Abstract: Embodiments of the present invention may provide a signal processor with a wide gain range. The signal processor may comprise at least a discrete step gain stage and a continuous variable gain amplifier (VGA) stage. The discrete step gain stage may comprise a programmable gain amplifier (PGA) (e.g., low noise amplifiers 1 and 2 (LNA1 and LNA2)). The VGA stage may provide a continuous range to compensate the LNAs gain steps. In one embodiment, the AGC controller enables an inherent hysteresis with the AGC step change if required.

Abstract: A system provides closed-loop gain control in a WCDMA mode and open loop control in an EDGE/GSM mode. Gain control is distributed across analog devices and a digital scaler in a wireless receiver. In the WCDMA mode, a loop filter generates an error signal that is forwarded to analog and digital control paths. The analog control path includes a first adder, a programmable hysteresis element, and a lookup table. The analog control signal is responsive to thresholds, which when used in conjunction with a previous gain value determine a new gain value. The digital control path includes a second adder, a programmable delay element, and a converter. A control word is responsive to a difference of the error signal, a calibration value, and the analog control signal. Blocker detection is provided in the WCDMA mode of operation. A controller sets system parameters using a state machine.

Abstract: An automatic gain control (AGC) method and system for a radio receiver are proposed in which the ACG comprises two AGC loops; a first loop controlling signal gain in the analog portion of the radio receiver, a second loop controlling gain in the digital domain after digitization of the received signal. The analog AGC loop has a slower response time than the digital AGC loop. When applied to a multi-branch diversity receiver, each branch has its own digital AGC loop, but the analog gain can be common to all branches, based on measurement of the analog signal in each branch.

Abstract: Aspects of a method and system for integrated blocker detection and automatic gain control are provided. In this regard, a communication device may generate one or more first signal strength indications based on a strength of a received signal at a first point in the analog front-end of the communication device. The communication device may generate one or more second signal strength indications based on a strength of the received signal at a second point in a digital processing module of the communication device. The first point in the analog front-end may be an input or an output of a down-conversion mixer. The second point in the digital processing module may be an output of an analog-to-digital converter or an output of a channel selection filter. The communication device may control, utilizing the first signal strength indication(s) and the second signal strength indication(s), a gain of one or more components of the communication device.

Abstract: Provided are a receiving apparatus and method for a wireless communication system using multiple antennas. A receiving method for a wireless communication system using multiple paths, the receiving method comprising: receiving signals through a predetermined number of multiple paths; sensing a carrier according to saturation state degrees of the signals, and providing saturation state information; calculating automatic gain components of the received signals by using the received signals and the saturation state information of the received signals; and performing a noise matching process to amplify noises on the predetermined multiple paths according to the automatic gain components during a predetermined period.

Abstract: An automatic gain control apparatus for a wireless receiver, including multiple variable gain amplifiers, one variable gain amplifier provided for each one of multiple receive chains and a gain controller to control a gain of the variable gain amplifiers provided for the plurality of receive chains. The gain controller includes multiple output level measurement units to measure an output level of a corresponding receive chain; a common gain determination unit to determine a common gain for each of the variable gain amplifiers based on a statistical value obtained from the output levels; multiple adjusted gain determination units, each adjusted gain determination unit determining an adjusted gain independently for each variable gain amplifier within a range narrower than the range of the common; and a gain setting unit to set a gain to each of the variable gain amplifiers based on the common gain and the adjusted gain.

Abstract: An FM receiver includes a receiving unit that receives a signal from a broadcasting station and outputs a receiving signal, an equalizer that equalizes the receiving signal by using a calculated weight, and obtains an equalized output signal, a demodulator that demodulates the equalized output signal to reproduce the signal from the broadcasting station, a detection unit that observes size of the calculated weight to detect a capture state with respect to an undesired broadcasting station and generates a capture detection signal, and a weight setting unit that sets the calculated weight with respect to the equalizer at a steady state, and sets a specific weight for temporarily setting the equalizer in a through state when the capture detection signal is generated.

