In the event that the detection region overlaps the illumination region. Multiple apertures may be formed in the opaque layer, and/or multiple optical detectors may be disposed on the second surface. The optical receiver may thereby enable optical signals originating at different locations to be detected, and distinguished, over a wide field of view.

Abstract: A receiver for recovering transmitted information carried by a received optical signal that has been affected by dispersion includes an optical splitter having an input port arranged to receive the received optical signal, and a plurality of output ports. A proportion of optical power at the input port is transmitted to each of the output ports. A plurality of optical detectors is operably connected to respective output ports of the optical splitter, for generating a corresponding plurality of electrical signals. Optical phase shifters are disposed between the output ports of the optical splitter and respective optical detectors. As a result, each optical phase shifter applies a frequency dependent phase shift to an optical signal passing therethrough.

Abstract: A system (100) for transmitting digital information includes a transmitting apparatus (102) for generating an optical signal bearing digital information, a dispersive optical channel (104), and a receiving apparatus (110) for receiving the optical signal. The dispersive optical channel (104) is disposed to convey the optical signal from the transmitting apparatus (102) to the receiving apparatus (110). The transmitting apparatus includes an encoder (114) for encoding digital information into a series of blocks, each including a plurality of data symbols corresponding with one or more bits of digital information. A signal generator (118) generates a time-varying signal corresponding with each of said blocks.

Abstract: An apparatus and method are provided for receiving an optical signal having an optical carrier component and at least one information-bearing optical sideband. In general, an optical filter arrangement (110) is used to separate the optical carrier component from the information-bearing optical sideband. First and second optical splitters (126, 128) divide the optical power in the optical carrier and the optical sideband, respectively, into corresponding sub-components. The sub-components of the optical carrier have substantially orthogonal polarisation states, which is an optional characteristic of the sideband sub-components. First and second optical coupling devices (142, 144) respectively each combine one of the optical carrier sub-components with a corresponding one of the optical sideband sub-components. Optical detectors (158, 160) detect the outputs of the combiners (142, 144).

Abstract: A method of communicating digital information over a dispersive optical channel includes encoding the digital information into a plurality of data blocks, each of which includes a number of bits of the information. A time-varying electrical signal is generated which corresponds with each of said data blocks. The time-varying electrical signal is applied to an optical transmitter (122) to generate an optical signal which includes an asymmetrically amplitude limited transmitted signal modulated onto an optical carrier. The optical signal is then transmitted over the dispersive optical channel (106). At a receiving apparatus (104) the optical signal is detected to produce an electrical signal which corresponds with the asymmetrically amplitude limited transmitted signal.

Abstract: An apparatus and method are provided for receiving an optical signal having an optical carrier component and at least one information-bearing optical sideband. In general, an optical filter arrangement (110) is used to separate the optical carrier component from the information-bearing optical sideband. First and second optical splitters (126, 128) divide the optical power in the optical carrier and the optical sideband, respectively, into corresponding sub-components. The sub-components of the optical carrier have substantially orthogonal polarisation states, which is an optional characteristic of the sideband sub-components. First and second optical coupling devices (142, 144) respectively each combine one of the optical carrier sub-components with a corresponding one of the optical sideband sub-components. Optical detectors (158, 160) detect the outputs of the combiners (142, 144).

Abstract: The invention provides a new approach which is better suited to FFT design as applied to multicarrier modulation systems such as OFDM. The signals are scaled so that overflow, rather than being completely avoided, occurs with low probability throughout the IFFT and FFT structures. The size of the error that results from an overflow depends on how overflow is handled in the DSP. To minimize the degradation, overflow should result in saturation of the value at the maximum positive or negative value option. This is equivalent to clipping the signal. Using the new technique, signals within the FFT structure are scaled to balance the effect of clipping and round-off. Clipping may result in comparatively large errors in a few signal values but because of the spreading effect of the FFT and because OFDM systems typically include error coding/correction, system performance depends on the total error or, in other words the total noise power, across all of the FFT outputs rather than on any individual value.

Abstract: Methods and apparatus (100) for composing, generating and transmitting information-bearing optical signals are provided. An information-bearing electrical signal is composed (108) having desirable spectral properties, preferably configured to ensure that undesired interference between electrical spectral components generated in a square-law direct detection process (120) at a corresponding optical receiver (104) is substantially avoided. Predistortion (110) is advantageously applied to transmitted signals, in order to account for a nonlinear relationship arising in a modulation process (114) between electrical signal amplitude and corresponding optical field amplitude. Orthogonal frequency division multiplexing (OFDM) techniques may be applied to composed signals having the desired characteristics, and additionally may facilitate the application of frequency domain equalisation (128) in order to mitigate transmission impairments, including dispersion.

