Abstract: A method and circuitry for a receiver are disclosed. In the method a signal is received in a signal processing path of the receiver. Direct voltage that is present in the received signal is reduced by compensation means (12). The amplitude of the signal is attenuated by frequency selective attenuation means (10) during the direct voltage reduction by the compensation means (12).

Abstract: A hearing compensation system for the hearing impaired comprises a plurality of bandpass filters having an input connected to an input transducer and each bandpass filter having an output connected to the input of one of a plurality of multiplicative AGC circuits whose outputs are summed together and connected to the input of an output transducer. The multiplicative AGC circuits attenuate acoustic signals having a constant background level without the loss of speech intelligibility. The identification of the background noise portion of the acoustic signal is made by the constancy of the envelope of the input signal in each of the several frequency bands. The background noise that will be suppressed includes multi-talker speech babble, fan noise, feedback whistle, florescent light hum, and white noise.

Abstract: A power measurement element (106) measures (302) the wide-band received signal power of a receiver (102), and a wide-band AGC system (108) transfers (306) receiver gain control from an on-channel AGC system (110) to the wide-band AGC system, when the wide-band received signal power exceeds a pre-programmed threshold for longer than a pre-programmed delay time. The wide-band AGC system is arranged and programmed to decrease (308) a front-end gain of the receiver through a plurality of gain steps of a pre-programmed size (208) applied at a pre-programmed rate until the received wide-band signal power falls below the pre-programmed threshold.

Abstract: An integrated receiver with channel selection and image rejection substantially implemented on a single CMOS integrated circuit is described. A receiver front end provides programmable attenuation and a programmable gain low noise amplifier. Frequency conversion circuitry advantageously uses LC filters integrated onto the substrate in conjunction with image reject mixers to provide sufficient image frequency rejection. Filter tuning and inductor Q compensation over temperature are performed on chip. The filters utilize multi track spiral inductors. The filters are tuned using local oscillators to tune a substitute filter, and frequency scaling during filter component values to those of the filter being tuned. In conjunction with filtering, frequency planning provides additional image rejection. The advantageous choice of local oscillator signal generation methods on chip is by PLL out of band local oscillation and by direct synthesis for in band local oscillator.

Abstract: A gain control circuit comprises a variable gain circuit having a predetermined gain control range and a control voltage supply circuit for supplying an internal control voltage to the variable gain circuit as a gain control signal. In this gain control circuit, the control voltage supply circuit generates the internal control voltage in response to an external control voltage so as to compensate the linearity of the variable gain circuit to the extent of the external control voltage where the variable gain circuit loses linearity. This gain control circuit is applied to an AGC circuit of the transmitting stage in a CDMA-type mobile phone.

Abstract: In a time-division duplex (TDD) system, a reliable initialization scheme that is applicable to an automatic gain controller (AGC) at a base station is implemented in various forms depending on the availability of certain information such as signal-to-interference ratio (SIR), spreading factors and other parameters. A more accurate estimation of the initial control word of a gain-adjustable amplifier for one or more time slots is implemented. The scheme is applicable to AGC initialization for each time slot of the TDD system, but is also applicable to other systems of transmission, without limitation.

Abstract: An integrated circuit superheterodyne radio receiver includes a notch filter coupled with an amplifier for amplifying radio frequency (RF) signals to improve image signal rejection. The notch filter includes a first oscillator circuit with a tank circuit having a resonant frequency corresponding to the unwanted image frequency signal. A control circuit includes a second oscillator circuit, a master bias circuit and a slave bias circuit. The second oscillator circuit is substantially similar to the first oscillator circuit. The master bias circuit is responsive to an amplitude of oscillatory signals in the second oscillator circuit for limiting a flow operating current such that the second oscillator circuit is restrained to operate in a marginally oscillatory state. A slave bias circuit is responsive to the master bias circuit for similarly limiting a flow of current, for operating the first oscillator circuit.

Abstract: A Radio Frequency (RF) receiver includes a low noise amplifier (LNA) and a mixer coupled to the output of the LNA. The gain of the LNA is adjusted to maximize signal-to-noise ratio of the mixer and to force the mixer to operate well within its linear region when an intermodulation interference component is present. The RF receiver includes a first received signal strength indicator (RSSI_A) coupled to the output of the mixer that measures the strength of the wideband signal at that point. A second received signal strength indicator (RSSI_B) couples after the BPF and measures the strength of the narrowband signal. The LNA gain is set based upon these signal strengths. LNA gain is determined during a guard period preceding an intended time slot of a current frame and during a guard period following an intended time slot of a prior frame. The lesser of these two LNA gains is used for the intended time slot of the current frame.