Abstract: The present invention discloses apparatus and method for fast and robust automatic gain control (AGC). By using the power statistics and/or the amplitude statistics of multiple pairs of signed ADC outputs, the additional gain control can be determined and included in a statistics-aided AGC to successfully complete the AGC function for a received signal having a dynamic range up to 100 dB within a few micro-seconds.

Abstract: An automatic gain control loop disposed in a receiver is adapted to compensate for varying levels of out of band interference sources by adaptively controlling the gain distribution throughout the receive signal path. One or more intermediate received signal strength indicator (RSSI) detectors are used to determine a corresponding intermediate signal level. The output of each RSSI detector is coupled to an associated comparator that compares the intermediate RSSI value against a corresponding threshold. The take over point (TOP) for gain stages is adjusted based in part on the comparator output values. The TOP for each of a plurality of gain stages may be adjusted in discrete steps or continuously.

Abstract: A technique for controlling operation of a communication subsystem is described. The subsystem is set to a first wake-up mode of operation, during which a state value from the system is read and stored in memory. The subsystem is then set to a sleep mode of operation after the first wake-up mode of operation, and to a second wake-up mode of operation after the sleep mode of operation. The stored state value is then read from the memory, where the subsystem is set to operate based on the read state value during a warm-up period of the second wake-up mode of operation.

Abstract: A system provides closed-loop gain control in a WCDMA mode and open loop control in an EDGE/GSM mode. Gain control is distributed across analog devices and a digital scaler in a wireless receiver. In the WCDMA mode, a loop filter generates an error signal that is forwarded to analog and digital control paths. The analog control path includes a first adder, a programmable hysteresis element, and a lookup table. The analog control signal is responsive to thresholds, which when used in conjunction with a previous gain value determine a new gain value. The digital control path includes a second adder, a programmable delay element, and a converter. A control word is responsive to a difference of the error signal, a calibration value, and the analog control signal. Blocker detection is provided in the WCDMA mode of operation. A controller sets system parameters using a state machine.

Abstract: Disclosed is a radio frequency (RF) receiver for receiving a communication channel modulated on one or more carrier frequencies. The receiver may include a gain adjustable RF amplifier, a wideband signal power measurement circuit, and control logic. The control logic may be adapted to use outputs of one or more measurement circuits to classify interfering signals based on measured signal power and spectral proximity to the one or more channel carrier frequencies, and to adjust the gain of the radio frequency amplifier based on the classification.

Abstract: Disclosed is a radio frequency (RF) receiver for receiving a communication channel modulated on one or more carrier frequencies. The receiver may include a gain adjustable RF amplifier, a wideband signal power measurement circuit, and control logic. The control logic may be adapted to use outputs of one or more measurement circuits to classify interfering signals based on measured signal power and spectral proximity to the one or more channel carrier frequencies, and to adjust the gain of the radio frequency amplifier based on the classification.

Abstract: A system and technique for providing to flexible, programmable frequency estimators and spectrum analyzers that can operate over extremely large bandwidths and yet provide high spectral resolution are described. The system and technique may include a cascaded super-heterodyne apparatus for estimating a frequency and a bandwidth of signals proximate in frequency to a desired signal, a tunable filter coupled to an input of a receiver, and a tuner which receives a signal from said cascaded super-heterodyne apparatus and tunes the filter to filter out unwanted signals from the receiver.

Abstract: A radio frequency (RF) transceiver integrated circuit (IC) includes a plurality of baseband Tx sections, a plurality of RF Tx sections, a plurality of RF Rx sections, and a plurality of baseband Rx sections. The RF transceiver IC further includes a static digital interface, a dynamic digital interface, and gain control, distribution, and buffering circuitry. Static digital interfaces are operable to receive static gain control commands from a coupled baseband processor. The dynamic digital interface is also operable to receive dynamic gain control commands from the coupled baseband processor. The gain control, distribution, and buffering circuitry is operable to apply the static gain control commands and dynamic gain control commands to at least some of the plurality of baseband Tx sections, the plurality of RF Tx sections, the plurality of RF Rx sections, and the plurality of baseband Rx sections.

