Loosely-coupled oscillator
First Claim
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1. An oscillator comprising:
- a sensor circuit comprising an inductor and a capacitor, the sensor circuit being adapted to resonate at a resonant frequency;
an electronic device physically disconnected from the sensor circuit, the electronic device comprising an input and an output, the input being connected to electrical ground through an electronic device coil, the electronic device being adapted to amplify an input signal to produce an output signal at the electronic device output, the electronic device comprising;
an amplifier stage adapted to amplify the input signal, wherein the amplifier stage comprises circuitry adapted to provide a high amplifier stage input impedance to prevent the electronic device coil from changing the resonant frequency of the sensor circuit; and
a feedback network connected to an input of the amplifier and an output of the amplifier stage and adapted to provide a feedback for the amplifier stage, the feedback network comprising a pulse generator configured to provide a start-up pulse and a high impedance for the feedback network at the input of the amplifier stage; and
wherein the sensor circuit and the electronic device are electromagnetically coupled to obtain the input signal at the electronic device input, the output signal having characteristics associated with the resonant frequency of the sensor circuit, the characteristics comprising a frequency that is the same as the resonant frequency.
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Abstract
Certain embodiments of the present invention provide a loosely-coupled oscillator including a circuit and an electronic device that are not physically connected. The electronic device may include an amplifier for amplifying a signal to produce an output signal and include a wire connected to an input of the amplifier. The wire can be electromagnetically coupled to the circuit that is physically disconnected from the electronic device. The output signal can be produced at an output of the amplifier without transmitting an excitation signal from the electronic device to the circuit and when the wire is electromagnetically coupled to the circuit.
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Citations
19 Claims
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1. An oscillator comprising:
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a sensor circuit comprising an inductor and a capacitor, the sensor circuit being adapted to resonate at a resonant frequency; an electronic device physically disconnected from the sensor circuit, the electronic device comprising an input and an output, the input being connected to electrical ground through an electronic device coil, the electronic device being adapted to amplify an input signal to produce an output signal at the electronic device output, the electronic device comprising; an amplifier stage adapted to amplify the input signal, wherein the amplifier stage comprises circuitry adapted to provide a high amplifier stage input impedance to prevent the electronic device coil from changing the resonant frequency of the sensor circuit; and a feedback network connected to an input of the amplifier and an output of the amplifier stage and adapted to provide a feedback for the amplifier stage, the feedback network comprising a pulse generator configured to provide a start-up pulse and a high impedance for the feedback network at the input of the amplifier stage; and wherein the sensor circuit and the electronic device are electromagnetically coupled to obtain the input signal at the electronic device input, the output signal having characteristics associated with the resonant frequency of the sensor circuit, the characteristics comprising a frequency that is the same as the resonant frequency. - View Dependent Claims (2, 3)
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4. An electronic device, comprising:
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an amplifier for amplifying a signal to produce an output signal, the amplifier comprising an input and an output; and a wire connected to the input of the amplifier, the wire configured to be electromagnetically coupled to a circuit that is physically disconnected from the electronic device and that has a resonant frequency, wherein the wire is capable of sensing a presence of the circuit when the wire is located in proximity to the circuit without transmitting an excitation signal from the wire to the circuit, wherein the output signal is produced at the output of the amplifier when the wire is electromagnetically coupled to the circuit, the output signal having characteristics associated with the resonant frequency of the circuit. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11)
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12. A method comprising:
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sensing a presence of a circuit by a wire by locating the wire in proximity to the circuit and without transmitting an excitation signal from the wire to the circuit, the circuit being physically disconnected from the wire, wherein the circuit has a resonant frequency and the wire is connected to an amplifier input; producing an input signal at the amplifier input when the impedance of the wire increases as the wire is brought in proximity to the circuit, wherein the input signal is produced without transmitting an excitation signal from the wire to the circuit, and wherein the input signal has characteristics associated with the resonant frequency of the circuit; and producing an output signal at an amplifier output by amplifying the input signal, the output signal having characteristics associated with the resonant frequency of the circuit. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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Specification