Abstract: A radio frequency (RF) receiver utilizing dynamic power management for administration of power consumption. The RF receiver includes an RF antenna, an RF full band filter, an RF amplifier, an RF sub-band filter, a first local oscillator, an RF mixer, a first IF amplifier, an IF wide band filter, a second local oscillator, an IF mixer, two secondary IF amplifiers, an IF narrow band filter, a digital signal processing subsystem, three power sensors, and a control logic subsystem. Based on its location in the system, each power sensor has a unique threshold setting that is set just below a total RF power level where desired signal degradation might occur. The control logic subsystem utilizes outputs of the power sensors to detect a total RF power present due to interfering signals plus a desired signal within an entire bandwidth present at each stage and dynamically manages power by adjusting bias of each stage accordingly via its bias control outputs.

Abstract: By A/D converting a signal output from a mixer (4) and inputting the A/D converted signal to a DSP (8), and generating AGC control data (DL) corresponding to a level of the signal to control a gain of an LNA (3) in such a manner that a voltage input to an A/D converting circuit (7) is lower than a full scale voltage of the A/D converting circuit (7), it is possible to prevent a signal having an excessively high level beyond a dynamic range of the A/D converting circuit (7) from being input to the A/D converting circuit (7). By controlling the gain of the LNA (3) corresponding to a level of a broad band signal before passing through a BPF (11) and controlling a gain of an IF amplifier (12) corresponding to a level of a narrow band signal after passing through the BPF (11), moreover, it is possible to properly control a gain of an AGC as a whole in consideration of signal levels of both a desirable wave and a disturbing wave.

Abstract: An integrated circuit chip include a transmitter configured for transmitting an electromagnetic signal, a receiver configured for receiving an electromagnetic signal, and an amplifier operatively coupled to the receiver. The amplifier includes a plurality of variable-gain Gm-C filter stages connected in series and configured for selectively amplifying frequency components within a frequency bandwidth of the received electromagnetic signal.

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: 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 high-frequency receiver capable of improving both an interference-resistant characteristic and reception sensitivity is provided. A gain switch control unit includes: a signal level determination unit comparing a gain control voltage of an amplifying circuit with a reference voltage; and a gain switch controller provided between an output terminal of the signal level determination unit and a gain control input terminal provided to an amplifying circuit for gain control. When receiving a signal in a strong electric field area having a high possibility that a strong interference signal exists, a gain of the amplifying circuit is set to be smaller than that in a case of receiving a signal in a weak electric field area by a gain switch signal output from the gain switch controller.

Abstract: Multi-segment gain control system. Apparatus is provided for a multi-segment gain control. The apparatus includes logic to convert a gain control signal to an exponential signal, and logic to map the exponential signal to multiple control signals that are used to control multiple gain stages to produce linear multi-segment gain control.

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: A comparison is made in a number of scenarios of a current channel gain setting for a receiver to a threshold. If the current channel gain setting is less than the threshold, then current within at least a portion of the receiver is decreased. In one scenario, the comparison is only made in event that no single tone interferer is detected. In another scenario, the comparison is made to a tolerable single tone blocker threshold, and if greater then current is decreased. In another scenario, the comparison is made to an acceptable intermodulation response rejection threshold, and if greater then current is decreased. In yet another scenario, the comparison is made to an acceptable spurious free dynamic range threshold, and if greater then current is decreased. The portions of the receiver for which current decreases are implemented include a low noise amplifier, mixer, voltage controlled oscillator and variable gain amplifiers.

Abstract: A monolithic radio integrated circuit includes a substrate, a set of one or more analog subcircuits on the substrate, a programmable bias current supply on the substrate coupled to the set to provide bias currents to the analog subcircuits of the set including programmable bias currents to one or more analog subcircuits forming a first subset of the set, and a digital subsection coupled to the programmable bias supply to determine the bias currents supplied to the analog subcircuits of the first subset, such that one or more characteristics of the radio integrated circuit are modifiable by programming the programmable bias supply.

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: An integrated tuner is programmable to optimize its components for either analog signal reception or digital signal reception. Power to the components is increased for analog operation and decreased for digital operation. The tuner also includes a selectable and integrated low noise amplifier that may be selected for single-signal reception and bypassed for multi-signal reception.

Abstract: A method and apparatus are provided to generate calibration signals to multiple stages in a receiver channel. The multiple stages are calibrated using multiple calibration circuits, where a controller controls each calibration circuit. The controller is coupled to the output of the final stage in the receiver channel through a single comparison unit. The output from the single comparison unit is used by the controller to calibrate each of the multiple stages.

Abstract: A radio receiver is selectively operable in a current mode or a voltage mode according to conditions prevailing within a wireless environment. If the signal levels within the wireless environment are relatively low, the radio receiver is operable in current mode. If the signal levels within the wireless environment are relatively high, the radio receiver is operable in voltage mode. The radio receiver is switchable between current and voltage mode of operation via selectively actuable switches that bringing into effect or remove from effect corresponding resistances.

Abstract: A call apparatus, a call method and a call system, are disclosed, in which the problem otherwise caused by fixed setting of the sound volume level of the BGM or the effect sound with respect to the call voice may be overcome. A decoded output of a decoder 17 (PCM data) is multiplied in a gain adjustment unit 18 with a gain coefficient k2, as the SE sound volume level as set by a user. A multiplication output of the gain adjustment unit 18 is sent to an adder 13. The decoded output of a decoder 20 is multiplied in a gain adjustment unit 21 with a gain coefficient k3, as the BGM sound volume level, as set by the user. A multiplication output of the gain adjustment unit 21 is sent to an adder 13. The adder 13 sums the multiplication outputs of the gain adjustment units 12, 18 and 21 and sends a sum output to an encoder 22.

Abstract: An automatic gain control (AGC) technique can quickly sense signal size over a large dynamic range by using a peak detector block in the analog portion of the receiver. The peak detector block can compare a received signal to predetermined thresholds (chosen to divide a potential signal range into smaller ranges). Therefore, the peak detector block can assist the automatic gain control (AGC) in quickly sizing the received signal. The AGC technique can also reduce digital filter settling time by simulating a gain change and providing this simulated value to the digital filters of the receiver. DC or spur components can be estimated prior to and after performing an analog gain change and then removed from digital signal samples. The digital signal samples sampled prior to performing the analog gain change can then be rescaled and provided to the digital filter, thereby avoiding discontinuity in a digital signal.

Abstract: An analog baseband circuit includes first and second DC (direct current) offset cancellers and an offset canceller controller. The first DC offset canceller includes a first filter and a first PGA (programmable gain amplifier) with a first gain step for eliminating a first dc component from an input baseband signal. The second DC offset canceller includes a second filter and a second PGA with a second gain step less than the first gain step for eliminating a second dc component from an output of the first DC offset canceller. The offset canceller controller controls the first and second filters to operate in a fast mode when a gain of the first PGA is changed.

Abstract: Systems and methods are provided for reducing the peak to average ratio of signals, so that the signals can be amplified more efficiently. An error signal that corresponds to crests of the input signal is generated, and subtracted from the input signal. When a crest is so long that it corresponds to more than one sample, only the maximum sample contained in the crest is used to form the error signal. Optionally, multiple stages of decresting may be implemented sequentially.

Abstract: An AM receiver incorporates an antenna, a transistor, a current source, and a power supply. The antenna is connected to a gate electrode of the transistor and through a link to a signal earth. In operation, the antenna receives radiation and generates a corresponding input signal which propagates to the gate electrode. The transistor is operable to process the input signal in two steps, namely to reflectively amplify the input signal to generate a correspondingly reflectively amplified input signal at the gate electrode in a first step, and amplitude demodulate the amplified input signal in a second step. The transistor is operable in a non-linear region of its current/voltage characteristic whereas it simultaneously provides reflective amplification and signal demodulation, namely the two steps occur simultaneously.