Abstract: A receiving apparatus includes: a signal-level detecting unit detecting a signal level of an input signal; a first signal-level converting unit including amplifiers, capturing the input signal and converting a signal level of the input signal; a switching unit switching an output of a converted level signal; a switching control unit selecting a specific amplifier and controlling the switching unit to select an output signal from the selected amplifier; a band-pass filter allowing only a predetermined frequency hand in the switched signal to pass; a second signal-level converting unit converting a signal level of an output signal from the amplifier into a predetermined signal level at which S/N of a mixer is maximized; the mixer mixing the converted signal passed through the band-pass filter, and an oscillation signal to generate an intermediate frequency signal; and a demodulating unit demodulating the intermediate frequency signal.

Abstract: A method for use in a digital communications receiver for controlling an input signal level (200) into an analog-to-digital converter (ADC) initially receives a sample sequence (201) where a threshold crossing rate is measured as a percentage samples of an input signal that exceed the threshold (203). The error between the measured threshold crossing rate and a desired reference threshold crossing rate is calculated (205) and an error signal is then utilized in a feedback loop to control the receiver gain such that the error is reduced (207).

Abstract: A communication device reads and stores in memory a state value which was utilized for operating a communication subsystem during a wake-up period of the communication subsystem. The device then causes the communication subsystem to enter into a sleep mode. Subsequently, the device causes the communication subsystem to exit from the sleep mode and enter into a current wake-up period. The stored state value is provided to the communication subsystem for use in operating the communication subsystem during a warm-up period of the current wake-up period. After the warm-up period of the current wake up period, a current state value is provided from a state controller to the communication subsystem for use in operating the communication subsystem during the wake up period. The current state value is determined based on a detected signal level of a current signal received in the communication subsystem.

Abstract: Provided are apparatus and method for receiving signals in a wireless communication system.

Abstract: Methods, systems, and machine-readable code for optimizing transmit power of a power amplifier using a Vbat monitor are disclosed and may comprise adjusting the gain of gain stages in a transmit path based on a control signal that is a function of a supply voltage signal, among other variables, derived from a supply voltage that may be used to power a transmit path. The supply voltage signal may be received from a power management unit or derived directly from a battery or other supply. The supply voltage signal may be compared to a reference signal, the result of which may be utilized to generate the control signal. The values for the control signals may be determined over a range of supply voltages and stored in a lookup table.

Abstract: An enhanced programmable automatic level control loop comprising an input for receiving an input RF signal; a level modulator, wherein the level modulator receives the input RF signal and a control signal and wherein the level modulator produces a first signal; a mixer that receives the first signal and mixes it with an LO signal to produce a second signal; a programmable attenuator that receives the second signal and produces an output signal; a level detector that monitors RF power of the output signal and produces a DC voltage proportional to the RF power; and wherein the DC voltage is received at a loop amplifier which produces the control signal.

Abstract: Techniques for controlling a gain state of a wireless receiver involve causing the wireless receiver to enter into a sleep mode; causing the wireless receiver to exit from the sleep mode and enter into a wake-up period; providing, via a multiplexer, a stored gain control state value to the wireless receiver for use during a warm-up period of the wake-up period, the stored gain control state value being previously read from a gain controller during a previous wake-up period of the wireless receiver; and after the warm-up period of the wake up period, providing, via the multiplexer, a current gain control state value from the gain controller to the wireless receiver for use during the wake up period, the current gain control state value being based on a signal level of a currently-received signal in the wireless receiver.

