Phase-Locked Loop Based Controller for Adjusting an Adaptive Continuous-Time Filter
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Abstract
A direct conversion radio-frequency (RF) receiver includes a controller and an adaptive continuous-time filter. The adaptive continuous-time filter receives a multiple-bit control signal generated by the controller to adjust a characteristic of the continuous-time filter. The controller generates the multiple-bit control signal in response to process variation in the semiconductor material used to implement the controller and the adaptive continuous-time filter. A method for tuning an adaptive continuous-time filter comprises determining a RC time constant, converting the RC time constant to a digital word, comparing a select bit of the digital word to a respective bit of a predetermined reference word to generate a control bit, applying the control bit to an adjustable element to modify the RC time constant, repeating the determining, converting, comparing and applying steps until the control bits generate an output word and providing the output word to the adaptive continuous-time filter.
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Citations
40 Claims
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1-20. -20. (canceled)
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21. A direct conversion radio-frequency receiver, comprising:
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a replicator having a first array of elements, the replicator generating a first signal having a frequency responsive to a time constant a digitizer configured to receive the first signal from the replicator, the digitizer generating a control signal responsive to the first signal; and a word generator configured to receive the control signal and a reference signal, the word generator generating an output word responsive to process variation in the semiconductor material used to implement the replicator. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29)
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30. A method for tuning an adaptive continuous-time filter, comprising:
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generating a digital word responsive to a time constant; comparing a select bit of the digital word to a respective bit of a reference word to generate a control bit; applying the control bit to an adjustable element to modify the time constant; repeating the generating, comparing and applying steps to generate an output word having a desired number of bits; and providing the output word to an adaptive continuous-time filter. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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Specification