Abstract: Examples provide a multilevel switched-mode ultrasound transmitter comprising a first push-pull transistor arrangement comprising first and second drive transistors, third and fourth additional switched transistors, each arranged as a bidirectional load switch with a one of the first and second drive transistors, wherein the first drive transistor and associated third additional switched transistor operate in series as a first arm of the first push-pull transistor arrangement, and the second drive transistor and associated fourth additional switched transistor operate in series as a second arm of the first push-pull transistor arrangement, wherein each arm is coupled between a respective polarity instance of a first bipolar drive voltage supply and a common output.

Abstract: An apparatus and methods for determining the position of an elongate structure. A number of magnetic field sensors arranged at fixed spacing, each sensor being arranged to sense a magnetic field of a remote structure induced by the Earth's magnetic field in at least two orthogonal directions. In use, the magnetic field sensors are arranged remotely of an elongate structure having a longitudinal axis, such that the magnetic field sensors are spaced in a lateral direction relative to said longitudinal axis. An angular spacing for the magnetic field sensors about the longitudinal axis is determined according to the magnetic field readings in the two orthogonal directions and a distance between one or more of said magnetic field sensors and said elongate structure is determined based on said angular spacing determination.

Abstract: The disclosed technology relates to imaging catheters. A method is provided that includes: receiving, from a plurality of transducers disposed on a catheter probe, a corresponding plurality of analog signals; selectively sampling the plurality of analog signals; multiplexing to produce a sequence of samples; and transmitting the sequence of samples to a receiver circuit. The receiver circuit includes a clock; an analog to digital converter (ADC) in communication with the clock; and a sampling phase correction circuit in communication with the clock and the ADC. The method further includes: determining optimum sampling times based on measured signal delays associated with the system; adjusting a phase of the clock based on the measured signal delays; and communicating the phase-adjusted clock to the transmitter circuit for the selective sampling of the analog signals. Certain embodiments of the disclosed technology may further be utilized in conjunction with beamforming.

Abstract: An ultrasound generator having a signal generator; and to generate a pulsed drive signal from a modulating signal, the pulsed drive signal having at least a zero output level, a positive output level and a negative output level. The position and width of pulses are defined by at least first and second switching angles per half cycle of the modulating signal. In part of the range of the modulating signal one switching angle increases while the other switching angle decreases simultaneously such that the fundamental frequency of the pulsed drive signal increases or decreases with the modulating signal and such that a selected harmonic component of the generated pulsed drive signal is maintained below a first threshold. A transducer is arranged to generate ultrasound in response to the pulsed drive signal.

Abstract: An apparatus and methods for determining the position of an elongate structure. A number of magnetic field sensors arranged at fixed spacing, each sensor being arranged to sense a magnetic field of a remote structure induced by the Earth's magnetic field in at least two orthogonal directions. In use, the magnetic field sensors are arranged remotely of an elongate structure having a longitudinal axis, such that the magnetic field sensors are spaced in a lateral direction relative to said longitudinal axis. An angular spacing for the magnetic field sensors about the longitudinal axis is determined according to the magnetic field readings in the two orthogonal directions and a distance between one or more of said magnetic field sensors and said elongate structure is determined based on said angular spacing determination.

Abstract: The invention concerns structural integrity assessment apparatus for determining stress concentration zones in a structure, such as a pipeline. The apparatus allows particularly to detect defects in buried pipelines using magnetometric surveying where anomalies in the magnetic field around the pipelines are detected. The appar-atus has a plurality of triaxial magnetic field sensors, each sensor being arranged to measure magnetic field components in a plurality of directions. A support is provided to maintain said sensors in a predetermined relative spacing and orientation. The support is moveable relative to a structure under assessment in use and may be portable. Three or more magnetic field sensors are provided which may be arranged in a linear, two-dimensional or three-dimensional array. The ap-paratus may include position determining means, such as a global positioning system (GPS), so that stress concentration zones can be located on the structure.

Abstract: The invention concerns structural integrity assessment apparatus for determining stress concentration zones in a structure, such as a pipeline. The apparatus allows particularly to detect defects in buried pipelines using magnetometric surveying where anomalies in the magnetic field around the pipelines are detected. The apparatus has a plurality of triaxial magnetic field sensors, each sensor being arranged to measure magnetic field components in a plurality of directions. A support is provided to maintain said sensors in a predetermined relative spacing and orientation. The support is moveable relative to a structure under assessment in use and may be portable. Three or more magnetic field sensors are provided which may be arranged in a linear, two-dimensional or three-dimensional array. The apparatus may include position determining means, such as a global positioning system (GPS), so that stress concentration zones can be located on the structure.

