The present disclosure relates to a 5.sup.th generation (5G) or pre-5G communication system for supporting higher data transmission rates than 4.sup.th generation (4G) communication systems such as long-term evolution (LTE). In a wireless communication system, an apparatus comprises: a first amplifier unit that has a common source structure, includes cross-coupled capacitors, and amplifies an input signal; and a second amplifier unit that has a common gate structure, is connected to the first amplifier unit, and amplifies the signal output from the first amplifier unit, wherein the second amplifier unit includes a first input unit, a second input unit, a third input unit, and a fourth input unit, and two input units among the first input unit, the second input unit, the third input unit, and the fourth input unit may be connected to the first amplifier unit.

A bidirectional RF circuit, preferably including a plurality of terminals, a switch, a transistor, a coupler, and a feedback network. The circuit can optionally include a drain matching network, an input matching network, and/or one or more tuning inputs. In some variations, the circuit can optionally include one or more impedance networks, such as an impedance network used in place of the feedback network; in some such variations, the circuit may not include a coupler, switch, and/or input matching network. A method for circuit operation, preferably including operating in an amplifier mode, operating in a rectifier mode, and/or transitioning between operation modes.

A sign switching circuitry is disclosed. In one aspect, the sign switching circuitry includes a first and second differential common-source amplifier having common differential input nodes and common differential output nodes configured such that a differential input signal applied at the common differential input nodes is amplified to a differential output signal at the common differential output nodes with a fixed gain by the first amplifier and by the fixed gain with opposite sign by the second amplifier. The sign switching circuitry also includes a switching circuitry configured to activate the first common-source amplifier and deactivate the second common-source amplifier to amplify the differential input signal by the fixed gain, and to activate the second common-source amplifier and deactivate the first common-source amplifier to amplify the differential input signal by the fixed gain with opposite sign.

Various embodiments relate to an adaptive linear driver, including: a continuous time linear equalizer (CTLE); a programmable transmit driver coupled with an output of the CTLE, wherein the transmit driver includes a first control port configured to receive a first control signal configured to adjust the output level of the programmable transmit driver; an output comparator coupled to an output of the programmable transmit driver, wherein the output comparator is configured to compare the output of the programmable transmit driver with a reference signal and to produce a first comparison signal; and a controller coupled to the output comparator and the first control port, wherein the controller produces a first control signal based upon the first comparison signal.

An optical link optimization includes receiving detected power outputs from one or more receivers in an optical network, wherein the detected power outputs include both a broad bandwidth power component and a low bandwidth power component; analyzing the detected power outputs to one or more of (1) balance power of a channel of interest for the one or more receivers and associated adjacent channels to a given channel of interest and (2) adjust filtering of the channel of interest for the one or more receivers and the associated adjacent channels to the given channel of interest; and configuring one or more components of the optical network to provide the one or more of (1) balance power and (2) adjust filtering.

A control system is configured to control an output power of a power amplifier. The control system is operable to detect when the power amplifier is in first state and responsively provide first additional bias to the power amplifier. The first additional bias assists or enables the power amplifier in increasing the output power. The control system is also operable to detect when the power amplifier is in a second state and responsively provide second additional bias to the power amplifier. The second additional bias assists or enables the power amplifier in increasing the amount of output power.

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 vibration generating apparatus comprises a vibration apparatus and a vibration driving circuit including a driving signal generator configured to supply a driving signal to the vibration apparatus, wherein the driving signal generator is configured to adjust a frequency-based gain compensation value based on at least one of a circuit internal temperature value of the vibration driving circuit and a temperature prediction value of the vibration apparatus corresponding to a current value of an n.sup.th driving signal, compensate for a frequency-based gain value based on the adjusted frequency-based gain compensation value, compensate for an (n+1).sup.th driving signal based on the compensated frequency-based gain value, and supply the compensated (n+1).sup.th driving signal to the vibration apparatus.

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.