Preventing False Locks in a System that Communicates With an Implanted Wireless Sensor
First Claim
1. A method for identifying a false lock, comprising:
- generating an energizing signal with a first phase and a first frequency;
receiving a calibration signal;
determining a first phase difference between the calibration signal and the energizing signal;
based on the first phase difference adjusting the first phase of the energizing signal to reduce the first phase difference;
energizing a wireless sensor with an energizing signal having the first frequency;
receiving a sensor signal;
determining whether the sensor signal includes a predetermined beat frequency; and
if the sensor signal includes the predetermined beat frequency, then determining that the first frequency of the energizing signal corresponds to a false lock.
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Accused Products
Abstract
The present invention determines the resonant frequency of a wireless sensor by adjusting the phase and frequency of an energizing signal until the frequency of the energizing signal matches the resonant frequency of the sensor. The system energizes the sensor with a low duty cycle, gated burst of RF energy having a predetermined frequency. The system receives the ring down response of the sensor and determines the resonant frequency of the sensor, which is used to calculate a physical parameter. The system uses a pair of phase locked loops to adjust the phase and the frequency of the energizing signal. The system identifies false locks by detecting an unwanted beat frequency in the coupled signal, as well as determining whether the coupled signal exhibits pulsatile characteristics that correspond to a periodic physiological characteristic, such as blood pressure.
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Citations
32 Claims
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1. A method for identifying a false lock, comprising:
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generating an energizing signal with a first phase and a first frequency;
receiving a calibration signal;
determining a first phase difference between the calibration signal and the energizing signal;
based on the first phase difference adjusting the first phase of the energizing signal to reduce the first phase difference;
energizing a wireless sensor with an energizing signal having the first frequency;
receiving a sensor signal;
determining whether the sensor signal includes a predetermined beat frequency; and
if the sensor signal includes the predetermined beat frequency, then determining that the first frequency of the energizing signal corresponds to a false lock. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for identifying a false lock, comprising:
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energizing a wireless sensor with an energizing signal having a first frequency;
receiving a sensor signal;
sampling the sensor signal using multiple sampling points;
determining whether the sensor signal includes a predetermined beat frequency; and
if the sensor signal includes the predetermined beat frequency, then determining that the first frequency of the energizing signal corresponds to a false lock. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method for identifying a false lock, comprising:
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energizing a wireless sensor with an energizing signal having a first frequency;
receiving a sensor signal;
determining energy within the sensor signal for each of a plurality of predetermined frequency ranges;
comparing the energy in the predetermined frequency ranges to determine whether the sensor signal includes pulsatile characteristics based on a periodic physiological characteristic; and
if the sensor signal does not include pulsatile characteristics based on periodic physiological characteristic, then determining that the first frequency of the energizing signal corresponds to a false lock. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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23. A system for identifying a false lock, comprising:
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an energizing signal generator for generating an energizing signal;
a receiver for receiving a sensor signal from a wireless sensor;
a time to frequency domain transform module for transforming a signal corresponding to a change of frequency of the energizing signal;
a comparison module for comparing energy in a lower frequency range with energy in a higher frequency range over a predetermined time period to determine whether the signal includes pulsatile characteristics based on a periodic physiological characteristic; and
an output module for identifying a false lock when the comparison module determines that the signal does not include pulsatile characteristics based on the periodic physiological characteristic. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32)
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Specification