Abstract: The invention concerns a structural integrity assessment system and method for determining stress concentration zones in a structure, such as a pipeline. The invention comprises a magnetic field sensor array arranged to be moved relative to the structure in a known direction. A controller is provided for recording one or more magnetic field readings taken by the magnetic field sensor array at different locations in the direction of movement thereof. A processor is arranged to identify one or more feature within said values, said feature being indicative of a region of reduced structural integrity in the structure. The processor also receives a data input for a further parameter corresponding to the location of the sensor array and compares the feature with the further parameter in order to verify that said feature corresponds to a region of reduced structural integrity for the structure.

Abstract: An ultrasound generator having a signal generator; and to generate a pulsed drive signal from a modulating signal, the pulsed drive signal having at least a zero output level, a positive output level and a negative output level. The position and width of pulses are defined by at least first and second switching angles per half cycle of the modulating signal. In part of the range of the modulating signal one switching angle increases while the other switching angle decreases simultaneously such that the fundamental frequency of the pulsed drive signal increases or decreases with the modulating signal and such that a selected harmonic component of the generated pulsed drive signal is maintained below a first threshold. A transducer is arranged to generate ultrasound in response to the pulsed drive signal.

Abstract: The invention concerns a structural integrity assessment system and method for determining stress concentration zones in a structure, such as a pipeline. The invention comprises a magnetic field sensor array arranged to be moved relative to the structure in a known direction. A controller is provided for recording one or more magnetic field readings taken by the magnetic field sensor array at different locations in the direction of movement thereof. A processor is arranged to identify one or more feature within said values, said feature being indicative of a region of reduced structural integrity in the structure. The processor also receives a data input for a further parameter corresponding to the location of the sensor array and compares the feature with the further parameter in order to verify that said feature corresponds to a region of reduced structural integrity for the structure.

Abstract: The invention concerns structural integrity assessment apparatus for determining stress concentration zones in a structure, such as a pipeline. The apparatus allows particularly to detect defects in buried pipelines using magnetometric surveying where anomalies in the magnetic field around the pipelines are detected. The apparatus has a plurality of triaxial magnetic field sensors, each sensor being arranged to measure magnetic field components in a plurality of directions. A support is provided to maintain said sensors in a predetermined relative spacing and orientation. The support is moveable relative to a structure under assessment in use and may be portable. Three or more magnetic field sensors are provided which may be arranged in a linear, two-dimensional or three-dimensional array. The apparatus may include position determining means, such as a global positioning system (GPS), so that stress concentration zones can be located on the structure.

Abstract: The invention relates to a method and apparatus for use in the channel estimating in a manner which reduces Bit Error Rate (BER) and/or Mean Square Error (MSE) and allows the channel estimation to be performed in an efficient manner but with reduced complexity. The method utilizes two phases, the first of which includes locating an optimum regularization parameters range from an initially larger range; and a second phase of obtaining optimum channel estimates from a Tikhonov regularized least squares solution using the optimum regularization parameters range located from the first phase.

Abstract: The invention relates to apparatus for the receipt of digital data which is transmitted as a data signal from a remote location and a method by which the receiving apparatus can be designed with a configuration to improve the ability to receive the data signal. The design of the configuration is generated with reference to at least one decision metric which is adapted to suit the known characteristics of the data signal which is being received.

Abstract: The invention relates to apparatus for the receipt of digital data which is transmitted as a data signal from a remote location and a method by which the receiving apparatus can be designed with a configuration to improve the ability to receive the data signal. The design of the configuration is generated with reference to at least one decision metric which is adapted to suit the known characteristics of the data signal which is being received.

Abstract: The invention relates to a method and apparatus for use in the channel estimating in a manner which reduces Bit Error Rate (BER) and/or Mean Square Error (MSE) and allows the channel estimation to be performed in an efficient manner but with reduced complexity. The method utilises two phases, the first of which includes locating an optimum regularisation parameters range from an initially larger range; and a second phase of obtaining optimum channel estimates from a Tikhonov regularized least squares solution using the optimum regularisation parameters range located from the first phase.

Abstract: Catheter-based devices for enhancing the local delivery of drugs, pharmaceuticals, plasmids, genes, and other agents into the wall tissues of tubular compartments of the living body. One catheter device provides an electrical driving force that can increase the rate of migration of drugs and other therapeutic agents out of a polymer matrix into body tissues and cells using iontophoresis only. Another device uses iontophoresis only, electroporation only, or combined iontophoresis and electroporation. In the latter device, the two procedures may be applied sequentially in any order without removing or repositioning the catheter.