Radio frequency data communications device
First Claim
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1. A method of determining when frequency lock occurs relative to a desired frequency, the method comprising:
- providing a phase lock loop including a voltage controlled oscillator configured to oscillate at a frequency which varies responsive to a voltage applied to the voltage controlled oscillator;
applying the voltage to the voltage controlled oscillator to produce a frequency of oscillation less than the desired frequency;
increasing the voltage applied to the voltage controlled oscillator using one or more steps of a first size;
increasing the voltage applied to the voltage controlled oscillator using one or more steps of a second size smaller than the first size;
decreasing the voltage applied to the voltage controlled oscillator using one or more steps of a third size smaller than the second size;
increasing the voltage applied to the voltage controlled oscillator using a step of the third size; and
indicating that lock has occurred in response to the increase of the step of the third size.
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Abstract
A radio frequency identification device comprises an integrated circuit including a receiver, a transmitter, and a microprocessor. The receiver and transmitter together define an active transponder. The integrated circuit is preferably a monolithic single die integrated circuit including the receiver, the transmitter, and the microprocessor. Because the device includes an active transponder, instead of a transponder which relies on magnetic coupling for power, the device has a much greater range.
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Citations
3 Claims
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1. A method of determining when frequency lock occurs relative to a desired frequency, the method comprising:
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providing a phase lock loop including a voltage controlled oscillator configured to oscillate at a frequency which varies responsive to a voltage applied to the voltage controlled oscillator;
applying the voltage to the voltage controlled oscillator to produce a frequency of oscillation less than the desired frequency;
increasing the voltage applied to the voltage controlled oscillator using one or more steps of a first size;
increasing the voltage applied to the voltage controlled oscillator using one or more steps of a second size smaller than the first size;
decreasing the voltage applied to the voltage controlled oscillator using one or more steps of a third size smaller than the second size;
increasing the voltage applied to the voltage controlled oscillator using a step of the third size; and
indicating that lock has occurred in response to the increase of the step of the third size.
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2. An apparatus for determining when frequency lock occurs relative to a desired frequency, the apparatus comprising:
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a phase lock loop including a voltage controlled oscillator configured to oscillate at a frequency which varies responsive to a voltage applied to the voltage controlled oscillator;
means for applying the voltage to the voltage controlled oscillator to produce a frequency of oscillation less than the desired frequency;
first means for increasing the voltage applied to the voltage controlled oscillator using one or more steps of a first size;
said first means further increasing the voltage applied to the voltage controlled oscillator using one or more steps of a second size smaller than the first size;
second means for decreasing the voltage applied to the voltage controlled oscillator using one or more steps of a third size smaller than the second size;
said second means further increasing the voltage applied to the voltage controlled oscillator using a step of the third size; and
said first means further indicating that lock has occurred in response to the increase of the step of the third size.
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3. An apparatus for determining when frequency lock occurs relative to a desired frequency, the apparatus comprising:
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a phase lock loop including a voltage controlled oscillator configured to oscillate at a frequency which varies depending on a voltage applied to the voltage controlled oscillator;
circuitry configured to apply the voltage to the voltage controlled oscillator to produce a frequency of oscillation less than the desired frequency;
first circuitry configured to increase the voltage applied to the voltage controlled oscillator using one or more steps of a first size;
said first circuitry configured to further increase the voltage applied to the voltage controlled oscillator using one or more steps of a second size smaller than the first size;
second circuitry configured to decrease the voltage applied to the voltage controlled oscillator using one or more steps of a third size smaller than the second size;
said second circuitry configured to further increase the voltage applied to the voltage controlled oscillator using a step of the third size; and
said first circuitry configured to further provide a signal indicating that lock has occurred in response to the increase of the step of the third size.
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Specification