University of Cape Town

The University of Sydney

The University of Cape Town Research Contracts and Intellectual Property Services

Jonathan Craig Tapson

Ralph Etienne-Cummings

David Holder

Andre Van Schaik

Francesco V G Tenore

Fopefulu O Folowosele

Alistair Lee McEwan

Mark Philip Vismer

A method is provided for taking electrical impedance tomography measurements using multiple electrodes located at selected positions external to a volume of a subject body. Multiple orthogonal or near-orthogonal signals are introduced simultaneously by way of selected different electrodes and resultant predetermined responses (if any) at receiving electrodes are recorded or determined. The signals are encoded using the technique of code division multiplexing and received signals at each receiving electrode are cross-correlated with original signals to determine the contribution of each original signal to a composite received signal. The invention also relates to apparatus suitable for use in applying a method.

System and method for conducting multiplexed electrical impedance tomography

A sub-circuit for facilitating the synchronization of event-based samples of signals in a cross-correlation circuit utilizing event-based sampling is provided. The sub-circuit alternatively integrates one of the signals to be cross-correlated and alternates between the signals in response to the output of a hysteretic comparator. The invention extends to a method of manipulating the input signals to a cross-correlation circuit utilizing event-based sampling so-as to facilitate the synchronization of the event-based samples of the signals.

Cross-correlation of signals using event-based sampling

A position sensor comprising a primary winding () for generating a magnetic flux, a first secondary winding () the number of turns of which increases in one direction, a second secondary winding () the number of turns of which increases in the opposite direction to that of the first secondary winding. Both secondary windings () are subjected to the magnetic flux generated by the primary winding () whereby voltages are induced in the secondary windings. The sensor further comprises an element movable with respect to the secondary windings. The element is of a magnetic or conductive material and distorts, in its vicinity, the magnetic flux generated by the primary winding (). By providing third and fourth secondary windings at right angles to the first and secondary windings it is possible to detect position in two dimensions.

Inductive position sensors with secondary windings with increased or decreased number of turns

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Cape Town, South Africa

Jonathan Craig Tapson