Abstract: An electronic device may include wireless circuitry. The wireless circuitry may include at least a digital predistortion circuit, an upconversion circuit, and a load-line modulated amplifier circuit. The digital predistortion circuit can be configured to receive a reference baseband signal from one or more processors and to selectively output a predistorted version of the reference baseband signal. The upconversion circuit can be configured to receive a signal from the digital predistortion circuit and to output a radio-frequency signal. The load-line modulated amplifier circuit can be configured to amplify the radio-frequency signal. The load-line modulated amplifier circuit can include an adjustable load component.

Abstract: This disclosure is directed to compensating for gain drift due to switching the output power of a transmitter of an electronic device. In some cellular network applications, the transmit power level of a transmitter may be frequently adjusted from a low power level to a high power level. If the power level is not switched to the desired power level within a given interval, the transmission signal may be distorted. To enable the transmitter to reach a desired output power within the interval, the voltage supply of a power amplifier may be raised during a low power symbol, which may produce an undesirable gain increase. To mitigate or eliminate the low power symbol gain increase, a gain compensation signal may be introduced into the transmitter. The compensation signal may be adjusted and refined by implementing a power control loop, the power control loop may include a signal generator.

Abstract: Wireless circuitry can include a processor that generates a baseband signal, an upconversion circuit that upconverts the baseband signals to a radio-frequency signal, and an amplifier that amplifies the radio-frequency signal. A tunable delay circuit can be used to selectively delay generation of the radio-frequency signal or to delay generation of another signal intended for the radio-frequency amplifier. The tunable delay circuit can be controlled using a closed-loop delay adaptation scheme. A feedback receiver that is coupled to an output of the amplifier can be used to generate a demodulated signal. A delay error measurement circuit can be used to receive the demodulated signal, to detect a peak by monitoring when an envelope of the demodulated signal crosses a threshold level, to compute an amount of asymmetry in the detected peak, and to output a signal that is used to control the tunable delay circuit.

Abstract: An electronic device may include wireless circuitry. The wireless circuitry may include at least a digital predistortion circuit, an upconversion circuit, and a load-line modulated amplifier circuit. The digital predistortion circuit can be configured to receive a reference baseband signal from one or more processors and to selectively output a predistorted version of the reference baseband signal. The upconversion circuit can be configured to receive a signal from the digital predistortion circuit and to output a radio-frequency signal. The load-line modulated amplifier circuit can be configured to amplify the radio-frequency signal. The load-line modulated amplifier circuit can include an adjustable load component.

Abstract: An electronic device may include wireless circuitry with a processor that generates baseband signals, an upconversion circuit that upconverts the baseband signals to radio-frequency signals, a power amplifier, an antenna, and a transmit filter with a frequency dependent filter response coupled between the output of the power amplifier and the antenna. To help mitigate the frequency dependent filter response, the wireless circuitry may further include predistortion circuitry having an amplifier load response estimator that implements a baseband model of the filter response, an amplifier non-linearity estimator that models the non-linear behavior of the amplifier, and a control signal generator for adjusting the power amplifier based on the output of the amplifier load response estimator and the amplifier non-linearity estimator.

Abstract: Wireless circuitry can include a processor that generates a baseband signal, an upconversion circuit that upconverts the baseband signals to a radio-frequency signal, and an amplifier that amplifies the radio-frequency signal. A tunable delay circuit can be used to selectively delay generation of the radio-frequency signal or to delay generation of another signal intended for the radio-frequency amplifier. The tunable delay circuit can be controlled using a closed-loop delay adaptation scheme. A feedback receiver that is coupled to an output of the amplifier can be used to generate a demodulated signal. A delay error measurement circuit can be used to receive the demodulated signal, to detect a peak by monitoring when an envelope of the demodulated signal crosses a threshold level, to compute an amount of asymmetry in the detected peak, and to output a signal that is used to control the tunable delay circuit.

Abstract: An apparatus for wireless communication is provided. The apparatus includes a processing circuit configured to receive data to be wirelessly transmitted within a predefined frequency range. Further, the processing circuit is configured to generate a first radio frequency transmit signal of a first frequency range based on the data, and to generate a second radio frequency transmit signal of a second frequency range based on the data. The first frequency range and the second frequency range are subranges of the predefined frequency range. The apparatus further includes a front-end circuit configured to supply the first radio frequency transmit signal to a first antenna, and to supply the second radio frequency transmit signal to a second antenna.

