A spacecraft includes a payload subsystem including a plurality of transmit antenna feeds, a digital channelizer, and a power amplification arrangement including a plurality of power amplifiers. The power amplification arrangement has at least one input communicatively coupled with an output of the digital channelizer and at least one output communicatively coupled with at least one of the plurality of transmit antenna feeds. A processor is configured to control the digital channelizer, and to adjust a saturated output power of at least one power amplifier of the plurality of power amplifiers in the power amplification arrangement.

Power amplifier having selective signal paths. In some embodiments, a power amplifier circuit can include a plurality of signal paths sharing a common amplification stage configured to partially amplify a signal. Each signal path can further include a dedicated amplification stage coupled to the common amplification stage and configured to be capable of further amplifying the partially amplified signal. The power amplifier circuit can further include a bias selector having a switch configured to provide a bias signal to a selected dedicated amplification stage among the plurality of signal paths to thereby allow the selected dedicated amplification stage to further amplify the partially amplified signal.

Methods, apparatus, systems, and articles of manufacture are disclosed to generate a modulation protocol to output audio. An example apparatus includes a modulation circuit including a first input, a second input, a first output, and a second output; a first gate coupled to the first output of the modulation circuit; a second gate coupled to the second output of the modulation circuit; a first multiplexer including a first input coupled to the first output of the modulation circuit, a second input coupled to the output of the second gate, and an output coupled to a first switch; and a second multiplexer including a first input coupled to the second output of the modulation circuit, a second input coupled to the output of the first gate, and an output coupled to a second switch.

A front end circuit includes a bypass circuit comprising a first bypass switch and a second bypass switch configured to bypass a signal to a first terminal according to switching operations of the first bypass switch and the second bypass switch; and an amplifier connected in parallel to the bypass circuit and configured to amplify the signal.

A method and network equipment for controlling power amplification are disclosed. The method for controlling power amplification includes outputting a voltage signal according to the state of network equipment. When the network equipment is in an idle state, at least one power amplifier transistor is switched off according to a voltage signal.

Disclosed herein are amplification systems that are dynamically biased based on a signal indicative of differential envelope of an input radio-frequency (RF) signal being amplified. The amplification systems include a cascode amplifier configured to amplify the RF signal to generate an output RF signal when one of the transistors of the cascode amplifier is biased by a combination of the input RF signal and a biasing signal while the other transistor of the cascode amplifier is biased by a processed differential envelope signal. The cascode amplifier also receives a combination of a processed differential envelope signal and a supply voltage to generate the output RF signal. The biasing signal can improve or enhance the linearity of amplification systems.

A low-noise amplifier in a receiver supporting a beam forming function may selectively change a phase shift for beam steering. The low-noise amplifier may include first and second transistors and a variable capacitance circuit connected to a gate of the second transistor. The variable capacitance circuit may selectively change capacitance thereof based on a capacitance control signal applied thereto according to beam-forming information, where the changed capacitance correspondingly causes a phase change in an output signal of the low-noise amplifier. A similar scheme may be employed for amplifiers in transmit signal paths to steer a transmit beam.

An amplifier having a Radio Frequency (RF) power level detector circuit for producing a control signal in accordance with a power level of an RF input signal. The control signal indicates whether the power level of the input signal is within a predetermined range of power levels greater than zero. A bias circuit is fed by the control signal, for producing a fixed bias voltage at a gate electrode of a field effect transistor (FET) to establish a predetermined quiescent current for the FET when the control signal indicates the power level of the RF input signal is within the predetermined range of power levels and to reduce the bias voltage to reduce the predetermined quiescent current when the control signal indicates the power level of the RF input signal is below the predetermined range of power levels.

An amplifier having a Radio Frequency (RF) power level detector circuit for producing a control signal in accordance with a power level of an RF input signal. The control signal indicates whether the power level of the input signal is within a predetermined range of power levels greater than zero. A bias circuit is fed by the control signal, for producing a fixed bias voltage at a gate electrode of a field effect transistor (FET) to establish a predetermined quiescent current for the FET when the control signal indicates the power level of the RF input signal is within the predetermined range of power levels and to reduce the bias voltage to reduce the predetermined quiescent current when the control signal indicates the power level of the RF input signal is below the predetermined range of power levels.

An apparatus for turning off a cascode amplifier having a common-base transistor and a common-emitter transistor is disclosed that includes the cascode amplifier, a feedback circuit, and a bias circuit. The feedback circuit is configured to receive a collector-voltage from the collector of the common-emitter transistor when the common-emitter transistor is switched to a first OFF state and produce a first feedback signal. The collector-voltage is equal to a emitter voltage of the common-base transistor and the collector-voltage increases in response to switching the common-emitter transistor to the first OFF state. The bias circuit is configured to receive the first feedback signal and produce a bias-voltage. A first base-voltage is produced from the bias-voltage. The cascode amplifier is configured to receive the first base-voltage and a second base-voltage. The common-base transistor is configured to switch to a second OFF state in response to receiving the second base-voltage.