Adaptive IIP2 calibration
First Claim
Patent Images
1. A radio frequency transceiver, comprising:
- a duplexer;
a transmitter coupled to the duplexer;
a receiver including a mixer, coupled to the duplexer, wherein the receiver receives a leaked signal comprising a transmit RF signal leaked through the duplexer; and
a calibration system, the calibration system includingan estimator, coupled to the transmitter and to the receiver, for calculating an estimate of second-order intermodulation distortion in the receiver as a result of second-order intermodulation distortion occurring in the mixer, wherein the estimator uses a live transmit signal from the transmitter as reference signal, anda controller, coupled to the estimator, for adjusting an input-related, second-order intercept (IIP2) point tuning port of the mixer, based on the estimate of second-order intermodulation distortion in the receiver, to reduce second-order intermodulation distortion in the receiver.
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Abstract
A radio frequency transceiver (102), including a transmitter (104), a duplexer (108) and a direct-conversion receiver (106) including a mixer (140 and 141). An IIP2 calibration system (170), coupled to the transceiver, includes an IIP2 coefficient estimator (172) for calculating an estimate of second-order distortion intermodulation distortion, and an IIP2 controller (174) for adjusting an IIP2 tuning port of the mixer in the receiver to minimize second-order distortion intermodulation distortion in the receiver that may be caused by the receiver receiving a transmit RF signal leaking through the duplexer.
28 Citations
15 Claims
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1. A radio frequency transceiver, comprising:
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a duplexer; a transmitter coupled to the duplexer; a receiver including a mixer, coupled to the duplexer, wherein the receiver receives a leaked signal comprising a transmit RF signal leaked through the duplexer; and a calibration system, the calibration system including an estimator, coupled to the transmitter and to the receiver, for calculating an estimate of second-order intermodulation distortion in the receiver as a result of second-order intermodulation distortion occurring in the mixer, wherein the estimator uses a live transmit signal from the transmitter as reference signal, and a controller, coupled to the estimator, for adjusting an input-related, second-order intercept (IIP2) point tuning port of the mixer, based on the estimate of second-order intermodulation distortion in the receiver, to reduce second-order intermodulation distortion in the receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A radio frequency transceiver, comprising:
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a duplexer; a transmitter coupled to the duplexer; a direct-conversion receiver including a mixer, coupled to the duplexer, wherein the receiver receives a leaked signal comprising a transmit RF signal leaked through the duplexer; circuitry that determines a transmit power output of the transmitter; circuitry that determines a received signal strength indication of the receiver; circuitry that determines a linear gain between baseband of the transmitter and baseband of the receiver; and a calibration system, including circuitry, coupled to baseband of the transmitter, that determines a filtered, delayed, amplitude squared version of a baseband transmit signal, circuitry that multiplies the filtered, delayed, amplitude squared version of a baseband transmit signal with the linear gain to produce a first signal, circuitry that compares the first signal with a baseband receive signal that includes a second-order intermodulation distortion product produced in the mixer from the leaked signal, wherein the circuitry that compares uses a version of a sign-sign least means squared optimization algorithm for estimating a value of an input-related, second-order intercept (IIP2) coefficient that is proportional to the second-order intermodulation distortion product produced in the mixer, and circuitry that produces, in response to results from the optimization algorithm, a tuning voltage for tuning an IIP2 port of the mixer to reduce the second-order intermodulation distortion occurring in the mixer. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification