A method of operating a radio receiver device comprises receiving a plurality of signals with a plurality of corresponding frequencies; applying respective gains to each of the plurality of signals; and storing the gain applied to each signal and its corresponding frequency. The method comprises subsequently receiving a further signal with a further frequency; and applying a further gain to the further signal. The further gain is determined using at least one of the stored gains according to a difference between the further frequency and at least one of the plurality of corresponding frequencies.

A method for controlling gain of a line amplifier on a cable, the method comprising selecting an unused carrier frequency; transmitting a pulsed pilot signal on the unused carrier frequency into the cable; determining a pilot signal output strength by measuring signal strength of the pilot signal after amplification by the line amplifier; comparing the pilot signal output strength with a target signal strength to determine a difference; and adjusting the gain of the line amplifier corresponding to the difference.

A signal adjusting circuit and a receiving end circuit using the same are provided. The signal adjusting circuit is adapted to a peak detector, and includes a first amplifier and a first feedback circuit. The first amplifier receives a first input signal, and amplifies the first input signal to output a first output signal. The first feedback circuit is connected between a first input terminal and a first output terminal of the first amplifier, and is configured to determine a first gain of the first output signal. The peak detector is connected to a first output node of the first feedback circuit, so as to receive a first detection signal and detect a peak value of the first detection signal. The peak detector has a predetermined power input range, and the first feedback circuit keeps the first detection signal within the predetermined power input range.

Techniques are provided for automatic gain control processing to reduce adverse effects associated with clipped samples resulting from conversion of analog signals to digital signals. A methodology according to an embodiment includes identifying a clipped sample of the digital signal, for example by comparison of the digitized sample values to a threshold value associated with a full scale value of the converter. The method also includes applying a window function to portions of the digital signal. The window function is configured to attenuate samples of the digital signal within a region centered on the identified clipped sample. A Hilbert finite impulse response (FIR) filter may be applied to the digital signal prior to applying the window function. Parameters of the window function are selected based on frequency response characteristics of the FIR filter and on signal to noise ratio requirements of an application that receives the windowed digital signal.

A feed forward echo cancellation device includes a first impedance circuit, a second impedance circuit, and an echo cancellation current generator circuit. The first impedance circuit is configured to output a first current to a node in response to a transmission current. The second impedance circuit is configured to output a second current to a node in response to the transmission current. The echo cancellation current generator circuit is configured to drain an echo cancellation current from the node. The node is connected to an input terminal of a programmable gain amplifier circuit via a gain control circuit, and the gain control circuit is configured to set a gain of the programmable gain amplifier circuit.

A receiver front-end includes a first variable-gain amplifier that performs attenuation; a continuous time linear equalizer coupled to the input or output of the first variable-gain amplifier, wherein a combination of the first variable-gain amplifier and the continuous time linear equalizer produces a processed signal; a plurality of track-and-hold circuits that sample the processed signal in an interleaved manner; and a plurality of second variable-gain amplifiers receiving input signals from the plurality of track-and-hold circuits respectively.

Methods and systems for optimizing amplifier operations are described. The described methods and systems particularly describe a feed-forward control circuit that may also be used as a feed-back control circuit in certain applications. The feed-forward control circuit provides a control signal that may be used to configure an amplifier in a variety of ways.

A power amplifying circuit includes multi-stage power amplifiers, bias circuits, and a control circuit. The bias circuits output corresponding bias currents based on corresponding control currents. The control circuit outputs the control currents to the bias circuits based on a control voltage. The power amplifiers include a first stage of first and second power amplifiers connected in parallel electrically. The bias circuits include first and second bias circuits. The control circuit includes first and second current output units. The first current output unit outputs, to the first bias circuit, a first control current which has a first current value when the control voltage is a first threshold voltage, and which increases linearly with the control voltage, and the second current output unit outputs, to the second bias circuit, a second control current, having a second constant current value, when the control voltage is the first threshold voltage or greater.

Provided are automatic level control (ALC) circuit, signal source, method for controlling signal source output power, and storage medium. The ALC circuit includes: at least two stages of ALC loops, each ALC loop including an amplifier, a coupler, a power detector, and an attenuation control module connected sequentially. An output end of an adjustable attenuator is connected to an input node of first stage of ALC loop; an output node of each stage of ALC loop, other than last stage of ALC loop, is connected to a normally on end of a two-way single-on switch, a first gating end of the two-way single-on switch is connected to an input node of a next stage of ALC loop, and the output node of the last stage of ALC loop and a second gating end of each two-way single-on switch are connected to an output end of the ALC circuit.

Examples disclosed herein relate to a high gain active relay antenna system. The active relay antenna system comprises a first antenna pair having a first receive antenna and a first transmit antenna to communicate wireless signals in a forward link from a base station to a plurality of users; and a second antenna pair having a second receive antenna and a second transmit antenna to communicate wireless signals in a return link from the plurality of users to the base station. The active relay antenna system further comprises a first active relay section and a second active relay section to provide for adjustable power gain in the wireless signals.