Abstract: Systems and methods for sharing an AGC loop between a wireless data demodulator and a spectrum analysis module that operates simultaneously with the data demodulator. In one embodiment, a predetermined hold time prevents the AGC loop from changing gain too often, thereby allowing the spectrum analysis module to collect reliable data. In another embodiment, the hold time may be extended to coincide with a spectrum analysis event, such as a boundary of an FFT block. In still another embodiment, an FFT valid signal is provided such that collected FFT blocks can be designated as suspect and then subsequently processed accordingly.

Abstract: A receiving apparatus may achieve optimal RF and IF gain control while suppressing saturated amplification due to interference. The receiving apparatus includes an RF variable gain Amp that amplifies a received RF signal, a mixer that converts an output signal of the RF variable gain Amp into an IF signal, an IF variable gain Amp that amplifies the IF signal, a demodulator that demodulates an output signal of the IF variable gain Amp, and an AGC circuit. The AGC circuit sets a period of gain control for the RF variable gain Amp to be shorter than a period of gain control for the IF variable gain Amp when gains of the RF variable gain Amp and the IF variable gain Amp are controlled based on the output signal of the IF variable gain Amp.

Abstract: Methods and apparatus to perform radio frequency (RF) analog-to-digital conversion are described. According to one example, a receiver includes an amplifier to amplify received analog RF signals and a mixer-free circuit for converting the received analog RF signals to digital signals.

Abstract: The invention provides a signal amplifying stage, used in a signal receiver. The signal amplifying stage has: a fixed-gain low noise amplifier (LNA), amplifying an input signal; a variable-gain LNA (VG-LNA) array, amplifying the input signal, including a plurality of parallel VG-LNAs, the VG-LNA array being parallel with the fixed-gain LNA; a variable-gain amplifier (VGA), being in series with the fixed-gain LNA and the VG-LNA array, for amplifying output signals from the fixed-gain LNA and the VG-LNA array to generate an output signal; an attenuator, being in parallel with a combination of the fixed-gain LNA, the VG-LNA array and the VGA, for attenuating the input signal to generate the output signal; and a control loop, coupled to the VGA and the attenuator, for detecting power levels of the output signal to enable and control the fixed-gain LNA, the VG-LNA array, the VGA and the attenuator.

Abstract: A radio receiver such as a frequency modulation (FM) receiver, for example, includes a radio frequency (RF) amplifier having an adjustable gain output. The RF amplifier may be configured to receive and amplify an incoming RF signal. The receiver also includes an intermediate frequency (IF) amplifier having an adjustable gain output. The IF amplifier may be configured to receive and amplify an IF signal that corresponds to the RF signal. The receiver also includes a gain control unit that is coupled to the RF amplifier and the IF amplifier. The gain control unit may be configured to independently adjust the gain of each of the RF amplifier and the IF amplifier, dependent upon a peak output level of both the RF amplifier and the IF amplifier.

Abstract: Methods and apparatus to perform radio frequency (RF) analog-to-digital conversion are described. According to one example, a receiver includes an amplifier to amplify received analog RF signals and a mixer-free circuit for converting the received analog RF signals to digital signals.

Abstract: Reception levels are measured in respective branches to compare the results of the measurements with one another to select the result of the measurement of a maximum reception level which is the highest reception level. The gains of variable gain amplifiers (6, 7) of all the branches including variable gain amplifiers (6, 7) included in a branch corresponding to the maximum reception level are adjusted to the same value such that output levels of the variable gain amplifiers (6, 7) are set to a preset target level.

Abstract: A radio signal receiver in which a RF-receiving unit 12 converts a radio received signal to a baseband signal, an AD-conversion unit 15a, 15b converts that baseband received signal to a digital signal, and a baseband-processing unit 16 uses the digital signal to perform specified baseband processing, and in which an average-interference-level-measurement unit (SIR measurement unit) 17 measures the average interference level of the received signal, an amp-gain-adjustment unit 18 sets the gain so that a fixed binary value becomes that measured average interference level, and a variable-gain amp 14a, 14b controls the reception level of the received signal by that set gain.

Abstract: A purpose of the present invention is to provide an acoustic apparatus capable of automatically setting a gain which is suitable for both an averaged signal strength of input voice and an instantaneous signal strength thereof, capable of easily recognizing an effect by a user, which is achieved by switching a turn-ON and a turn-OFF of an automatic gain variable operation, and further capable of readily recognizing a change in gain values by the user. The acoustic apparatus is provided with a gain setting unit (20) for setting a gain from an averaged voice strength within a predetermined time period, and another gain setting unit (22) for setting a gain in response to an instantaneous signal strength thereof; and the acoustic apparatus adjusts a signal strength of an audio input signals (Si) based upon a gain “C” obtained by multiplying a gain “A” by another gain “B.

Abstract: A radio frequency (RF) transceiver integrated circuit (IC) includes a plurality of baseband Tx sections, a plurality of RF Tx sections, a plurality of RF Rx sections, and a plurality of baseband Rx sections. The RF transceiver IC further includes a static digital interface, a dynamic digital interface, and gain control, distribution, and buffering circuitry. Static digital interfaces are operable to receive static gain control commands from a coupled baseband processor. The dynamic digital interface is also operable to receive dynamic gain control commands from the coupled baseband processor. The gain control, distribution, and buffering circuitry is operable to apply the static gain control commands and dynamic gain control commands to at least some of the plurality of baseband Tx sections, the plurality of RF Tx sections, the plurality of RF Rx sections, and the plurality of baseband Rx sections.

Abstract: A gain control apparatus in a receiver of multiband OFDM system includes: an amplifier amplifying a received signal based on a first auto gain control signal; an analog-to-digital converter for converting the amplified signal into a digital signal; band reception signal extractor for extracting a signal of a desired reception band from the converted digital signal for each reception band, and controlling gain of the extracted signal according to a second auto gain control signal; a reception power detector for detecting a reception power value of whole band from the converted digital signal; and a multiband integration baseband processor for generating the first auto gain control signal by using the detected reception power value of the whole band, and generating the second auto gain control signal to be provided to the band reception signal extraction units, resource allocation information for each band and a reception power for each reception band.

Abstract: A tuner down-converts a Radio Frequency (RF) wireless signal and outputs the converted signal. The tuner compensates for a TOP depending on a temperature and: detects a received signal strength depending on a RF output of the tuner and transmitting the detected strength to a gain control unit; measures an operating temperature of the tuner and transmits the measured temperature value; receives the measured temperature value to compare the received temperature value with a reference TOP value, compensating compensates for the TOP value depending on variation in temperature and outputting outputs the compensated value; and receives the compensated value to control the RF output based on the TOP value and the received signal strength.

Abstract: A signal gain control circuit. A gain stage receives and amplifies an analog signal by a first gain factor adjusted by a gain adjusting signal in a periodic manner with a first period, and outputs an amplified signal. An analog to digital converter converts the amplified signal to a first digital signal comprising a stream of samples. An amplifying device adjusts a second gain factor in a periodic manner with a second period in accordance with a characteristic metric of the distribution of the first digital signal and multiplying the first digital signal by the second gain factor to generate a second digital signal. A first gain adjusting device detects a strength of the second digital signal and generates the gain adjusting signal according to the signal strength of the second digital signal in a periodic manner with the first period.

Abstract: A received low-frequency standard radio wave, which is an amplitude modulation signal, is converted to an intermediate frequency signal Sa, and is output to a detection circuit and an AGC circuit. The detection circuit and AGC circuit generates an RF control signal Sf1 and IF control signal Sf2 from the input intermediate frequency signal Sa, and controls an RF control circuit and IF control circuit by outputting the generated RF control signal Sf1 and IF control signal Sf2 to the RF control circuit and IF control circuit. By this a radio wave reception device can speed up AGC operation.

