An amplifier includes a P-type transistor and an N-type transistor that are connected in series, an operation amplifier, a transformer, and a variable attenuator. In the operation amplifier, an output terminal is coupled to a gate side of one of the P-type transistor and the N-type transistor, one of an inverting input terminal and a non-inverting input terminal is coupled to drain sides of both of the P-type transistor and the N-type transistor, and a reference voltage is to be applied to the other of the inverting input terminal and the non-inverting input terminal. In the transformer, a primary coil is coupled to a source side of one of the P-type transistor and the N-type transistor. The variable attenuator is provided between a secondary coil and gate terminals of both of the N-type transistor and the P-type transistor.

Example embodiments provide a process that includes one or more of receiving an audio signal from a feedback path of a feedback compressor circuit, determining whether an auxiliary attenuation value applied to the feedback compressor circuit has changed since a last audio signal was received, responsive to determining the auxiliary value has changed, determining a current operational state value of the LPF needs to be modified based on the changed auxiliary attenuation value, modifying the operational state value of the LPF, and applying the audio signal to the modified LPF.

The present disclosure relates to a circuit including an input terminal configured to receive a first signal at a first frequency; a demodulation chain connected to the input terminal and including a low-noise amplifier having an input coupled to the terminal; a controllable variable impedance connected between a first node and a node configured to receive a reference potential, the first node being connected to the input terminal and/or to the amplifier input; and a current source configured to deliver a current at the first frequency to the first node.

A technology is described for adjusting repeater gain based on user equipment need. A downlink path of the repeater can be deactivated. A deactivated throughput value can be received from the UE for data received at the UE in a selected time period. The downlink amplification path of the repeater can be activated. An activated throughput value for data received at the UE in the selected time period can be received from the UE. A difference can be determined between the deactivated throughput value and the activated throughput value. A repeater gain value can be reduced or bypassed when the deactivated throughput value is greater than the activated throughput value by a selected threshold value.

The present application relates to a gain control method and an apparatus, comprising an automatic gain controller. An input power of a PSS in an input signal is detected in real time, a rated power of a downlink PSS that acts as a gain control threshold of the automatic gain controller is acquired, and the automatic gain controller is controlled to adjust a value of gain attenuation according to magnitudes of the input power of the PSS and the rated power of the downlink PSS, which is used to adjust an uplink gain and a downlink gain.

A number of biasing circuits for amplifiers including voltage controlled amplifier is presented. Also a number of field effect transistor circuits include voltage controlled attenuators or voltage controlled processing circuits. Example circuits include modulators, lower distortion variable voltage controlled resistors, sine wave to triangle wave converters, and or servo controlled biasing circuits.

Multi-mode broadband low noise amplifiers (LNAs) are disclosed herein. In certain embodiments, an LNA includes a first amplification stage and a second amplification stage having a lower gain than the first amplification stage. The LNA is operable in a plurality of operating modes including a first mode in which the first amplification stage and the second amplification stage operate in a cascade to amplify a radio frequency (RF) receive signal, and a second mode in which the first amplification stage amplifies the RF receive signal and the second amplification stage is bypassed.

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.

An amplifier circuit includes a first terminal and a second terminal, an amplifier disposed in a first path connecting the first terminal and the second terminal, a first switch circuit disposed in the first path between the amplifier and the second terminal, an attenuator disposed in the first path between the amplifier and the first switch circuit, and a second switch circuit disposed in a second path that is connected to the first terminal and the second terminal while bypassing the amplifier, the attenuator, and the first switch circuit.