Abstract: An apparatus for providing envelope tracking (ET), comprising: a power amplifier (PA) load variation pre-distortion, and an open loop ET modulator operatively coupled to the PA load variation pre-distortion, wherein the PA load variation pre-distortion is configured to determine a load variation at a PA supply voltage path based on an input signal received by a PA, and generate a pre-distortion compensation signal using the load variation, and wherein the open loop ET modulator is configured to generate a PA supply voltage on the PA supply voltage path using the pre-distortion compensation signal.

Abstract: Aspects of the disclosure can provide a circuit to be used in a device. The circuit includes a first receiver circuit, a second receiver circuit and a processing circuit. The first receiver circuit is configured to receive a first signal from an antenna that captures a combination of a target signal transmitted from another device to the device and an output signal driven by a transmitter in the device. The second receiver circuit is configured to receive a second signal generated based on to the output signal. The processing circuit is configured to cancel from the first signal noise due to the output signal based on the second signal.

Abstract: An apparatus comprises an amplifier having an input coupled to a radio frequency signal through a digital-to-analog circuit, an adaptive power supply having an output coupled to a bias voltage of the amplifier, wherein the output of the adaptive power supply is configured to have a shape similar to an envelope of the radio frequency signal and a feedback circuit comprising a sensing circuit and a mapping circuit, wherein the sensing circuit is configured to sense a current flowing from the adaptive power supply to the amplifier and sense the bias voltage of the amplifier, and wherein the mapping circuit is configured to sense the bias voltage of the amplifier, and wherein the mapping circuit is configured to generate a control signal for dynamically adjusting parameters of a low pass filter so as to stabilize the adaptive power supply.

Abstract: An apparatus for providing envelope tracking (ET), comprising: a power amplifier (PA) load variation pre-distortion, and an open loop ET modulator operatively coupled to the PA load variation pre-distortion, wherein the PA load variation pre-distortion is configured to determine a load variation at a PA supply voltage path based on an input signal received by a PA, and generate a pre-distortion compensation signal using the load variation, and wherein the open loop ET modulator is configured to generate a PA supply voltage on the PA supply voltage path using the pre-distortion compensation signal.

Abstract: A method for implementing envelope tracking (ET), the method comprising switching from a receiver (Rx) radio frequency (RF) path to a supply sensing path during factory calibration, sensing the power amplifier (PA)'s supply voltage via the supply sensing path, comparing the PA's supply voltage to a corresponding reference supply voltage, determining the difference between the PA's supply voltage and the corresponding reference supply voltage, and updating one or more parameters used to perform a PA load pre-distortion during factory calibration, wherein the PA load pre-distortion is used to match the PA's supply voltage to the corresponding reference supply voltage.

Abstract: Local oscillator (LO) in-phase/quadrature (IQ) imbalance correction data are generated for one or both of the transmitter and receiver of a radio-frequency (RF) communication device. An RF transmitter output signal is generated by the transmitter from a known test signal and transmitted to the receiver, where a baseband receiver signal is produced. A signal characteristic of the receiver baseband signal is measured in the presence of phase shifts introduced in the transmitter output signal. Joint LO IQ imbalance figures of merit are computed from the signal characteristic measurements, each characterizing signal processing artifacts in the receiver baseband signal caused by joint signal processing in the transmitter and the receiver under influence of transmitter LO IQ imbalance and receiver LO IQ imbalance.

Abstract: To generate amplitude modulation to phase modulation (AMPM) predistortion data that compensates for phase distortion in a power amplifier of a communication device, a test signal is amplified via the power amplifier. The amplified test signal is combined, by wave superposition, with a reference oscillator signal into a resultant signal. The resultant signal is an outcome of interference between the amplified test signal and the reference oscillator signal. The resultant signal power is measured using envelope information and, from the measurement, a predistortion phase shift is determined that when applied to the test signal maximizes the interference between the amplified test signal and the reference oscillator signal. AMPM predistortion data is generated to correspond with the predistortion phase shift.

Abstract: Aspects of the disclosure can provide a circuit to be used in a device. The circuit includes a first receiver circuit, a second receiver circuit and a processing circuit. The first receiver circuit is configured to receive a first signal from an antenna that captures a combination of a target signal transmitted from another device to the device and an output signal driven by a transmitter in the device. The second receiver circuit is configured to receive a second signal generated based on to the output signal. The processing circuit is configured to cancel from the first signal noise due to the output signal based on the second signal.