Abstract: A receiver for processing a signal comprises a first amplifier circuit and a second amplifier circuit. The first amplifier circuit is operated in association with a first gain profile. The second amplifier circuit is operated in association with a second gain profile. The receiver further comprises a gain control circuit that determines a quality indicator associated with a modulated signal. The gain control circuit adjusts the first gain profile and the second gain profile based at least in part upon the determined quality indicator.

Abstract: An apparatus (20) such as a television signal receiver provides an AGC function by using multiple feedback sources which provide both narrow band and wide band AGC signals in an adaptive manner. According to an exemplary embodiment, the apparatus (20) includes a tuner (10, 15, 20, 25, 30) operative to generate first and second IF signals. A first demodulator (40) is operative to generate a first AGC signal responsive to the first IF signal. A second demodulator (50) is operative to generate a second AGC signal responsive to the second IF signal. A wide band AGC detector (60) is operative to generate a third AGC signal responsive to at least one of the first and second IF signals. A switch (70) is operative to selectively provide one of the first, second and third AGC signals to the tuner (10, 15, 20, 25, 30) responsive to a predetermined condition.

Abstract: An embodiment of the present invention provides a method of closed loop MIMO calibration in a wireless communication system, comprising detecting that station calibration is obsolete and requires calibration, determining a range of automatic gain control which the station wants to calibrate and determining a list of transmission power for an Access Point (AP) in communication with the station, initiating by the station the calibration by sending the power list and N channel sounding preambles, where N is the number of transmit antennas at the station; and sending back by the AP a channel matrix and L sets of channel sounding preambles with a different transmission power level for each set, where L is the number of entries in the power list.

Abstract: An Automatic Gain Control (AGC) circuit as used in a digital receiver that utilizes a main loop filter that is of a relatively wide bandwidth. A pre-filter, wideband variance is determined from the input digital signal, and a post-filter, narrowband variance is also determined. The wideband and narrowband variances are then compared to determine if the wideband signal power indicates a variance level that is too great to permit normal loop operation. By reapplying this difference in the power levels to the filter output as needed, such as by a scaling operation, the loss in dynamic range is effectively recovered. In a preferred embodiment, an adjustable gain input amplifier feeds an intermediate frequency (IF) signal to an analog-to-digital converter (ADC). The digitized IF signal is then down-converted to a baseband frequency and subjected to digital filtering. A narrowband sample variance (PN) of the digitally filtered (narrowband) data is then determined.

Abstract: A method and system is disclosed for perform receiver gain control. A pilot signal is transmitted prior to each transmit period to facilitate an initial gain setting for a corresponding receiver period. This pilot signal has known properties and requires a much smaller receiver dynamic range than the rest of the traffic. An initial gain setting is derived based on the pilot signal received at a beginning of a corresponding receive period. A gain setting for traffic signals is then generated following the pilot signal in the receive period based on the initial gain setting.

Abstract: A signal amplifier system is provided for a mobile or portable broadcast receiver. The signal amplifier system includes an operational circuitry, a signal generator and a voltage supply. The signal generator receives a field strength signal that indicates a field strength of at least one broadcast signal. The signal generator outputs a supply voltage control signal based on the field strength signal. The voltage supply provides one of a first supply voltage and a second supply voltage to the operational circuitry in accordance with the supply voltage control signal.

Abstract: A radio receiver such as a frequency modulation (FM) receiver, for example, includes a radio frequency (RF) amplifier having an adjustable gain output. The RF amplifier may be configured to receive and amplify an incoming RF signal. The receiver also includes an intermediate frequency (IF) amplifier having an adjustable gain output. The IF amplifier may be configured to receive and amplify an IF signal that corresponds to the RF signal. The receiver also includes a gain control unit that is coupled to the RF amplifier and the IF amplifier. The gain control unit may be configured to independently adjust the gain of each of the RF amplifier and the IF amplifier, dependent upon a peak output level of both the RF amplifier and the IF amplifier.