Abstract: This disclosure is directed to compensating for gain drift due to switching the output power of a transmitter of an electronic device. In some cellular network applications, the transmit power level of a transmitter may be frequently adjusted from a low power level to a high power level. If the power level is not switched to the desired power level within a given interval, the transmission signal may be distorted. To enable the transmitter to reach a desired output power within the interval, the voltage supply of a power amplifier may be raised during a low power symbol, which may produce an undesirable gain increase. To mitigate or eliminate the low power symbol gain increase, a gain compensation signal may be introduced into the transmitter. The compensation signal may be adjusted and refined by implementing a power control loop, the power control loop may include a power controller.

Abstract: Wireless circuitry may include a radio-frequency amplifier configured to receive a power supply voltage, a load modulation circuit configured to generate a load control signal, and supply voltage error compensation circuitry configured to generate an error signal that is applied to the load control signal to produce a compensated load control signal. The compensated load control signal can be used to tune an adjustable load component of the radio-frequency amplifier. The power supply voltage may exhibit a piecewise constant waveform. The supply voltage error compensation circuitry can include a reference signal generator configured to generate a reference signal and a filter configured to generate a target signal based on the reference signal. The error signal can be computed based on a difference between the target signal and a sensed or estimated version of the power supply voltage received at the amplifier.

Abstract: An electronic device may include wireless circuitry. The wireless circuitry may include a radio-frequency amplifier having a data input configured to receive a radio-frequency signal generated from a baseband signal, supply modulation blocks configured to output a power supply voltage, derived from the baseband signal, for powering the radio-frequency amplifier, and load modulation blocks configured to output a load control signal, derived from the baseband signal and a bandwidth reduced envelope signal output from the supply modulation circuitry, for tuning an adjustable load component of the radio-frequency amplifier. The supply modulation blocks can include a full envelope generator, a bandwidth reduction block for outputting the bandwidth reduced envelope signal, an envelope shaping block, and an envelope tracker. The load modulation blocks can include an inverse amplifier gain model and a load shaping block.

Abstract: A predistortion circuit for a wireless transmitter includes a signal input configured to receive a baseband signal. Further, the predistortion circuit includes a predistorter configured to generate a predistorted baseband signal using the baseband signal and a select of one of a first predistorter configuration and a second predistorter configuration.

Abstract: An electronic device may include wireless circuitry with a processor that generates baseband signals, an upconversion circuit that upconverts the baseband signals to radio-frequency signals, a power amplifier, an antenna, and a transmit filter with a frequency dependent filter response coupled between the output of the power amplifier and the antenna. To help mitigate the frequency dependent filter response, the wireless circuitry may further include predistortion circuitry having an amplifier load response estimator that implements a baseband model of the filter response, an amplifier non-linearity estimator that models the non-linear behavior of the amplifier, and a control signal generator for adjusting the power amplifier based on the output of the amplifier load response estimator and the amplifier non-linearity estimator.

Abstract: An electronic device may include wireless circuitry with a processor that generates baseband signals, an upconversion circuit that upconverts the baseband signals to radio-frequency signals, a power amplifier, an antenna, and a transmit filter with a frequency dependent filter response coupled between the output of the power amplifier and the antenna. To help mitigate the frequency dependent filter response, the wireless circuitry may further include predistortion circuitry having an amplifier load response estimator that implements a baseband model of the filter response, an amplifier non-linearity estimator that models the non-linear behavior of the amplifier, and a control signal generator for adjusting the power amplifier based on the output of the amplifier load response estimator and the amplifier non-linearity estimator.

Abstract: An electronic device may include wireless circuitry having an amplifier configured to receive a radio-frequency signal generated from a baseband signal, a first adjustable load component coupled to an output of the amplifier, a second adjustable load component coupled to the output of the amplifier, and a control signal generator configured to output one or more control signals for tuning the first and second adjustable load components based on an envelope of the baseband signal or the radio-frequency signal. The first adjustable load component can provide a first tuning range covering a first subrange of an instantaneous signal envelope of the baseband signal or the radio-frequency signal, whereas the second adjustable load can provide a second tuning range covering a second subrange of the instantaneous signal envelope of the baseband signal or the radio-frequency signal. The first and second tuning ranges are combined to provide an extended tuning range.

