Abstract: A transmission module is provided that includes a transmitter, a loopback receiver, and a QEC controller. The QEC controller identifies quadrature imbalance in the transmitter based at least one a comparison of the data signals at the output of the loopback receiver with data signals at the input of the transmitter. Based on the comparison, the QEC controller can adjust one or more characteristics of the transmitter to correct quadrature errors in the transmitter.

Abstract: Apparatus and methods for phase synchronization of phase-locked loops (PLLs) are provided. In certain configurations, an RF communication system includes a PLL that generates one or more output clock signals and a phase synchronization circuit that synchronizes a phase of the PLL. The phase synchronization circuit includes a sampling circuit that generates samples by sampling the one or more output clock signals based on timing of a reference clock signal. Additionally, the phase synchronization circuit includes a phase difference calculation circuit that generates a phase difference signal based on the samples and a tracking digital phase signal representing the phase of the PLL. The phase synchronization circuit further includes a phase adjustment control circuit that provides a phase adjustment to the PLL based on the phase difference signal so as to synchronize the PLL.

Abstract: Apparatus and methods for phase synchronization of phase-locked loops (PLLs) are provided. In certain configurations, an RF communication system includes a PLL that generates one or more output clock signals and a phase synchronization circuit that synchronizes a phase of the PLL. The phase synchronization circuit includes a sampling circuit that generates samples by sampling the one or more output clock signals based on timing of a reference clock signal. Additionally, the phase synchronization circuit includes a phase difference calculation circuit that generates a phase difference signal based on the samples and a tracking digital phase signal representing the phase of the PLL. The phase synchronization circuit further includes a phase adjustment control circuit that provides a phase adjustment to the PLL based on the phase difference signal so as to synchronize the PLL.

Abstract: Apparatus and methods for phase synchronization of phase-locked loops (PLLs) are provided. In certain configurations, an RF communication system includes a PLL that generates one or more output clock signals and a phase synchronization circuit that synchronizes a phase of the PLL. The phase synchronization circuit includes a sampling circuit that generates samples by sampling the one or more output clock signals based on timing of a reference clock signal. Additionally, the phase synchronization circuit includes a phase difference calculation circuit that generates a phase difference signal based on the samples and a tracking digital phase signal representing the phase of the PLL. The phase synchronization circuit further includes a phase adjustment control circuit that provides a phase adjustment to the PLL based on the phase difference signal so as to synchronize the PLL.

Abstract: Apparatus and methods for phase synchronization of phase-locked loops (PLLs) are provided. In certain configurations, an RF communication system includes a PLL that generates one or more output clock signals and a phase synchronization circuit that synchronizes a phase of the PLL. The phase synchronization circuit includes a sampling circuit that generates samples by sampling the one or more output clock signals based on timing of a reference clock signal. Additionally, the phase synchronization circuit includes a phase difference calculation circuit that generates a phase difference signal based on the samples and a tracking digital phase signal representing the phase of the PLL. The phase synchronization circuit further includes a phase adjustment control circuit that provides a phase adjustment to the PLL based on the phase difference signal so as to synchronize the PLL.

Abstract: A method and apparatus for estimating and compensating TX LO leakage using circuitry on a loopback path connecting the transmitter and receiver are provided. The TX LO leakage may be estimated by measuring the DC signal on the receiver, measuring the phase difference between the received LO signal and the receiver LO signal, and filtering LO harmonics that may arise from the use of non-linear mixers. The DC signal on the receiver may be measured by opening and closing the loopback path, or changing the gain of the loopback path, or flipping the phase of looped back TX signal. The method may be used in an initialization or tracking calibration scheme.

Abstract: A transmission module is provided that includes a transmitter, a loopback receiver, and a QEC controller. In a first state, the QEC controller calibrates the loopback receiver to remove quadrature imbalance in the loopback receiver. In a second state, a communication pathway is provided between the transmitter and the loopback receiver, and the QEC controller identifies quadrature imbalance in the transmitter based at least one a comparison of the data signals at the output of the loopback receiver with data signals at the input of the transmitter. Based on the comparison, the QEC controller can adjust one or more characteristics of the transmitter to correct quadrature errors in the transmitter.

Abstract: A transmission module is provided that includes a transmitter, a loopback receiver, and a QEC controller. In a first state, the QEC controller calibrates the loopback receiver to remove quadrature imbalance in the loopback receiver. In a second state, a communication pathway is provided between the transmitter and the loopback receiver, and the QEC controller identifies quadrature imbalance in the transmitter based at least one a comparison of the data signals at the output of the loopback receiver with data signals at the input of the transmitter. Based on the comparison, the QEC controller can adjust one or more characteristics of the transmitter to correct quadrature errors in the transmitter.

Abstract: A transmission module is provided that includes a transmitter, a loopback receiver, and a QEC controller. The QEC controller identifies quadrature imbalance in the transmitter based at least one a comparison of the data signals at the output of the loopback receiver with data signals at the input of the transmitter. Based on the comparison, the QEC controller can adjust one or more characteristics of the transmitter to correct quadrature errors in the transmitter.

Abstract: A method and apparatus for estimating and compensating TX LO leakage using circuitry on a loopback path connecting the transmitter and receiver are provided. The TX LO leakage may be estimated by measuring the DC signal on the receiver, measuring the phase difference between the received LO signal and the receiver LO signal, and filtering LO harmonics that may arise from the use of non-linear mixers. The DC signal on the receiver may be measured by opening and closing the loopback path, or changing the gain of the loopback path, or flipping the phase of looped back TX signal. The method may be used in an initialization or tracking calibration scheme.

Abstract: A system and method for detecting both the forward and reverse power of a power amplifier are provided. The power amplifier is a quadrature power amplifier including an in-phase amplifier circuit and a quadrature-phase amplifier circuit. A radio frequency (RF) input signal is split and phase-shifted to provide an in-phase RF input to the in-phase amplifier circuitry and a quadrature-phase RF input to the quadrature-phase amplifier circuitry, where the quadrature-phase RF input is +90 degrees out-of-phase with the in-phase RF input. In one embodiment, a power detection system operates to downconvert quadrature output signals from the in-phase and quadrature-phase amplifier circuits based on quadrature local oscillator signals.