Abstract: A wireless communication apparatus according to the present invention is composed of a first section for carrying out wireless communication with a multichannel signal and a second section having a plurality of channel units each process a predetermined frequency signal as a channel signal. The wireless communication apparatus is arranged to have a plurality of variable attenuators each provided for corresponding one of the channel signals received from each channel unit of the second section, a combiner for combining outputs from the respective variable attenuators together and outputting the resultant combined signal to the first section, and a control unit for controlling the degree of attenuation of the individual variable attenuators according to the variation of the number of the channel signals.

Abstract: A method and apparatus for dynamically controlling a programmable gain amplifier (PGA) to provide a plurality of gain steps thereby providing automatic gain control (AGC) in a receiver intermediate frequency (IF) stage comprising a succession of operational amplifiers wherein at least one is for providing fine gain control and wherein the gain of each fine gain amplifier is controlled by the resistance ratios of a plurality of selectively biased MOSFETs. In one embodiment of the invention, three coarse amplifiers are provided, each having a gain of either 0 dB or 12 dB based on the value of a two-state signal provided to each amplifier gain control input. A single fine gain amplifier has a gain of 0 dB, 3 dB, 6 dB or 9 dB based on the binary value of the two-bit signal provided to the amplifier. The combination of three coarse gain amplifiers and one fine gain amplifier provides for a total gain of 45 dB in 3 dB steps in the described embodiment of the invention.

Abstract: A system adjusts a receiving device in response to sensing symbols. An automatic gain control is adjusted in response receiving a first symbol of a data unit from a first antenna. After adjusting the automatic gain control at least a second and a third symbol of the data unit are received, and in response thereto (1) a first energy of at least one of the second and third symbols is calculated, (2) a first frequency offset of at least one of the second and third symbols is calculated, and (3) a first temporal offset of at least one of the second and third symbols is calculated. The automatic gain control in response receiving a fourth symbol of the data unit from a second antenna is received.

Abstract: An antenna weight estimation method in a mobile communication system is capable of improving the accuracy of antenna weight estimation values, thereby improving communication quality and increasing radio channel capacity. It operates instantaneous estimation and accumulative estimation in parallel, in which the former is made for estimating the antenna weight used for received SNIR estimation for transmission power control, and the latter is made for demodulating the received data. Thus, it can obtain the antenna weight for the received SNIR measurement with a minimum delay, and at the same time, it can improve the reliability of the antenna weight for the data demodulation.

Abstract: A modulator receives an I-phase transmission data signal and a Q-phase transmission data signal, which have been spread-spectrum processed, and modulates an intermediate frequency signal in accordance with the data signals, an IF-AGC amplifier amplifies the output of the modulator, the gain of the IF-AGC amplifier being controlled in accordance with a gain control signal, an up-converter increases the output of the IF-AGC amplifier to a propagation frequency, the gain of the up-converter being controlled in accordance with a control signal.

Abstract: A receiver portion of a radio includes an analog circuit for determining a peak amplitude in a way that eliminates or reduces the effects of frequency errors that are introduced by crystals within filters and other devices. A voltage follower and a current mirror in which a MOSFET coupled to an output node produces a voltage across its gate to source terminals whose value is a function of a sum of the gate to source voltages of two MOSFET devices that receive a logarithm of an I modulated channel and a logarithm of a Q modulated channel, respectively.

Abstract: An automatic gain control (AGC) circuit has an automatic gain controlled amplifier connected in series with a DC blocking capacitor. A reference DC voltage is selectively applied to an input of the automatic gain controlled amplifier and to an output of the DC blocking capacitor output so as to cause the DC blocking capacitor to store a charge proportional to a DC voltage offset introduced by the controllable gain amplifier. The selectively application of the reference DC voltage is momentarily applied for a duration of less than about 1 microsecond and preferably about 0.4 microseconds. The AGC circuit, including both the amplifier and capacitor, are fabricated as an integrated circuit device.

Abstract: A method of providing an automatic gain control (AGC) in a receiver structure includes multiplying a received analogue signal with a predetermined gain setting to obtain an amplifier output signal, sampling the amplifier output signal, estimating the energy in the samples, calculating the average energy, computing the percentage of clipped samples, calculating the target energy value based on the average energy and the percentage of clipped samples and the gain setting, and applying the update receiver gain setting.

