Abstract: A mobile wireless communications device includes a transceiver, an auxiliary receiver and a controller. The transceiver includes a transmitter and a receiver. The transmitter upconverts a transmit baseband modulated signal and generates an RF modulated signal having a transmit impairment. The auxiliary receiver is coupled to the transmitter and downconverts the RF modulated signal and generates a receive baseband modulated signal having a receive impairment therein spectrally separated from the transmit impairment. The controller is coupled to the transmitter and the auxiliary receiver and estimates the transmit impairment while ignoring the receive impairment based on comparing the transmit baseband modulated signal with the receive baseband modulated signal. The controller generates an impairment compensation signal based upon the estimated transmit impairment.

Abstract: A mobile wireless communications device includes a portable housing, a transmitter carried by the portable housing and configured to modulate an input signal, and an adjustable impedance matching network coupled downstream from the transmitter. An antenna is coupled downstream from the adjustable impedance matching network, and a non-directional coupler is coupled between the adjustable impedance matching network and the antenna. A feedback receiver is coupled to the non-directional coupler to generate a feedback signal. A controller is configured to control the adjustable impedance matching network based upon the input signal and the feedback signal.

Abstract: A full duplex transceiver has cancellation circuitry that includes an auxiliary receiver and an auxiliary transmitter. More specifically, an analog received signal that includes transmission signal leakage is provided to a low noise amplifier (LNA), which then provides its output to a main receiver and the auxiliary receiver. The auxiliary receiver includes a portion operable to convert the received signal from the analog domain to the digital domain. The auxiliary receiver additionally includes a cancellation processor that determines the transmission signal leakage and generates a signal based on the determined leakage. This signal generated by the auxiliary receiver is provided to the auxiliary transmitter, which converts the digital signal back to the analog domain and generates a cancellation signal. The analog cancellation signal is fed back and added to the received signal at the input of the LNA.

Abstract: System and method for improving a digital PLL's performance by making fine grained adjustments to the loop gain. A preferred embodiment comprises a plurality of loop gain adjustors (such as loop gain adjustors 605, 606, 607, and 608) that can incrementally adjust the loop gain. The incrementally adjusted loop gains are sequentially brought on-line so that the loop gain of the digital PLL is slowly decreased. By slowly decreasing the loop gain, the digital PLL is less perturbed by smaller noise transients that would take time to settle. Hence, the digital PLL can quickly acquire a signal and then decrease its loop gain and hence its bandwidth when it only needs to track a signal. The reduced bandwidth also reduces the overall noise in the digital PLL that is due to the reference noise contribution.

Abstract: Methods and apparatus for canceling distortion in full-duplex transceivers are disclosed. Some example methods to reduce distortion in a full-duplex transceiver include generating a first digital signal, generating a first analog signal based on the first digital signal for transmission over a full-duplex channel, receiving a second analog signal via the full-duplex channel, and generating a second digital signal based on the second analog signal, wherein the second digital signal includes coupling distortion based on the first analog signal. The example methods further include generating an adaptive filter signal based on the first digital signal, and reducing the coupling distortion from the second digital signal by subtracting the adaptive filter signal from the second digital signal.

Abstract: A communications device may include In-phase (I) power amplifiers configured to generate I amplified signals, Quadrature (Q) power amplifiers configured to generate Q amplified signals, an I controller coupled to the I power amplifiers and configured to selectively enable some of the I power amplifiers, and a Q controller coupled to the Q power amplifiers and configured to selectively enable some of the Q power amplifiers. The communications device may also include a power combiner configured to combine the I amplified signals and the Q amplified signals in a combined amplified signal, and an antenna coupled to the power combiner.

Abstract: A communications device may include an In-phase (I) power amplifier configured to generate an I amplified signal, a Quadrature (Q) power amplifier configured to generate a Q amplified signal, an I digital-to-analog converter (DAC) configured to generate an I signal, and a Q DAC configured to generate a Q signal. The communications device may also include an I power supply circuit coupled to the I power amplifier and to the I DAC and configured to cause the I power amplifier to modulate an I carrier signal into the I amplified signal based upon the I signal, a Q power supply circuit coupled to the Q power amplifier and to the Q DAC and configured to cause the Q power amplifier to modulate a Q carrier signal into the Q amplified signal based upon the Q signal, and at least one antenna coupled to the I and Q power amplifiers.

Abstract: A communications device may include In-phase (I) power amplifiers configured to respectively generate I amplified signals, Quadrature (Q) power amplifiers configured to respectively generate Q amplified signals, I antennas respectively coupled to the I power amplifiers, and Q antennas respectively coupled to the Q power amplifiers. The communications device may also include an I controller coupled to the I power amplifiers and configured to selectively enable some of the I power amplifiers, and a Q controller coupled to the Q power amplifiers and configured to selectively enable some of the Q power amplifiers.

