WIRELESS SENSOR READER
First Claim
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1. A wireless sensor reader comprising:
- a transmit circuit configured to generate at least one excitation pulse to cause a wireless sensor to emit at least one response signal wherein the excitation pulse is transmitted at a predetermined frequency determined during a period of time when said wireless sensor is not being sampled;
at least one antenna configured to transmit said excitation pulse and receive said response signal;
a phase-locked loop circuit configured to receive said response signal from said at least one antenna, said phase-locked loop circuit including a voltage-controlled oscillator configured to generate a count signal at a frequency related to said response signal frequency;
a first circuitry configured to sample the control voltage input of said voltage-controlled oscillator;
a second circuitry configured to generate a control voltage signal for input to said voltage-controlled oscillator; and
wherein said wireless sensor is configured to change its resonant frequency in proportion to at least one sensed parameter.
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Abstract
A wireless sensor reader is provided to interface with a wireless sensor. The wireless sensor reader transmits an excitation pulse to cause the wireless sensor to generate a ring signal. The wireless sensor reader receives and amplifies the ring signal and sends the signal to a phase-locked loop. A voltage-controlled oscillator in the phase-locked loop locks onto the ring signal frequency and generates a count signal at a frequency related to the ring signal frequency. The voltage-controlled oscillator is placed into a hold mode where the control voltage is maintained constant to allow the count signal frequency to be determined.
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Citations
20 Claims
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1. A wireless sensor reader comprising:
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a transmit circuit configured to generate at least one excitation pulse to cause a wireless sensor to emit at least one response signal wherein the excitation pulse is transmitted at a predetermined frequency determined during a period of time when said wireless sensor is not being sampled; at least one antenna configured to transmit said excitation pulse and receive said response signal; a phase-locked loop circuit configured to receive said response signal from said at least one antenna, said phase-locked loop circuit including a voltage-controlled oscillator configured to generate a count signal at a frequency related to said response signal frequency; a first circuitry configured to sample the control voltage input of said voltage-controlled oscillator; a second circuitry configured to generate a control voltage signal for input to said voltage-controlled oscillator; and wherein said wireless sensor is configured to change its resonant frequency in proportion to at least one sensed parameter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A wireless sensor reader comprising:
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a transmit circuit configured to generate at least one excitation pulse to cause a wireless sensor to emit at least one response signal corresponding to a sensed parameter value, wherein said excitation pulse is generated at a fixed frequency determined during before the excitation pulse is transmitted to the wireless sensor; at least one antenna configured to transmit said at least one excitation pulse and receive said at least one response signal; a receive circuit for amplifying said at least one received response signal; a digital sampling circuit for converting said at least one amplified received response signal to digital representation; a spectrum analysis circuitry for converting said digital representation of said at least one response signal to a frequency domain representation; and a frequency domain circuitry for processing of said frequency domain representation to determine said wireless sensor sensed parameter value. - View Dependent Claims (16, 17, 18, 19)
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20. A system for reading a wireless sensor comprising:
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a wireless sensor including at least one inductor and one capacitor configured to change its resonant frequency in proportion to at least one sensed parameter; and a reader for transmitting at least one excitation pulse to said wireless sensor and to receive at least one signal from said wireless sensor in response to said excitation pulse, wherein the reader includes; a digital sampling circuit for converting the at least one signal to a digital representation; a spectrum analysis circuitry for converting said digital representation of said at least one response signal to a frequency domain representation; and a frequency domain circuitry for processing of said frequency domain representation to determine said at least one sensed parameter.
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Specification