Abstract: A base band circuit of a receiver and a low cut-off frequency control means can quickly converge transition state due to gain fluctuation with setting a low cut-off frequency of a high-pass filter as low as possible. The base band circuit of a receiver has a variable amplifier variably amplifying a base band signal depending upon a gain control signal, a high-pass filter provided in a path of the base band signal, and a controller detecting variation magnitude of the gain control signal and controlling variation of a low cut-off frequency of the high-pass filter means depending upon the detected variation magnitude.

Abstract: A receiving circuit of a direct conversion system is provided which includes a differential amplifier circuit which amplifies a received signal, a mixer which combines the amplified received signal and an oscillation signal having a predetermined frequency to thereby perform frequency conversion, and a high gain amplifier circuit in which a plurality of programmable gain amplifiers and a plurality of filters which eliminate noise of the received signal and an unnecessary wave, are connected in a multistage and which is configured such that an amplification factor is varied according to the level of the received signal. In the receiving circuit, the low noise amplifier is brought to a non-operating state to thereby allow execution of a DC offset cancel operation of the corresponding programmable gain amplifier on the pre-stage side of the high gain amplifier circuit.

Abstract: The receiver is provided which comprises a mixer, a low pass filter coupled to the mixer and a plurality of gain controllers serially coupled to an output of the low pass filter (LPF). A plurality of analog-to-digital converters (ADCs) is coupled so that an input of a first of the ADCs is coupled to the output of the LPF. An input of each of a remaining portion of the ADCs is individually coupled to a corresponding output of each of the serially coupled gain blocks. An output path traced from the output of the LPF to an output of each of the analog-to-digital converters may be referred to as a processing path. Each processing path may comprise a gain controller and an ADC, except for the first processing path, which may have an ADC coupled directly to the output of the LPF.

Abstract: A radio receiver comprises a first amplifier to amplify a received radio signal; a quadrature demodulator to demodulate the radio signal amplified by said first amplifier and thereby generate a baseband signal; a second amplifier to amplify the baseband signal; a demodulator to demodulate the baseband signal amplified by said second amplifier; and a gain controller to control timing of a change in a gain of said second amplifier, in case that changing the gain of said first amplifier and the gain of said second amplifier, on the basis of a gain of said first amplifier before and after the change.

Abstract: Disclosed is a variable gain control circuit for executing automatic-gain-control on a variable gain amplification block composed of a plurality of amplifiers on which discrete gain setting is executed by a programmable-gain-amp method. A baseband amplifier (a variable gain amplifier) is composed of a plurality of amplifiers on which discrete gain setting is executed by a programmable-gain-amp method. A programmable-gain-amp control processing block references a programmable-gain-amp control data table on the basis of a difference between a current receive signal level and a predetermined receive signal level to determine the gain of the baseband amplifier, thereby making a programmable-gain-amp data generator generate programmable-gain-amp data.

Abstract: An RF receiver comprising a radio-frequency (RF) down-converter for receiving and down-converting an input RF signal to a lower frequency analog signal (e.g., an IF signal or baseband signal) and analog processing circuitry for receiving the lower frequency analog signal from the RF down-converter and outputting a processed analog signal. The processed analog signal includes a DC-offset signal introduced by the RF down-converter and the analog processing circuitry. The RF receiver also comprises an ADC circuit for converting the processed analog signal to a sequence of digital samples and a DC-offset correction circuit for detecting the DC-offset signal in a digital output signal of the RF receiver. The DC-offset correction circuit adds a DC-offset correction signal to the lower frequency analog signal. Adding the DC-offset correction signal to the lower frequency analog signal reduces the DC-offset signal in the processed analog signal at the analog processing circuitry output.

