A communication circuit may include a first pair of digital-to-analog converters (DACs) coupled to an input of a first mixer and configured to generate first baseband signals. The communication circuit may further include a second pair of DACs coupled to an input of a second mixer and configured to generate second baseband signals. The second baseband signals may be shifted in phase relative to the first baseband signals.

A RF control circuit is provided and includes a controller, a divider, and a RF sensor. The controller selects a RF, which is a frequency of a reference LO signal. The divider receives a first RF signal detected in a substrate processing chamber and outputs a second RF signal. The first RF signal is generated by a RF generator and supplied to the substrate processing chamber. The RF sensor includes a lock-in amplifier, which includes: a RF path that receives the second RF signal; a LO path that receives the reference LO signal; a first mixer that generates an IF signal based on the second RF signal and the reference LO signal; and a filter that filters the IF signal. The controller generates a control signal based on the filtered IF signal and transmits the control signal to the RF generator to adjust the first RF signal.

A monolithically integrated device includes a substrate, a first set of Group III nitride epitaxial layers grown for a first HFET on a first region of the substrate, and a second set of Group III nitride epitaxial layers for a second HFET grown on a second region of the substrate.

Embodiments of the disclosure relate to optimizing power efficiency of a power amplifier circuit to reduce power consumption in a remote unit in a wireless distribution system (WDS). A power amplifier circuit is provided in the remote unit to amplify a received input signal associated with a signal channel(s) to generate an output signal at an aggregated peak power. In this regard, a control circuit is configured to analyze at least one physical property related to the signal channel(s) to determine a maximum output power of the power amplifier circuit. Accordingly, the control circuit configures the power amplifier circuit according to the determined maximum output power. By configuring the maximum output power based on the signal channel(s) in the input signal, it may be possible to optimize the power efficiency of the power amplifier circuit, thus helping to reduce the power consumption of the remote unit.

A Doherty amplifier circuit having a tunable impedance and phase (TIP) circuit to provide an adjustable alpha factor, which allows for a selection of power added efficiency (PAE) curves that are useful for applications having different modulations or to meet other criteria. Embodiments include a Doherty amplifier having a TIP circuit that provides for tunability of the impedance Z.sub.INV (resulting in an adjustable alpha factor) while maintaining the phase of the output of the carrier amplifier at 90 (for a selected polarity)a low phase variation. Embodiments of the TIP circuit include one or more series-connected TIP cells comprising at least one TIP circuit combined with a tunable phase adjustment circuit. In operation, when the impedance of a TIP cell is adjusted, adjustments within the cell are also made to provide a phase shift correction back towards 90 (at the selected polarity).

A semiconductor circuit including a clocked comparator and an offset application circuit. The clocked comparator is configured to receive a first input signal and a second input signal from a host and compare the first input signal and the second input signal. The offset application circuit is configured to apply an offset to the first input signal. The clocked comparator is configured to be driven based on a reference clock provided from the host.

A transformer has a first winding, a second winding, a third winding, a fourth winding and a fifth winding. The fifth winding has a first part and a second part serially connected to the first part. The first part is magnetically coupled to the second winding and magnetically isolated from the first winding, and the second part is magnetically coupled to the fourth winding and magnetically isolated from the third winding. The second winding is positioned between the first winding and the first part, the first winding is positioned adjacent to the second winding, and the second winding is positioned adjacent to the first part. The fourth winding is positioned between the third winding and the second part, the third winding is positioned adjacent to the fourth winding, and the fourth winding is positioned adjacent to the second part.

An amplifier amplifies an input signal. A splitter branches an output signal of the amplifier into a first signal path and a second signal path and performs impedance conversion of the first and second signal paths. A first output terminal outputs the output signal of the amplifier or a signal obtained by branching the output signal of the amplifier into the first signal path by the splitter. A second output terminal outputs the output signal of the amplifier or a signal obtained by branching the output signal of the amplifier into the second signal path by the splitter. An output controller switches whether the output signal of the amplifier is output from the first output terminal, is output from the second output terminal, or is branched by the splitter to be output from both the first and second output terminals.

An apparatus for power amplifier control is provided, applied to a multi-stage power amplifier. The apparatus controls an input voltage of an amplification triode in the first amplification stage, by using a detected current change at a base of an amplification triode in the last amplification stage, achieving control of output power and a maximum output current of the multi-stage power amplifier, greatly reducing an influence of current detection on maximum output power and maximum output efficiency of the power amplifier.

A radio frequency (RF) power combining amplifier circuit has a circuit input and a circuit output. A first amplifier is connected to the circuit input and to a first bias input. A first output matching network is connected to an output of the first amplifier and to the circuit output. A second amplifier is connected to the circuit input and to a second bias input. A second output matching network is connected to an output of the second amplifier, and to the circuit output. A voltage level of an input signal applied to the circuit input, together with the respective first bias input and the second bias input, selectively activates the first amplifier and the second amplifier.