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 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.

Device and method are disclosed for downlink gain compensation at a radio unit. According to an embodiment, the device comprises a pre-distortion circuit, a digital gain adjuster, a gain determiner and a first gain controller. The pre-distortion circuit is configured to generate and apply a pre-distortion to an input signal. The digital gain adjuster is configured to apply an adjustable gain to an output signal from the pre-distortion circuit. The gain determiner is configured to determine a gain difference between a target downlink gain and current downlink gain. The first gain controller is configured to control the digital gain adjuster based on the gain difference. A radio unit comprising the device is also disclosed.

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.

Device and method are disclosed for downlink gain compensation at a radio unit. According to an embodiment, the device comprises a pre-distortion circuit, a digital gain adjuster, a gain determiner and a first gain controller. The pre-distortion circuit is configured to generate and apply a pre-distortion to an input signal. The digital gain adjuster is configured to apply an adjustable gain to an output signal from the pre-distortion circuit. The gain determiner is configured to determine a gain difference between a target downlink gain and current downlink gain. The first gain controller is configured to control the digital gain adjuster based on the gain difference. A radio unit comprising the device is also disclosed.

A power amplification system includes a Power Amplifier (PA) for amplifying an input RF signal. An adaptive bias circuit is configured to adaptively set a bias of the PA. The adaptive biasing circuit includes a gain expansion circuit, a gain compression circuit and a biasing circuit. The gain expansion circuit derives a gain-expansion control signal from the input RF signal. For a first sub-range of the input RF signal, the gain-expansion control signal has a larger dynamic range than the input RF signal. The gain compression circuit derives a gain-compression control signal from the input RF signal. For a second sub-range of the input RF signal having higher power levels than the first sub-range, the gain-compression control signal has a smaller dynamic range than the input RF signal. The biasing circuit sets the bias of the PA responsively to the gain-expansion control signal and the gain-compression control signal.

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.

Various methods and circuital arrangements for protection of an RF amplifier are presented. According to one aspect, the RF amplifier is part of switchable RF paths that include at least one path with one or more attenuators that can be used during normal operation to define different modes of operation of the at least one path. An RF level detector monitors a level of an RF signal during operation of any one of the switchable RF paths and forces the RF signal through the at least one path with one or more attenuators while controlling the attenuators to provide an attenuation of the RF signal according to a desired level of protection at an input and/or output of the RF amplifier.

At least one embodiment relates to a radio-frequency (RF) power amplifier system for amplifying a first RF signal. The RF power amplifier system includes a RF power amplifier being configured to amplify a second RF signal. The RF power amplifier system also includes a control loop for controlling a power level of the second RF signal. The control loop includes a RF output power determining unit for determining a power level of the amplified second RF signal. The control loop also includes a gain determining unit for determining an actual large signal gain based on the determined power level of the amplified second RF signal and a power level of the second RF signal. Further, the control loop includes an attenuator for attenuating the first RF signal and for providing the attenuated first RF signal to the RF power amplifier as the second RF signal.

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.