Abstract: There are provided, as a low noise amplifier (70) a low noise amplifier (71) with a low gain and a low noise amplifier (72) with a high gain, selectively operable under control of a bias current, and an output from the low noise amplifier (72) and a quadrature demodulator (80) are connected with a serial capacitance (73) and also an output from the low noise amplifier (71) and the quadrature demodulator (80) are serially connected. A control section (66) controls a reception circuit so that the low noise amplifier (71) operates when a reception signal level is high and the low noise amplifier (72) operates when the reception signal level is low. When the low noise amplifier (72) operates, a DC bias current thereof is made flow separately from a DC bias current of the quadrature demodulator (80), and, when the low noise amplifier (71) operates, a DC bias current thereof is shared with the quadrature demodulator.

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 wireless communication receiver that is able to lessen the effect of noise that accompanies gain change by programmable gain amplifiers. The receiver includes an AGC controller which controls the timing at which the programmable gain amplifiers make gain change, using a terminal counter and a sequencer. The receiver prevents gain change noise signals during the reception of control signals and other signals that are susceptible to noise. By the timing control feature, the programmable gain amplifiers make gain change while reducing noise impact.

Abstract: An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

Abstract: A circuit is formed to steer current in and out of an inductive load in a manner that enables an amplifier to provide a plurality of gain steps without modifying an LC time constant for the circuit and, therefore, without modifying the tuning or frequency of oscillation for the circuit. A first group of MOSFETs are coupled in parallel and define the circuit current flow. A second group of MOSFETs are coupled in parallel to each other and in series to an impedance device. A third group of MOSFETs coupled to steer current in and out of the impedance device to affect the output signal coupled to one end of the impedance device. The transistors in the second and third groups of MOSFETs are selectively activated to control the amount of current that goes through the impedance device.

Abstract: Disclosed herein is a direct conversion type signal processing semiconductor integrated circuit device capable of suppressing a DC voltage variation in the output of a variable gain amplifier upon the transition to a reception mode, reproducing stable receiving characteristics and improving receiving sensitivity. In the signal processing semiconductor integrated circuit device, voltage reference circuits for generating reference voltages for controlling or restricting currents for current sources for supplying operating currents for amplifiers constituting a reception-system circuit are boosted upon the transition from an idle mode or the like to the reception mode to allow the currents to flow into the constant-current sources of the amplifiers after the stabilization of the generated reference voltages.

Abstract: A method and device are disclosed for receiving digital television signals by a frequency tuner. The power of the signal is measured after an analog/digital conversion in the frequency tuner, and the gain thereof is controlled on the basis of this power measurement according to a predetermined control law. The power of the analog signal, tapped between an input amplifier stage and a first frequency transposition stage, or immediately after the first frequency transposition stage, is also measured. The measured power is compared with a predetermined power threshold so as to obtain first binary information, and the gain control law is set on the basis of the value of the first binary information.

Abstract: Automatic gain control (AGC) methods and apparatus suitable for use in orthogonal frequency division multiplexing (OFDM) receivers are described. One AGC method includes the steps of repeatedly performing a first AGC process which adjusts amplifier gain based on determining that a signal level of multiple time sample values is outside a limit set by a first predefined threshold; and repeatedly performing a second AGC process which adjusts the amplifier gain based on determining that a signal level of multiple frequency sample values associated with a plurality of pilot tones is outside a limit set by a second predefined threshold. Preferably, the first AGC process is performed repeatedly at a first rate and the second AGC process is performed repeatedly at a second rate that is less than the first rate.

Abstract: A high-speed digital received signal strength indicator (RSSI) circuit is provided.

Abstract: A first AGC voltage and a second AGC voltage are taken from the final stage of a radio-frequency circuit and the output side of a bandpass filter, respectively, and the gain of the radio-frequency circuit is controlled on the basis of the two AGC voltages. The pass-band width of the bandpass filter is approximately two times greater than the frequency interval of FM broadcast signals. The second AGC voltage is set higher than the first AGC voltage in the pass-band of the bandpass filter.

