Calibration for a tunable RF filter structure
First Claim
1. A radio frequency (RF) front-end circuitry, comprising:
- a tunable RF filter structure comprising a pair of weakly coupled resonators, wherein the tunable RF filter structure is tunable to define a transfer function with a passband;
a calibration circuit comprising a replica resonator and configured to;
shape the passband so that the passband defines a center frequency near a target center frequency using the replica resonator;
detect a phase difference between the pair of weakly coupled resonators at the target center frequency; and
adjust the phase difference between the pair of weakly coupled resonators at the target center frequency so as to reduce a frequency displacement between the center frequency of the passband and the target center frequency.
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Accused Products
Abstract
Embodiments of radio frequency (RF) front-end circuitry are disclosed where the RF front-end circuitry includes a tunable RF filter structure and a calibration circuit. The tunable RF filter structure includes (at least) a pair of weakly coupled resonators and defines a transfer function with a passband. The calibration circuit is configured to shape the passband so that the passband defines a center frequency. Additionally, the calibration circuit is configured to detect a phase difference at the target center frequency between the pair of weakly coupled resonators and adjust the phase difference of the pair of weakly coupled resonators at the target center frequency so as to reduce a frequency displacement between the center frequency of the passband and the target center frequency. In this manner, the calibration circuit calibrates the tunable RF filter structure to correct for errors in the center frequency of the passband due to component manufacturing variations.
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Citations
26 Claims
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1. A radio frequency (RF) front-end circuitry, comprising:
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a tunable RF filter structure comprising a pair of weakly coupled resonators, wherein the tunable RF filter structure is tunable to define a transfer function with a passband; a calibration circuit comprising a replica resonator and configured to; shape the passband so that the passband defines a center frequency near a target center frequency using the replica resonator; detect a phase difference between the pair of weakly coupled resonators at the target center frequency; and adjust the phase difference between the pair of weakly coupled resonators at the target center frequency so as to reduce a frequency displacement between the center frequency of the passband and the target center frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. Radio frequency (RF) front-end circuitry comprising:
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a tunable RF filter structure comprising a pair of weakly coupled resonators, wherein the tunable RF filter structure is tunable to define a transfer function with a passband; and a calibration circuit configured to; shape the passband so that the passband defines a center frequency; detect a phase difference between the pair of weakly coupled resonators at the target center frequency; and adjust the phase difference between the pair of weakly coupled resonators at the target center frequency to; reduce a frequency displacement between the center frequency of the passband and the target center frequency; and reduce a phase displacement between the phase difference at the target center frequency and a first target phase difference at the target center frequency, wherein the first target phase difference at the target center frequency has a magnitude of 90 degrees.
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26. A calibration method for a tunable radio frequency (RF) filter structure, comprising:
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shaping a passband using a replica resonator so that a center frequency of the passband is near a target center frequency, wherein the tunable RF filter structure has a transfer function that defines the passband; detecting a phase difference at the target center frequency between a pair of weakly coupled resonators in the tunable RF filter structure; and adjusting the phase difference between the pair of weakly coupled resonators at the target center frequency so as to reduce a frequency displacement between the center frequency of the passband and the target center frequency.
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Specification