Abstract: An apparatus, a carrier medium storing instructions to implement a method, and a method for controlling the gain of a radio receiver for receiving packets of information in a wireless network. The receiver is connected to an antenna subsystem and has receive signal path including a plurality of sections including a first section coupled to the antenna subsystem and a next section. Each section has an adjustable gain and is able to provide a measure of the signal strength at its output. The method includes waiting for a start of packet indication, providing a measure of the signal strength at the output of the first section and the next section, and adjusting the gains of the first and the next sections using the provided measured signal strengths. In one embodiment, the receive signal path includes a filter, the provided measure for the first section is before the filter, and the provided measure for the second section is after the filter.

Abstract: A diversity receiver system includes a plurality of radio receivers that each provide a uniquely associated receiver output signal and a uniquely associated receiver control signal indicative of the amount of gain applied by the associated radio receiver to create the uniquely associated receiver output signal. A selection mechanism receives the receiver control signals, and determines which of the radio receivers has applied the smallest gain correction to its associated receiver output signal, and provides a diversity receiver output signal indicative of the receiver output signal associated with the receiver that applied the smallest gain correction.

Abstract: A transmitter for a portable radio communication apparatus comprising a modulator having first port for inputting a baseband signal and a second port for inputting a local oscillator signal, and including means for rectifying the input local oscillator signal to provide a conductance waveform at a multiple of the local oscillator signal, and means for mixing the baseband signal with the conductance waveform at said multiple of the local oscillator signal frequency for up-converting the baseband signal to a radio frequency modulated carrier, the transmitter including means for controlling the gain of the modulator thereby to control the output level of the modulator.

Abstract: A speed-up mode control system is operative to generate a speed-up mode signal based on a gain control signal from associated digital circuitry. The speed-up mode signal controls electronics associated with one or more amplifiers to facilitate settling time of an output signal of the amplifier(s) that occurs when the gain of the amplifier changes. The gain control signal also can be delayed to provide a delayed version of the gain control signal for controlling gain of the amplifier(s).

Abstract: A wireless signal amplification system including amplification apparatus (6) consisting of numerous different amplifiers (61 to 6n) which are distributed in an analogue processing chain (4). Also, a converter (12) for converting analogue signals into digital signals which, at input, are connected to the outlet of the analogue processing chain (4) and, at output, are connected to at least the gain control circuit (16) of the amplification apparatus (6) according to a value that is representative of a characteristic of the wireless signal (1). In this way, sampling of the wireless signal (1) by the converter (12) is optimized. The gain control circuit (16) establishes an average gain control signal (18), and also has, for each of the amplifiers (61 to 6n), a device for calculating an individual gain control signal (20i to 20n) according to a transfer function (H1 to Hn) which is specific to each amplifier and which is applied to the average gain control signal.

Abstract: An Automatic Gain Control (AGC) circuit as used in a digital receiver that utilizes a main loop filter that is of a relatively wide bandwidth. A pre-filter, wideband variance is determined from the input digital signal, and a post-filter, narrowband variance is also determined. The wideband and narrowband variances are then compared to determine if the wideband signal power indicates a variance level that is too great to permit normal loop operation. By reapplying this difference in the power levels to the filter output as needed, such as by a scaling operation, the loss in dynamic range is effectively recovered. In a preferred embodiment, an adjustable gain input amplifier feeds an intermediate frequency (IF) signal to an analog-to-digital converter (ADC). The digitized IF signal is then down-converted to a baseband frequency and subjected to digital filtering. A narrowband sample variance (PN) of the digitally filtered (narrowband) data is then determined.

Abstract: In order to rapidly control the gains of a plurality of variable gain amplifiers VGAs, each of gain control circuits is configured to determine a gain to be set therein, based on gain control information received from other gain control circuits existing in its preceding stage or stages and the signal level detected by a level detector circuit connected thereto. By carrying out such gain control, a total application gain is stabilized more quickly by gain control. Therefore, even in receiving systems that the preparation period for reception is very short, desired gain control is achieved within this period and stable data reception can be performed.