Abstract: Techniques to reduce LO leakage by controlling the amplitude of LO signal based on the level of output signal after the frequency conversion process. An LO generator receives a VCO signal and generates an LO signal having a variable amplitude and a frequency that is related to the frequency of the VCO signal. A variable gain amplifier receives a control signal and adjusts the amplitude of the LO signal based on the control signal. The variable amplitude LO signal is used for frequency upconversion (e.g., direction upconversion) of an input signal (e.g., at baseband) to obtain an output signal (e.g., at RF). The relationship between LO signal amplitude and output signal level may be defined by a particular transfer function. In general, the LO signal is set higher for higher output signal level and is reduced proportionally for lower output signal level.

Abstract: A multi-stage amplifier is coupled with a power detector. The multi-stage amplifier includes a plurality of amplifier stages in series, with a signal path extending through them. The power detector is coupled to an interior node of the amplifier along the signal path, and is operable to sample a first signal being transmitted on the signal path. The power detector outputs a second signal reflective of a power of the first signal. In one embodiment, the interior node is in a matching network of the amplifier disposed between a first amplifier stage and a final amplifier stage of the amplifier. The second signal may be used in a feedback network to adjust an amount of amplification of the first signal by the amplifier.

Abstract: Methods and circuits for reducing power dissipation in wireless transceivers and other electronic circuits and systems. Embodiments of the present invention use bias current reduction, impedance scaling, and gain changes either separately or in combination to reduce power dissipation. For example, bias currents are reduced in response to a need for reduced signal handling capability, impedances are scaled thus reducing required drive and other bias currents in response to a strong received signal, or gain is increased and impedances are scaled in response to a low received signal in the presence of no or weak interfering signals.

Abstract: An exemplary embodiment of the present invention described and shown in the specification and drawings is a transceiver with a receiver, a transmitter, a local oscillator (LO) generator, a controller, and a self-testing unit. All of these components can be packaged for integration into a single IC including components such as filters and inductors. The controller for adaptive programming and calibration of the receiver, transmitter and LO generator. The self-testing unit generates is used to determine the gain, frequency characteristics, selectivity, noise floor, and distortion behavior of the receiver, transmitter and LO generator. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

Abstract: A method for measuring a difference in DC offsets associated with different gain settings in a direct conversion receiver having a variable gain is provided. In a first phase, a set of response parameters that characterize a time-dependent system response to a known change in the DC offset is determined. Each response parameter corresponds to the response measured at a different time after the change. In a second phase, different gain settings are applied to the system and the response is measured at times corresponding to the times associated with each of the response parameters. The response parameters are then used to determine the difference in DC offsets associated with the different gain settings.

Abstract: A direct conversion receiver comprises a low noise amplifier, a bandpass filter, a mixer circuit and a baseband processing assembly. The low noise amplifier is capable of receiving communication signals from an antenna and, in turn, the bandpass filter is capable of filtering the received signals to a bandpass including a reception frequency band. The mixer circuit is electrically connected to an output of the bandpass filter, and can demodulate the received signals into differential signals in two channels. The baseband processing assembly is electrically connected to the mixer circuit opposite said bandpass filter. In this regard, the baseband processing assembly can process the demodulated differential signals in at least one of the channels. And to compensate DC offset from the demodulated differential signals, for each channel the baseband processing assembly includes a pair of dynamic offset compensation elements and a static offset compensation element.

Abstract: A high frequency circuit capable of realizing a power amplifier with a wide dynamic range in which it is hard to degrade the power addition efficiency at low output is formed by using a high output amplifier cell block configured to amplify input signals at a time of high output power, in which a DC power source voltage is supplied in parallel to first amplifier cells that are connected in parallel AC-wise with respect to input/output signals, and a low output amplifier cell block configured to amplify input signals at a time of low output power, in which a DC power source voltage is supplied in series to second amplifier cells that are connected in parallel AC-wise with respect to input/output signals.

Abstract: A receiver generates two metrics, one that is used to control the gain of an amplifier and the other that is used to determine the presence of narrowband interference, such as IMD. The two metrics may represent analog-to-digital converter (A/D) saturation and average signal strength, either of which may be used to control gain or to detect the presence of narrowband interference.