Abstract: This disclosure is directed to compensating for gain drift due to switching the output power of a transmitter of an electronic device. In some cellular network applications, the transmit power level of a transmitter may be frequently adjusted from a low power level to a high power level. If the power level is not switched to the desired power level within a given interval, the transmission signal may be distorted. To enable the transmitter to reach a desired output power within the interval, the voltage supply of a power amplifier may be raised during a low power symbol, which may produce an undesirable gain increase. To mitigate or eliminate the low power symbol gain increase, a gain compensation signal may be introduced into the transmitter. The compensation signal may be adjusted and refined by implementing a power control loop, the power control loop may include a power controller.

Abstract: This disclosure is directed to compensating for gain drift due to switching the output power of a transmitter of an electronic device. In some cellular network applications, the transmit power level of a transmitter may be frequently adjusted from a low power level to a high power level. If the power level is not switched to the desired power level within a given interval, the transmission signal may be distorted. To enable the transmitter to reach a desired output power within the interval, the voltage supply of a power amplifier may be raised during a low power symbol, which may produce an undesirable gain increase. To mitigate or eliminate the low power symbol gain increase, a gain compensation signal may be introduced into the transmitter. The compensation signal may be adjusted and refined by implementing a power control loop, the power control loop may include a signal generator.

Abstract: Wireless circuitry can include a processor that generates a baseband signal, an upconversion circuit that upconverts the baseband signals to a radio-frequency signal, and an amplifier that amplifies the radio-frequency signal. A tunable delay circuit can be used to selectively delay generation of the radio-frequency signal or to delay generation of another signal intended for the radio-frequency amplifier. The tunable delay circuit can be controlled using a closed-loop delay adaptation scheme. A feedback receiver that is coupled to an output of the amplifier can be used to generate a demodulated signal. A delay error measurement circuit can be used to receive the demodulated signal, to detect a peak by monitoring when an envelope of the demodulated signal crosses a threshold level, to compute an amount of asymmetry in the detected peak, and to output a signal that is used to control the tunable delay circuit.

Abstract: An electronic device may include radar circuitry. Control circuitry may calibrate the radar circuitry using a multi-tone calibration signal. A first mixer may upconvert the calibration signal for transmission by a transmit antenna. A de-chirp mixer may mix the calibration signal output by the first mixer with the calibration signal as received by a receive antenna or loopback path to produce a baseband multi-tone calibration signal. The baseband signal will be offset from DC by the frequency gap. This may prevent DC noise or other system effects from interfering with the calibration signal. The control circuitry may sweep the first mixer over the radio frequencies of operation of the radar circuitry to estimate the power droop and phase shift of the radar circuitry based on baseband calibration signal. Distortion circuitry may distort transmit signals used in spatial ranging operations to invert the estimated power droop and phase shift.

Abstract: An electronic device may include wireless circuitry. The wireless circuitry may include at least a digital predistortion circuit, an upconversion circuit, and a load-line modulated amplifier circuit. The digital predistortion circuit can be configured to receive a reference baseband signal from one or more processors and to selectively output a predistorted version of the reference baseband signal. The upconversion circuit can be configured to receive a signal from the digital predistortion circuit and to output a radio-frequency signal. The load-line modulated amplifier circuit can be configured to amplify the radio-frequency signal. The load-line modulated amplifier circuit can include an adjustable load component.

Abstract: An electronic device may include radar circuitry. Control circuitry may calibrate the radar circuitry using a multi-tone calibration signal. A first mixer may upconvert the calibration signal for transmission by a transmit antenna. A de-chirp mixer may mix the calibration signal output by the first mixer with the calibration signal as received by a receive antenna or loopback path to produce a baseband multi-tone calibration signal. The baseband signal will be offset from DC by the frequency gap. This may prevent DC noise or other system effects from interfering with the calibration signal. The control circuitry may sweep the first mixer over the radio frequencies of operation of the radar circuitry to estimate the power droop and phase shift of the radar circuitry based on baseband calibration signal. Distortion circuitry may distort transmit signals used in spatial ranging operations to invert the estimated power droop and phase shift.