An embodiment electronic device comprises at least two antennas for transmitting signals, and at least one transmission path, the transmission path including a first coupling stage including a power divider, variable-gain power amplifiers, and a second coupling stage including a power combiner. Each coupling stage includes two inputs and two outputs, the two inputs of the first coupling stage being configured to receive a power input signal. Each output of the first coupling stage is connected to a different input of the second coupling stage via the variable-gain power amplifiers, and each output of the second coupling stage is connected to a different antenna. A controller is configured to control the gains of the variable-gain power amplifiers according to the characteristics of the power input signal, the signals transmitted by the antennas, and the coupling stages.

A circuit for generating a radio frequency signal is provided. The circuit includes an amplifier configured to generate a radio frequency signal based on a baseband signal. Further, the circuit includes a power supply configured to generate a variable supply voltage based on a control signal indicating a desired supply voltage, and to supply the variable supply voltage to the amplifier. The circuit further includes an envelope tracking circuit configured to generate the control signal based on a bandwidth of the baseband signal, and to supply the control signal to the power supply.

Envelope tracking power amplifiers with advanced gain shaping are provided. In certain implementations, a power amplifier system includes a power amplifier that amplifies a radio frequency (RF) signal and an envelope tracker that controls a voltage level of a supply voltage of the power amplifier based on an envelope of the RF signal. The power amplifier system further includes a gain shaping circuit that generates a gain shaping current that changes with the voltage level of the supply voltage from the envelope tracker. For example, the gain shaping circuit can include an analog look-up table (LUT) mapping a particular voltage level of the supply voltage to a particular current level of gain shaping current. Additionally, the gain shaping circuit biases the power amplifier based on the gain shaping current.

In one example in accordance with the present disclosure, an antenna system is described. The antenna system includes an array of antennas. Each antenna emits electromagnetic waves and is presented with a load that is different from other antennas in the array. The antenna system also includes a control system. The control system includes a single transmitter to sequentially drive antenna sets, a switching device to select, for each activation period in an activation sequence, an antenna set to be driven, and a controller. The controller determines an actual power output of each antenna and generates an adjusted control signal for the single transmitter such that the output of each antenna is controlled to match a target power for that antenna, regardless of a load for the antenna.

A radio frequency power amplifier circuit includes a controllable attenuation circuit, an input matching circuit, a drive amplification circuit, an inter-stage matching circuit, a power amplification circuit and an output matching circuit connected in sequence, and respectively configured to switch between a negative gain mode and a non-negative gain mode of the radio frequency power amplifier circuit based on a mode control signal, match the impedance between the controllable attenuation circuit and the drive amplification circuit, amplify a signal, configured to match the impedance between the drive amplification circuit and the power amplification circuit, amplify a signal, and match the impedance between the radio frequency power amplifier circuit and a post-stage circuit. A feedback circuit is connected across the drive amplification circuit, and is configured to adjust a gain.

A TX-TX pre-compensation system that estimates unwanted coupling in a victim transmit chain caused by an aggressor transmit chain and injects a pre-compensation signal to cancel out the estimated coupling. In some embodiments, a signal measurement module estimates the amplitude, phase, and envelope delay of the coupling and an isolation pre-compensation module generates the pre-compensation signal based on the estimated amplitude, the estimated phase, the estimated envelope delay, and the difference between the carrier frequencies of the transmit chains. Since the phase of the coupling may be affected by the carrier frequency of the transmit chains, in some embodiments the phase of the pre-compensation signal is adjusted in response to a change in carrier frequency. Since the amplitude of the coupling may be affected by attenuator gain settings, in some embodiments the amplitude of the pre-compensation signal may be adjusted in response to a change in attenuator gain setting.

Techniques maintaining receiver reliability, including determining a present attenuation level for an attenuator, wherein the attenuation level is set by a gain controller, determining a relative reliability threshold based on the present attenuation level, receiving a radio frequency (RF) signal, determining a voltage level of the received RF signal, comparing the voltage level of the received RF signal to the relative reliability threshold to determine that a reliability condition exists, and overriding, in response to the determination that the reliability condition exists, the present attenuation level set by the gain controller with an override attenuation level based on the present attenuation level.

The present invention discloses a transmission circuit having output power compensation mechanism. A base-band circuit receives and processes a digital input signal to perform conversion and amplification according to at least one gain parameter to generate an analog output signal. A frequency up-converting circuit performs frequency up-conversion on the analog output signal to generate an RF signal. A RF amplification circuit amplifies the RF signal to generate an output RF signal to an antenna. A temperature monitoring circuit monitors temperature of the RF amplification circuit to generate an instant temperature value thereof. A calibration circuit increases at least a part of the gain parameter when the instant temperature value makes a power of the RF amplification circuit decrease and decreases at least a part of the gain parameter when the instant temperature value makes the power increase.

A gain attenuation circuit that attenuates an input RF signal and transmits the attenuated RF signal to a power transistor is provided. The gain attenuation circuit includes a first diode connected between a first node positioned between a port to which the input RF signal is input and a control terminal of the power transistor, and a ground; a first transistor and a second transistor stacked between a first power source and the ground, and each including a diode-connection structure; and a third transistor configured to receive an operating voltage set by the first transistor and the second transistor through a control terminal, and operate the first diode based on the received operating voltage.

An automatic gain control system for a receiver, including: an automatic gain control loop (40) adapted to be coupled to both a first transimpedance amplifier (12) coupled to a first analog-to-digital converter (14) forming a first tributary and a second transimpedance amplifier (12) coupled to a second analog-to-digital converter (14) forming a second tributary; and an offset gain control voltage to gain balance a transimpedance amplifier gain of the first tributary and a transimpedance amplifier gain of the second tributary. The automatic gain control loop can be analog. Also, the automatic gain control loop can be implemented in hardware or firmware.