Resonant Circuits
First Claim
1. A controllable electric resonator comprising an inductor coupled to a first capacitor to form a resonant circuit, the resonator further comprising a controllable element, a second capacitor controllable coupled across said first capacitor by said controllable element, and a control device to control said controllable element such that a total effective capacitance of said first and second capacitor varies over a duty cycle of an oscillatory signal on said resonator.
2 Assignments
0 Petitions
Accused Products
Abstract
Embodiments of the invention relate to resonant circuits; particularly but not exclusively the embodiments relate to resonant circuits in RPID (radio frequency identification) responsive to a wide frequency range. A controllable electric resonator comprising an inductor coupled to a first capacitor to form a resonant circuit, the resonator further comprising a controllable element, a second capacitor controllable coupled across said first capacitor by said controllable element, and a control device to control said controllable element such that a total effective capacitance of said first and second capacitor varies over a duty cycle of an oscillatory signal on said resonator.
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Citations
46 Claims
- 1. A controllable electric resonator comprising an inductor coupled to a first capacitor to form a resonant circuit, the resonator further comprising a controllable element, a second capacitor controllable coupled across said first capacitor by said controllable element, and a control device to control said controllable element such that a total effective capacitance of said first and second capacitor varies over a duty cycle of an oscillatory signal on said resonator.
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10. (canceled)
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11. (canceled)
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12. A controllable electric resonator comprising a resonant circuit and a system for controlling the amplitude of oscillations on the resonant circuit, when the resonant circuit is driven by an oscillatory signal, the apparatus comprising:
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means for applying a reactive element to said resonant circuit with a variable coupling; and means for varying said coupling over a cycle of said oscillatory signal to control said amplitude of oscillations.
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- 13. A method of controlling a resonant frequency of a controllable electric resonator to substantially match said resonant frequency to a frequency of an external waveform, the controllable electric resonator comprising an inductance coupled to a capacitance, the capacitance having a switched component of capacitance, the method comprising controlling a duty cycle of said switched component of capacitance in response to a signal level of a waveform of an oscillation of said resonant circuit.
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20. (canceled)
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21. (canceled)
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22. (canceled)
- 23. A controllable electronic resonator having a controllable resonant circuit and incorporated in an RFID tag, the resonant circuit comprising an inductance coupled to a capacitance, the capacitance having a switched component of capacitance, wherein said controllable resonant circuit is configured to automatically control a duty cycle of said switched component of capacitance to select one of a plurality of frequencies of operation of said tag in response to an interrogating rf field.
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24. A controllable electric LC (inductor-capacitor) resonant circuit comprising an inductor, a primary capacitive path, and at least one other secondary capacitive path that is coupled into the resonance with a variable duty cycle;
- and wherein the circuit response frequency, which is dependent on the duty cycle, matches to a stimulus frequency.
- View Dependent Claims (25, 26, 27, 46)
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30-40. -40. (canceled)
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42. A controllable electric resonator comprising a resonant circuit and a system for controlling the amplitude of oscillations on the resonant circuit, when the resonant circuit is driven by an oscillatory signal, the apparatus comprising:
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means for applying a reactive element to said resonant circuit with a variable coupling; and means for varying said coupling over a cycle of said oscillatory signal to control said amplitude of oscillations.
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- 44. A controllable electronic resonator including a circuit for controlling a resonant frequency of the resonator to substantially match said resonant frequency to a frequency of an external waveform, the resonator comprising an inductance coupled to a capacitance, the capacitance having a switched component of capacitance, the circuit comprising means for controlling a duty cycle of said switched component of capacitance in response to a signal level of a waveform of an oscillation of said resonator.
Specification