Radio frequency data communications device
First Claim
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1. An apparatus for determining when frequency lock occurs relative to a desired frequency, the apparatus comprising:
- 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 first size;
said second circuitry configured to further increase the voltage applied to the voltage controlled oscillator after decreasing the voltage; and
said first circuitry configured to further provide a signal indicating that lock has occurred in response to the increase.
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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
16 Claims
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1. 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 first size;
said second circuitry configured to further increase the voltage applied to the voltage controlled oscillator after decreasing the voltage; and
said first circuitry configured to further provide a signal indicating that lock has occurred in response to the increase. - View Dependent Claims (2)
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3. 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;
decreasing the voltage applied to the voltage controlled oscillator using one or more steps of a second size smaller than the first size;
increasing the voltage applied to the voltage controlled oscillator after the decreasing and indicating that lock has occurred.
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4. 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;
means for increasing the voltage applied to the voltage controlled oscillator using one or more steps of a first size;
means for decreasing the voltage applied to the voltage controlled oscillator using one or more steps of a second size smaller than the first size;
means for increasing the voltage applied to the voltage controlled oscillator after the decreasing and means for indicating that lock has occurred responsive to the increasing after the decreasing.
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5. A method of determining when a phase lock loop achieves frequency lock relative to a desired frequency, the phase lock loop including a voltage controlled oscillator having a control node and oscillating at a frequency responsive to the voltage applied to the control node, the method comprising:
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adjusting the voltage on the control node in a first direction beyond the voltage that results in a lock;
subsequent to the adjusting in the first direction, adjusting the voltage on the control node in a second direction, opposite the first direction, overshooting the voltage that results in a lock;
subsequent to the adjusting in the second direction, adjusting the voltage on the control node in the first direction; and
providing a signal, indicating that frequency lock has been achieved, in response to the adjusting in the first direction after the adjusting in the second direction. - View Dependent Claims (6, 7)
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8. 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 that oscillates at a frequency responsive to voltage applied to the voltage controlled oscillator;
applying a voltage to the voltage controlled oscillator to produce a frequency of oscillation less than the desired frequency;
first increasing the voltage applied to the voltage controlled oscillator using one or more steps of a first size;
second increasing the voltage applied to the voltage controlled oscillator using one or more steps of a second size smaller than the first size, beyond the voltage appropriate for a lock;
decreasing the voltage applied to the voltage controlled oscillator, after the second increasing, using one or more steps of a third size smaller than the first size beyond the voltage appropriate for a lock;
increasing the voltage applied to the voltage controlled oscillator after the decreasing and providing a signal indicating that lock has occurred. - View Dependent Claims (9, 10)
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11. A method of determining when a phase lock loop achieves frequency lock relative to a desired frequency, the phase lock loop including a voltage controlled oscillator having a control node and oscillating at a frequency responsive to the voltage applied to the control node, the method comprising:
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increasing the voltage applied to the control node to a voltage above the voltage that results in the phase lock loop tracking the desired frequency;
decreasing the voltage applied to the control node to a voltage below the voltage that results in the phase lock loop tracking the desired frequency; and
increasing the voltage applied to the control node and indicating that frequency lock has been achieved in response to the increasing after the decreasing. - View Dependent Claims (12, 13, 14)
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15. A method of determining when frequency lock occurs relative to a desired frequency, in a communication system, the method comprising:
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receiving a reference timing signal via radio frequency;
providing a phase lock loop including a voltage controlled oscillator that oscillates at a frequency responsive to voltage applied to the voltage controlled oscillator, the phase lock loop being configured to track the reference timing signal;
applying a voltage to the voltage controlled oscillator to produce a frequency of oscillation less than the desired frequency;
first increasing the voltage applied to the voltage controlled oscillator using one or more steps of a first size;
second increasing the voltage applied to the voltage controlled oscillator using one or more steps of a second size smaller than the first size, beyond the voltage appropriate for a lock;
decreasing the voltage applied to the voltage controlled oscillator, after the second increasing, using one or more steps of a third size smaller than the first size beyond the voltage appropriate for a lock;
increasing the voltage applied to the voltage controlled oscillator after the decreasing and providing a signal indicating that lock has occurred. - View Dependent Claims (16)
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Specification