Abstract: An apparatus (20) for use in inductive sensing includes a loop antenna (26) and a signal generator (24) for driving the antenna, these forming a resonator circuit (22). The resonator circuit is drivable in a drive state in which the antenna is driven at resonance to thereby generate electromagnetic signals. The arrangement further includes a switching means (28) for switchably inhibiting the drive state of the antenna This allows in use controllable switching of the antenna in and out of the drive state to thereby control switching signal generation on and off.

Abstract: A physiological parameter inductive sensing system has a loop resonator which inductively couples with electromagnetic signals emitted from the body. The loop resonator forms part of an oscillator circuit, and negative feedback control is used to control the oscillator circuit, based on a measured oscillation amplitude. Within the feedback control loop, an analog to digital converter is used with a first number of bits (or trits), and successive outputs of the analog to digital converter are combined to derive an output value with a resolution of a second number of bits, greater than the first number of bits (or trits). The feedback control of the amplitude of the oscillator circuit is achieved using the output value.

Abstract: A system (8) and method is for extracting from sensed induction signals, component signals pertaining to different physiological phenomena in the body. A resonator circuit (10) is oscillated at a certain frequency to generate an alternating electromagnetic field which is applied to a body to be investigated. This field induces secondary eddy currents in the body which interact with the primary magnetic field and alter at least the frequency and amplitude of the resonator circuit oscillating current. These changes in the current characteristics, in particular the frequency and amplitude, are measured and provide first and second input signals. A system (8) or method is provided by embodiments of the invention which is arranged to receive these input signals. A multitude of different composite or fused signals are then generated by the system, each formed from a different linear combination ratio of the two input signals.

Abstract: A switching mechanism is for enabling use of an inductive sensing circuit (16) in association with a portable handheld device (14) having electromagnetic transmission functionality in a manner that avoids harmful interference of the electromagnetic transmissions of the portable device with the subject when medical sensing is being performed. In particular, embodiments provide a controller (12) arranged to control switching between two modes: a first mode in which at least a portion of the transmission functionality of the portable device is deactivated and concurrently the inductive sensing circuit is activated; and a second mode in which the electromagnetic transmission functionality of the portable device is fully activated, and the inductive sensing circuit is deactivated. Thus embodiments provide a means of toggling between two modes, the modes configured to avoid simultaneous inductive sensing and full-power electromagnetic transmission of the portable handheld device.

Abstract: An inductive sensing system (8) is for detecting bleeding (e.g. blood pools) in one or more regions of the body. The system comprises a resonator circuit (10) having at least one antenna (12) which is driven with an oscillatory drive signal to cause generation of electromagnetic signals for application to a body. The signals induce eddy currents in the body which generate secondary EM signals returned from the body. These interact with the resonator circuit by adding an additional component of inductance to the circuit. This inductance component varies depending upon the conductivity of the fluid in which the eddy current is induced. Blood has a different conductivity to other body fluids. The system is configured to detect presence of abnormal accumulations of blood based on the additional inductance component. The system generates a data output representative of the determination.

Abstract: An inductive sensing system (8) has a resonator circuit (10) with an antenna (12) for simultaneously applying electro-magnetic signals to a body and sensing secondary electromagnetic signals returned from the body. The system includes signal sensing means (30) which is configured to detect a measure indicative of an imaginary part of an additional inductance component added to the resonator circuit by the secondary electromagnetic signals but which does not measure the real part. In particular, the signal sensing means may be configured to detect a measure indicative of damping in the resonator circuit (e.g. a damping factor), and comprises no means for detecting any measure indicative of variations in a natural frequency of the resonator circuit.

Abstract: An inductive sensing system (8) is adapted to apply electromagnetic excitation signals into a body, the system comprising a resonator circuit (10) incorporating a loop antenna (12). The system senses signals returned back from the body with the same antenna, based on variation in electrical characteristics of the resonator circuit. The system is configured for separating signals received from different physiological sources within the body. This is performed based on detecting in the resonator circuit electrical characteristics indicative of both a real and an imaginary part of an additional inductance component added to the antenna by received electromagnetic signals. The separating the signals from different physiological sources is based on relative magnitudes of said detected real and imaginary inductance components added to the resonator circuit by the returned signals.