A method of characterizing an envelope tracking amplification stage, the method comprising: generating an input test waveform which is representative of an input waveform under normal operating conditions of the amplification stage; applying a respective one of a plurality of different shaping functions, each comprising a non-linear transfer function, to the input signal envelope in each of a plurality of test periods during the period in which the input test waveform is applied as the input signal to generate the input to the envelope tracking modulated supply voltage; measuring parameters of the amplification stage during the period in which the input test waveform is applied in order to allow determination of the gain, phase and efficiency characteristics of the amplifier; and for each of the gain, phase and efficiency characteristics, generating a three dimensional plot of the characteristic with respect to input power and supply voltage applied to the amplifier.

The present invention provides an RF power amplifier architecture which with dynamic digital control of the amplification by incorporating digitized RF input and output signal envelope data and environmental temperature sensor(s) readings into an arbitrary control algorithm implemented on a digital processor. Via the combination of digitally controlled DC/DC converter and a D/A converter, the quiescent bias of the power FET of the RF output stage can become a realization of virtually any function of the feedback and input data.

Techniques for controlling the output of a power amplifier are disclosed. In one embodiment, the techniques may be realized as a system that includes a power amplifier and a controller coupled to the power amplifier to form a feedback loop. The power amplifier is enabled or disabled in response to a blanking signal. The controller includes an accumulator that stores an accumulated error of the feedback loop. The controller suspends operation of the accumulator when (1) a level of the input signal is below a first threshold for an amount of time that exceeds a second threshold, (2) the blanking signal indicates that the power amplifier is disabled, or (3) both. The controller resumes operation of the accumulator when (1) the level of the input signal is above the first threshold and (2) the blanking signal indicates that the power amplifier is enabled.

A system includes a quantum processor includes a plurality of qubits. For each qubit, there is a circulator operative to receive a control signal and an output signal from the qubit. An isolator is coupled to an output of the circulator. A quantum-limited amplifier is coupled to an output of the isolator and configured to provide an output of the qubit. A multiplexor (MUX) is configured to frequency multiplex the outputs of at least two of the plurality of qubits as a single output of the quantum processor.

A system includes a quantum processor includes a plurality of qubits. For each qubit, there is a circulator operative to receive a control signal and an output signal from the qubit. An isolator is coupled to an output of the circulator. A quantum-limited amplifier is coupled to an output of the isolator and configured to provide an output of the qubit. A multiplexor (MUX) is configured to frequency multiplex the outputs of at least two of the plurality of qubits as a single output of the quantum processor.

Techniques for controlling the output of a power amplifier are disclosed. In one embodiment, the techniques may be realized as a system that includes a power amplifier and a controller coupled to the power amplifier to form a feedback loop. The power amplifier is enabled or disabled in response to a blanking signal. The controller includes an accumulator that stores an accumulated error of the feedback loop. The controller suspends operation of the accumulator when (1) a level of the input signal is below a first threshold for an amount of time that exceeds a second threshold, (2) the blanking signal indicates that the power amplifier is disabled, or (3) both. The controller resumes operation of the accumulator when (1) the level of the input signal is above the first threshold and (2) the blanking signal indicates that the power amplifier is enabled.

Disclosed are an electronic impedance tuning apparatus for measuring a load-pull of a mobile amplifier and an electronic impedance tuning method therefor. An electronic impedance tuning apparatus according to one embodiment of the present invention comprises: a coupler for transferring, to transmission lines respectively connected to a through port and a coupled port, an input voltage inputted to an input port; a magnitude part for controlling a change in the magnitude of the impedance through a change in length difference of the transmission lines; and a phase part for controlling a change in the phase of the impedance through an equal length change of the transmission lines.

Techniques for controlling the output of a power amplifier are disclosed. In one embodiment, the techniques may be realized as a system that includes a power amplifier and a controller coupled to the power amplifier to form a feedback loop. The power amplifier is enabled or disabled in response to a blanking signal. The controller includes an accumulator that stores an accumulated error of the feedback loop. The controller suspends operation of the accumulator when (1) a level of the input signal is below a first threshold for an amount of time that exceeds a second threshold, (2) the blanking signal indicates that the power amplifier is disabled, or (3) both. The controller resumes operation of the accumulator when (1) the level of the input signal is above the first threshold and (2) the blanking signal indicates that the power amplifier is enabled.

Disclosed are an electronic impedance tuning apparatus for measuring a load-pull of a mobile amplifier and an electronic impedance tuning method therefor. An electronic impedance tuning apparatus according to one embodiment of the present invention comprises: a coupler for transferring, to transmission lines respectively connected to a through port and a coupled port, an input voltage inputted to an input port; a magnitude part for controlling a change in the magnitude of the impedance through a change in length difference of the transmission lines; and a phase part for controlling a change in the phase of the impedance through an equal length change of the transmission lines.

An amplifier circuit (200) for compensating an output signal provided at an output (212) of a circuit (210) is disclosed. The amplifier circuit (200) comprises an output transmission line (230) connected between the output (212) of the circuit (210) and an output port (240) and an amplifier (220). The amplifier (220) comprises multiple sub-amplifiers (221, 222, 223, 224), inputs of the multiple sub-amplifiers (221, 222, 223, 224) are coupled to an input transmission line (250) for receiving an error signal; and outputs of the multiple sub-amplifiers (221, 222, 223, 224) are coupled at respective places along the output transmission line (230) to inject a compensation signal to the output port (240). The error signal is derived from a reference input signal and the output signal of the circuit (210), and is amplified in the amplifier (220) into the compensation signal.