Abstract: A receiver for recovering transmitted information carried by a received optical signal that has been affected by dispersion includes an optical splitter having an input port arranged to receive the received optical signal, and a plurality of output ports. A proportion of optical power at the input port is transmitted to each of the output ports. A plurality of optical detectors is operably connected to respective output ports of the optical splitter, for generating a corresponding plurality of electrical signals. Optical phase shifters are disposed between the output ports of the optical splitter and respective optical detectors. As a result, each optical phase shifter applies a frequency dependent phase shift to an optical signal passing therethrough.

Abstract: Methods and apparatus (100) for composing, generating and transmitting information-bearing optical signals are provided. An information-bearing electrical signal is composed (108) having desirable spectral properties, preferably configured to ensure that undesired interference between electrical spectral components generated in a square-law direct detection process (120) at a corresponding optical receiver (104) is substantially avoided. Predistortion (110) is advantageously applied to transmitted signals, in order to account for a nonlinear relationship arising in a modulation process (114) between electrical signal amplitude and corresponding optical field amplitude. Orthogonal frequency division multiplexing (OFDM) techniques may be applied to composed signals having the desired characteristics, and additionally may facilitate the application of frequency domain equalisation (128) in order to mitigate transmission impairments, including dispersion.

Abstract: A method of communicating digital information over a dispersive optical channel includes encoding the digital information into a plurality of data blocks, each of which includes a number of bits of the information. A time-varying electrical signal is generated which corresponds with each of said data blocks. The time-varying electrical signal is applied to an optical transmitter (122) to generate an optical signal which includes an asymmetrically amplitude limited transmitted signal modulated onto an optical carrier. The optical signal is then transmitted over the dispersive optical channel (106). At a receiving apparatus (104) the optical signal is detected to produce an electrical signal which corresponds with the asymmetrically amplitude limited transmitted signal.

Abstract: A system (100) for transmitting digital information includes a transmitting apparatus (102) for generating an optical signal bearing digital information, a dispersive optical channel (104), and a receiving apparatus (110) for receiving the optical signal. The dispersive optical channel (104) is disposed to convey the optical signal from the transmitting apparatus (102) to the receiving apparatus (110). The transmitting apparatus includes an encoder (114) for encoding digital information into a series of blocks, each including a plurality of data symbols corresponding with one or more bits of digital information. A signal generator (118) generates a time-varying signal corresponding with each of said blocks.

Abstract: A vessel includes a gas reservoir. The vessel also includes at least one gas outlet. The gas outlet includes an integral gas permeable membrane. A culture system includes the vessel as a first vessel. The first vessel is coupled to a second vessel that includes or otherwise contains a cell, a plant, an animal or the like.

Abstract: The invention provides a new approach which is better suited to FFT design as applied to multicarrier modulation systems such as OFDM. The signals are scaled so that overflow, rather than being completely avoided, occurs with low probability throughout the IFFT and FFT structures. The size of the error that results from an overflow depends on how overflow is handled in the DSP. To minimize the degradation, overflow should result in saturation of the value at the maximum positive or negative value option. This is equivalent to clipping the signal. Using the new technique, signals within the FFT structure are scaled to balance the effect of clipping and round-off. Clipping may result in comparatively large errors in a few signal values but because of the spreading effect of the FFT and because OFDM systems typically include error coding/correction, system performance depends on the total error or, in other words the total noise power, across all of the FFT outputs rather than on any individual value.

Abstract: Monoclonal antibodies specific for thyroxine (T.sub.4) are produced by two new and separate hybridoma cell lines. Combinations of the monoclonal antibodies from the two cell lines are used in an immunoassay for T.sub.4 of high accuracy over the range of T.sub.4 concentrations encountered in serum samples.

Abstract: Monoclonal antibodies specific for thyroxine (T.sub.4) are produced by two new and separate hybridoma cell lines. Combinations of the monoclonal antibodies from the two cell lines are used in an immunoassay for T.sub.4 of high accuracy over the range of T.sub.4 concentrations encountered in serum samples.