Abstract: A control interface scheme provides for communicating control information between integrated circuits (ICs) in a wireless communication chipset. A serial 3-wire bus is configured to communicate a series of control words assembled on a digital IC to an analog IC prior to a data portion of a frame used by the wireless communication chipset in communicating data. The control words include control settings for use by the analog IC during the data portion of the frame. The control settings, which are stored in registers on the analog IC, include gain settings for two receivers and a transmitter, as well as phase lock loop (PLL) control information and power management information. Several timing signals generated on the digital IC are used by the analog IC during the data portion of the frame to select among the registers to obtain the appropriate control settings at the appropriate times.

Abstract: Techniques for improved low latency frequency switching are disclosed. In one embodiment, a controller receives a frequency switch command and generates a frequency switch signal at a time determined in accordance with a system timer. In another embodiment, gain calibration is initiated subsequent to the frequency switch signal delayed by the expected frequency synthesizer settling time. In yet another embodiment, DC cancellation control and gain control are iterated to perform gain calibration, with signaling to control the iterations without need for processor intervention. Various other embodiments are also presented. Aspects of the embodiments disclosed may yield the benefit of reducing latency during frequency switching, allowing for increased measurements at alternate frequencies, reduced time spent on alternate frequencies, and the capacity and throughput improvements that follow from minimization of disruption of an active communication session and improved neighbor selection.

Abstract: A low-noise amplifier for a mobile communication terminal maintains linearity with the least current consumption. A low-noise amplifier controller detects a signal-to-noise ratio (SNR) of a received signal, and outputs a control signal of a preset voltage when the SNR is lower than a predetermined SNR even though AGC AMP controller increases the AGC gain according to field strength. A bias circuit increases a bias current according to the control signal output from the low-noise amplifier controller. A low-noise amplifier amplifies the received signal to a preset level according to the bias current provided from the bias circuit.

Abstract: A rapid acquisition gain control system for use in a wireless communication device having an RF input and a receive signal path including RF and baseband portions. The system includes two or more dual-state gain elements, two or more power detectors and control logic. The gain elements are sequentially coupled in the receive signal path of the wireless device and collectively have multiple combined gain states. Each combined gain state corresponds to one of several gain range segments of a predetermined dynamic range. Each power detector is coupled to detect an output power level associated with one of the gain elements. The control logic changes the combined gain state of the gain elements if a change of power level of energy processed in the receive signal path exceeds a predetermined threshold and a different combined gain state is indicated by the power detectors.

Abstract: Automatic gain control (AGC) methods and apparatus suitable for use in orthogonal frequency division multiplexing (OFDM) receivers are described. One AGC method includes the steps of repeatedly performing a first AGC process which adjusts amplifier gain based on determining that a signal level of multiple time sample values is outside a limit set by a first predefined threshold; and repeatedly performing a second AGC process which adjusts the amplifier gain based on determining that a signal level of multiple frequency sample values associated with a plurality of pilot tones is outside a limit set by a second predefined threshold. Preferably, the first AGC process is performed repeatedly at a first rate and the second AGC process is performed repeatedly at a second rate that is less than the first rate.

Abstract: A satellite radio is configured to receive a digital broadcast signal from a satellite, and to prevent abrupt changes in sound volume level that startle the driver and accompanying passengers from occurring. The satellite radio preferably has a microcomputer with a reception determining section and a sound volume controlling section. The reception determining section determines the strength (e.g., receivable or not receivable) of the broadcast signal. The sound volume controlling section controls the sound volume level in response to the strength of the broadcast signal. The sound volume controlling section mutes or reduces the sound volume level when the broadcast signal is below a first predetermined reception level. Thereafter the sound volume controlling section gradually increases the sound volume level when the strength of the broadcast signal has changed from the first predetermined reception level to a second predetermined reception level.

Abstract: A receiver having a digital automatic gain control (AGC) circuit is disclosed for use in a cellular communication system, including a Hierarchical Cellular System. The receiver includes a controller which switches between gain control values depending on system operational mode. In this way, the AGC can be optimized for different types of receive processing operations, e.g., traffic reception and measurement of other channels.