Abstract: A direct conversion transmitter has a mixer stage to up-convert an input signal to the frequency of a local oscillator (LO). A DC offset circuit is coupled to an input signal port to apply a set of DC offset signal values. A processor determines a set of optimal DC offset signal values by no more than three differential spectral measurements made at the transmitter output port with a test signal applied at the input port. Optimal DC offset signal values are those that, when applied to the input signal at the input port of the transmitter, minimize an LO leakage component of the transmit signal at the output signal port of the transmitter. The optimal DC offset values are stored in memory and retrieved and applied to information bearing signals provided as the input signal once those optimal DC offset values have been determined.

Abstract: Local oscillator (LO) in-phase/quadrature (IQ) imbalance correction data are generated for one or both of the transmitter and receiver of a radio-frequency (RF) communication device. An RF transmitter output signal is generated by the transmitter from a known test signal and transmitted to the receiver, where a baseband receiver signal is produced. A signal characteristic of the receiver baseband signal is measured in the presence of phase shifts introduced in the transmitter output signal. Joint LO IQ imbalance figures of merit are computed from the signal characteristic measurements, each characterizing signal processing artifacts in the receiver baseband signal caused by joint signal processing in the transmitter and the receiver under influence of transmitter LO IQ imbalance and receiver LO IQ imbalance.

Abstract: A direct conversion transmitter has a mixer stage to up-convert an input signal to the frequency of a local oscillator (LO). A DC offset circuit is coupled to an input signal port to apply a set of DC offset signal values. A processor determines a set of optimal DC offset signal values by no more than three differential spectral measurements made at the transmitter output port with a test signal applied at the input port. Optimal DC offset signal values are those that, when applied to the input signal at the input port of the transmitter, minimize an LO leakage component of the transmit signal at the output signal port of the transmitter. The optimal DC offset values are stored in memory and retrieved and applied to information bearing signals provided as the input signal once those optimal DC offset values have been determined.

Abstract: Phase and gain of a transmit signal are measured at a transmitter by determining a first time delay having a first resolution at a measurement receiver between a reference signal from which the transmit signal is generated and a measured signal derived from the transmit signal by comparing amplitudes of the reference signal and the measured signal. A second time delay having a second resolution finer than the first resolution is determined at the measurement receiver between the reference signal and the measured signal based on the first time delay. The reference signal and the measured signal are time aligned at the measurement receiver based on the second time delay and the phase and gain of the transmit signal are estimated after the reference signal and the measured signal are time aligned.

Abstract: The present invention is a method for calibrating a phase distortion compensated polar modulated RF transmitter, which uses amplitude pre-distortion to compensate for phase distortion, called AMPM compensation. Some embodiments of the present invention may include a method for calibrating polar modulated RF transmitters that use amplitude pre-distortion to compensate for amplitude non-linearities, called AMAM compensation. The AMPM and AMAM compensations may enable the polar modulated RF transmitter to conform to RF output power tolerances, meet EVM specifications, and meet ORFS requirements. The pre-distortion calibration methods may be used to determine calibration constants by measuring phase distortion and amplitude non-linearities. During normal operation, the calibration constants may be used to provide the AMPM and AMAM compensations.

Abstract: Phase and gain of a transmit signal are measured at a transmitter by determining a first time delay having a first resolution at a measurement receiver between a reference signal from which the transmit signal is generated and a measured signal derived from the transmit signal by comparing amplitudes of the reference signal and the measured signal. A second time delay having a second resolution finer than the first resolution is determined at the measurement receiver between the reference signal and the measured signal based on the first time delay. The reference signal and the measured signal are time aligned at the measurement receiver based on the second time delay and the phase and gain of the transmit signal are estimated after the reference signal and the measured signal are time aligned.

Abstract: A system and method are provided for calibrating Amplitude Modulation to Phase Modulation (AM/PM) pre-distortion in a transmitter operating according to a polar modulation scheme. In general, phase modulation is disabled during transmission of an actual polar modulation signal. As a result, the transmitter provides a radio frequency (RF) output signal having an amplitude modulation component and ideally a constant phase. However, the AM/PM distortion of the transmitter creates a phase modulation component in the RF output signal. The phase component of the RF output signal, which is the AM/PM distortion of the transmitter, is measured by test equipment. The AM/PM pre-distortion applied by the transmitter is then calibrated based on the measured AM/PM distortion such that the AM/PM distortion of the transmitter is substantially reduced.