Sensing apparatus and method
First Claim
1. An inductive sensor for sensing a parameter, the inductive sensor comprising:
- a magnetic field generator operable to generate a magnetic field;
a receive aerial electromagnetically coupled to the magnetic field generator via a resonant circuit, said electromagnetic coupling being variable in dependence on the sensed parameter so that a sense signal induced in the receive aerial in response to a magnetic field generated by the magnetic field generator is representative of the sensed parameter, wherein the magnetic field generator is operable to generate a magnetic field comprising a first magnetic field component at a first frequency which is operable to induce resonance in the resonant circuit and a second magnetic field component at a second frequency which is not operable to induce resonance in the resonant circuit; and
a signal processor operable to process the sense signal to generate a signal component corresponding to a first component of the sense signal at said first frequency adjusted using a second component of the sense signal at the second frequency, and to determine a value representative of the sensed parameter using the signal component.
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Accused Products
Abstract
There is described an inductive sensor for sensing a parameter such as position. The inductive sensor includes: receive aerial which is electro-magnetically coupled to a magnetic field generator via a resonant circuit with the electromagnetic coupling varying in dependence upon the sensed parameter so that a sense signal induced in the receive aerial is representative of the sensed parameter. The magnetic field generator generates a magnetic field including a first magnetic field component at a first frequency which is operable to induce resonance in the resonant circuit and a second magnetic field component at a second frequency which is not operable to induce resonance in the resonant circuit. The signal processor processes the sense signal to generate a signal component corresponding to a first component of the sense signal at the first frequency adjusted using a second component of the sense signal at the second frequency so that a noise component of the first component of the sense signal is reduced, and determines a value representative of the sensed parameter using the signal component.
54 Citations
16 Claims
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1. An inductive sensor for sensing a parameter, the inductive sensor comprising:
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a magnetic field generator operable to generate a magnetic field; a receive aerial electromagnetically coupled to the magnetic field generator via a resonant circuit, said electromagnetic coupling being variable in dependence on the sensed parameter so that a sense signal induced in the receive aerial in response to a magnetic field generated by the magnetic field generator is representative of the sensed parameter, wherein the magnetic field generator is operable to generate a magnetic field comprising a first magnetic field component at a first frequency which is operable to induce resonance in the resonant circuit and a second magnetic field component at a second frequency which is not operable to induce resonance in the resonant circuit; and a signal processor operable to process the sense signal to generate a signal component corresponding to a first component of the sense signal at said first frequency adjusted using a second component of the sense signal at the second frequency, and to determine a value representative of the sensed parameter using the signal component. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An inductive sensor for sensing a parameter, the inductive sensor comprising:
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a receive aerial electromagnetically coupled to a magnetic field generator via a resonant circuit, said electromagnetic coupling being variable in dependence on the sensed parameter so that a sense signal induced in the receive aerial in response to a magnetic field generated by the magnetic field generator is representative of the sensed parameter, wherein the magnetic field generator is operable to generate a magnetic field comprising a first magnetic field component at a first frequency which is operable to induce resonance in the resonant circuit and a second magnetic field component at a second frequency which is not operable to induce resonance in the resonant circuit; and a signal processor operable to process the sense signal to generate a signal component corresponding to a first component of the sense signal at said first frequency adjusted using a second component of the sense signal at the second frequency to reduce a noise component of the first component of the sense signal, and to determine a value representative of the sensed parameter using the signal component.
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16. An inductive sensing method for sensing a parameter, the method comprising the steps of:
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generating a magnetic field comprising a first magnetic field component at a first frequency which is operable to induce resonance in a resonant circuit and a second magnetic field component at a second frequency which is not operable to induce resonance in the resonant circuit; and processing a sense signal induced in a receive aerial in response to a magnetic field generated by the magnetic field generator, wherein the receive aerial is electromagnetically coupled to the magnetic field via the resonant circuit with said electromagnetic coupling varying in dependence on the sensed parameter so that the sense signal is representative of the sensed parameter, wherein said processing step comprises generating a signal component corresponding to a first component of the sense signal at said first frequency adjusted using a second component of the sense signal at the second frequency, and determining a value representative of the sensed parameter using the signal component.
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Specification