This automatic gain control circuit is provided with a variable gain amplifier for amplifying a received signal, has a small circuit size, and makes it possible to reduce the effect of superimposed external noise input within the frequency bandwidth of a received signal. The automatic gain control circuit supplies the output of the variable gain amplifier to an analog/digital converter and comprises: a frequency selection circuit that is connected to the output of the analog/digital converter and that selects a signal within the frequency bandwidth of a received signal, said signal having a narrower bandwidth than the frequency bandwidth; and a control signal generation circuit that generates a control signal for the variable gain amplifier on the basis of the strength of the signal selected by the frequency selection circuit.

A radio frequency (RF) receiver circuit is disclosed. The RF receiver circuit includes a variable gain amplifier, configured to receive an input RF signal, and to generate an amplified RF signal based on the input RF signal, where a gain of the variable gain amplifier is variable. The RF receiver circuit also includes an RF level indicator circuit, configured to sample the amplified RF signal at non-periodic sampling intervals to generate a plurality of sampled RF signals, and to compare the sampled RF signals with one or more thresholds to generate a plurality of comparison result signals. The gain of the variable gain amplifier is determined based at least in part on the comparison result signals.

One embodiment is directed to controlling a gain for a receive signal path for receiving wireless signals. The following are repeatedly performed: determining an estimate of the total noise and interference in a received signal and determining a gain value for the receive signal path based on the estimate of the total noise and interference in order to maintain the digital data at a digital set point for a signal-to-interference-plus-noise-ratio (SINR) decoded with a highest modulation and coding scheme specified for the wireless channel. Another embodiment is directed to determining a received signal strength of the signals received at the receive signal path and determining a gain value for the receive signal path based on the received signal strength that maintains the digital data at a digital set point for a SINR sufficient to decode the MCS specified for the wireless channel.

An integrated circuit device is provided. In some examples, the integrated circuit device includes an amplifier stage that receives an input signal and a control signal and provides an amplified signal in response. A main path is coupled to the amplifier stage that receives the amplified signal and provides a first feedback signal corresponding to a signal strength of a data-bearing portion of the input signal. A control path also receives the amplified signal and provides a second feedback signal corresponding to a signal strength of the data-bearing portion and an interference component. A gain control circuit is coupled to the main path and the control path that receives the first and second feedback signals and provides the control signal in response to the feedback signals. In some such examples, the control path and main path include separate mixer stages with different performance characteristics.

An apparatus of user equipment (UE) includes a radio integrated circuit (IC), an adjustable external low noise amplifier (eLNA) external to the radio IC, and processing circuitry. The radio IC includes a receive signal circuit path including an adjustable gain internal low noise amplifier (iLNA), and a transmit signal circuit path including a digital-to-analog converter (DAC) circuit configured to convert digital signals to analog baseband signals for transmitting. The processing circuitry is configured to provide digital values of the digital signals to the DAC circuit and initiate adjusting gain of one or both of the iLNA and the eLNA according to the digital values.

An interrogation device, for locating a wireless device, includes a receiver and digital processing circuitry. The receiver includes one or more receiver stages having adjustable gains, and is configured to receive from the wireless device a signal that carries a packet including a direction-finding field, wherein, during reception of the direction-finding field, multiple different temporal sections of the received signal traverse different wireless channels due to switching among different antennas in the interrogation device or in the wireless device and thus have multiple different received-signal levels. The digital processing circuitry is configured, based on the multiple received temporal sections of the signal during reception of the direction-finding field, to (i) adapt the adjustable gains of the receiver stages and (ii) estimate a position of the wireless device.

An automatic gain control system and a control method, a power detector and a radio frequency receiver are provided, wherein the power detector includes: a detection circuit, having a first and second input terminals connected to respective first and second differential output terminals of the trans-impedance amplifier, and configured to sample a peak of a differential output signal of the trans-impedance amplifier along with a clock cycle and provide a differential detection signal at a first output node; a filter circuit converts energy of the differential detection signal obtained at the first output node into an output voltage, so that the power detector may be used to detect an output power of the trans-impedance amplifier and adjust, by a control logic unit, a gain or an output power of a low noise amplifier connected to a radio frequency signal.

A receiver or transmitter circuit includes a signal propagation path between a radio-frequency (RF) signal node and a baseband processing circuit. Variable gain circuitry is configured to vary a gain applied to a signal propagating between the RF signal node and the baseband processing circuit. The variable gain circuitry varies the gain via first, coarse steps as well as via second, fine steps. This facilitates fine matching of the gains experienced by signals propagating over the in-phase and the quadrature branches in the transmitter and/or receiver circuit.

A method performed by a radio network node for deciding an Automatic Gain Control (AGC) mode to be used for a received signal in a wireless communications network is provided. The radio network node estimates (301) a type of interference scenario affecting the received signal and obtains (302) information about channel quality of channels between the radio network node and connected wireless devices. Based on the estimated type of interference scenario and the obtained information about the channel quality, the radio network node dynamically decides (303) for the received signal, which AGC mode out of the following ACG modes to be used: —a slow AGC using a release timer for releasing an AGC state, —a fast AGC using a release timer for releasing an AGC state, and—a fast AGC using a trigger timer triggering an AGC state a first time interval before an interference period, and the release timer releasing the AGC state a second time interval after said interference period ends.

An automatic gain control circuit includes a control circuit for controlling a power detector, wherein the control circuit detects a power level change of an input signal and generates a control signal to the power detector so that the power detector can respond to the power level change of the input signal quickly.