Abstract: An electronic device includes an input configured to receive at least one baseband input signal and at least one mixer downstream from the input. The electronic device also includes a phase-locked loop (PLL) including a voltage controlled oscillator (VCO) and a phase detector coupled thereto, the VCO coupled to the at least one mixer. A power amplifier is downstream from the at least one mixer and generates at least one aggressing signal that would otherwise generate an output pull of the VCO. The electronic device also includes a VCO pulling compensation circuit coupled to the input and the VCO and configured to compensate the VCO for the output pull based upon the at least one baseband input signal and the at least one aggressing signal.

Abstract: A mobile wireless communications device includes a portable housing, a transmitter carried by the portable housing and configured to modulate an input signal, and an adjustable impedance matching network coupled downstream from the transmitter. An antenna is coupled downstream from the adjustable impedance matching network, and a non-directional coupler is coupled between the adjustable impedance matching network and the antenna. A feedback receiver is coupled to the non-directional coupler to generate a feedback signal. A controller is configured to control the adjustable impedance matching network based upon the input signal and the feedback signal.

Abstract: Methods, apparatus, and articles of manufacture are described for improving distortion performance and for direct current offset cancellation in receivers. In one example, a method of improving distortion in a receiver includes determining a direct current (DC) amplitude of an offset signal, generating the offset signal, and providing the offset signal to an output of a mixer to improve the distortion performance of the mixer.

Abstract: Predistortion methods and apparatus for transmitter linearization in a communication transceiver are disclosed.

Abstract: A method for tuning a transmitter in order to improve impedance matching to an antenna or to intermediate radio frequency stages uses an error detector that senses a deviation of the amplitude or phase angle of a load current of a power amplifier driver or of a power amplifier. A controller calculates a correction and dynamically adjusts tunable transmitter parameters, which may include values of components in matching networks or bias voltages in the power amplifier or the power amplifier driver, so as to reduce the deviation and thereby improve the impedance matching. The load current of the power amplifier may alternatively be sensed by measuring the duty cycle of its switching mode power supply. A transmitter having a power amplifier and one or more tunable circuit elements incorporates an error detector that senses the amplitude or phase of a load current and a controller that adjusts one or more tunable parameters to reduce impedance mismatch.

Abstract: A method of increasing linearity of an RF signal receive path includes measuring a signal amplified by the receive path. The receive path has a local oscillator operating at an LO frequency and a ground. An error signal is determined from the amplified signal, the error signal being representative of the nonlinearity. An anti-spur tone is injected into the ground. The anti-spur tone has a frequency about equal to the LO frequency and an amplitude and phase that are determined to increase the linearity of the receive path.

Abstract: The present invention provides an RF transmission leakage mitigator for use with a full-duplex, wireless transceiver. In one embodiment, the RF transmission leakage mitigator includes an inversion generator configured to provide an RF transmission inversion signal of an interfering transceiver RF transmission to a receiving portion of the transceiver thereby creating a residual leakage signal. Additionally, the RF transmission leakage mitigator also includes a residual processor coupled to the inversion generator and configured to adjust the RF transmission inversion signal of the interfering transceiver RF transmission based on reducing the residual leakage signal to a specified level.

Abstract: Methods and apparatus to perform radio frequency (RF) analog-to-digital conversion are described. According to one example, a receiver includes an amplifier to amplify received analog RF signals and a mixer-free circuit for converting the received analog RF signals to digital signals.

Abstract: Methods and apparatus to implement receiver linearity enhancement are described. One example method includes controlling receiver gain by determining a level of a received signal that is to be provided to a radio frequency component; determining if the level of the received signal would cause the radio frequency components internally generated noise to increase; and when the level of the received signal would cause the radio frequency components internally generated noise to increase, reducing the level of the received signal prior to providing the received signal to the radio frequency component.

Abstract: A mixer 1100 with a plurality of signal paths typically requires separate clock generating hardware for each signal path. However, the redundancy of having multiple clock generating hardware significantly increases power consumption and integrated circuit area when the mixer 1100 is integrated into silicon. A method and apparatus 1125 containing a circuit for generating a set of clock signals that can be shared by the different signal paths is presented. Advantage is taken of the significant capacitance difference between different sampling capacitors in the mixer and the superposition property.

Abstract: System and method for elimination of close-in interferers through feedback. A preferred embodiment comprises an interferer predictor (for example, interferer predictor 840) coupled to a digital output of a direct RF radio receiver (for example, radio receiver 800). The interferer predictor predicts the presence of interferers and feeds the information back to a sampling unit (for example, sampling unit 805) through a feedback circuit (for example, feedback unit 845) through the use of charge sharing. The interferers are then eliminated in the sampling unit. Additionally, the number and placement of zeroes in a filter in the sampling unit is increased and changed through the implementation of arbitrary-coefficient finite impulse response filters.

Abstract: The present invention provides a local oscillator (LO) leakage controller for use with a receiver. In one embodiment, the LO leakage controller includes a comparison unit configured to process an LO leakage error signal from the receiver to provide a leakage cancellation signal. Additionally, the LO leakage controller also includes a leakage counterbalance unit coupled to the comparison unit and configured to adapt the leakage cancellation signal to the receiver to counterbalance LO leakage in the receiver.