Abstract: A data portion measuring section 103 measures a reception level of a data portion of a received signal, and a pilot portion measuring section 104 measures a reception level of a pilot portion of the received signal. A comparing/selecting section 105 compares the reception level of the data portion with that of the pilot portion, and selects a higher reception level. An AGC gain value calculating section 106 calculates an AGC gain value from the higher reception level selected by the comparing/selecting section 105 and an input allowable level of A/D conversion.

Abstract: A receiving circuit includes a converter 1 of which gain is switched such that the gain is decreased through a plurality of stages in response to an increase in the intensity of the received signal, for converting the received signal into an intermediate frequency signal, and a base band processing circuit 5 for switching the gain of the converter 1. The gain of the converter 1 is switched to the lower level at the output level of the converter 1 corresponding to the minimum level of the received signal input into converter 1 at which an allowable error rate is secured in the base band processing circuit 5 at the maximum gain. When the converter 1 is set up to the maximum gain mode, the level of the intermediate frequency signal is lowered by attenuation means ATT provided in the converter 1.

Abstract: The invention provides a radio circuit realizing a desired receiving characteristic even when a strong-level interfering wave is received and operating with small power when no interfering wave is received. The radio circuit comprises a receiving circuit for selecting a signal having a desired frequency from received signals and demodulating the signal, an input-power detector for detecting power P1 of the receiving circuit, a received-power detector for detecting power P2 of a signal selected by the receiving circuit, and a reception control circuit for controlling the receiving circuit. The reception control circuit controls the receiving circuit at a low distortion by increasing the power consumption of a circuit included in the receiving circuit and thereby expanding the linear operation range when the power P1 detected by the input-power detector is larger than a predetermined value t1 and the power P2 detected by the input-power detector is smaller than a predetermined value t3.

Abstract: Conventional digital broadcast receiving tuners normally perform identical operations regardless of whether the actual level of a signal received within a receivable frequency band remains flat or irregular, and this makes it impossible to obtain optimal performance characteristics according to the level of the received signal.

Abstract: In accordance with an embodiment of the present invention, a dynamics processor includes a non-linear automatic gain control (AGC) responsive to an input audio signal comprised of a plurality of frequency components, each frequency component having associated therewith an amplitude, said non-linear AGC adaptive to develop a modified gain audio signal. A multiband cross-over device is responsive to the modified gain audio signal and is adaptive to generate ‘n’ number of signals, each of said ‘n’ signals having an amplitude and further having a unique frequency band associated therewith.

Abstract: An object of the invention is to receive a weak signal with high sensitivity and reduce distortion and signal suppression when a strong interference signal exists. When a high-frequency signal received by an antenna is to be amplified by an antenna amplifier and when an interference wave of high field strength exists, a switch circuit is switched by an output switchover circuit from the output of an amplifier to a through-circuit. The through-circuit guides the high-frequency signal, directly to the output side without passing through the amplifier. When the switching operation of the switch circuit is performed based on low-frequency components which are highly correlated with distortion components due to intermodulation, the switching operation can be performed more adequately. Noises can be reduced by performing a smoothing process on the switching operation, and the use of an inverting amplifier can prevent occurrence of oscillation.

Abstract: In accordance with embodiments of the present invention, a receiver system is provided with a variable gain mixer circuit that is advantageous over current architectures used in wireless communication systems. The use of a variable gain mixer circuit simplifies the receiver architecture resulting in the elimination of additional circuit blocks and a reduction in complexity and cost. Moreover, one embodiment of the present invention includes a mixer circuit comprising a mixer core, a bias circuit coupled to the mixer core for providing a bias current, and a variable impedance network. The mixer core receives input signals and generates output currents that are coupled to the variable impedance network. Each of the output currents are selectively coupled to a voltage output node through a variable impedance. Variable gain is established by varying the impedance between the output currents of the mixer core and the voltage output node.

Abstract: A transceiver includes a switching unit configurable for isolating an input of a receiver from an output of a transmitter during a local calibration mode. A known signal present at the output at a first power level during the calibration mode will also be present at the input at a second power level lower than the first power level and will be converted by the quadrature demodulator. A compensation factor is estimated for compensating the receiver section for imbalances in the in-phase and quadrature phase signals resulting from conversion of the known signal. Remote calibration is implemented using a method for remotely compensating for I−Q imbalance wherein a data packet having a known signal is transmitted to a receiver for conversion by a quadrature demodulator and compensation factors are estimated for compensating for imbalances in the in-phase and quadrature phase signals resulting from conversion of the known signal.

Abstract: A tuning circuit having an amplitude-varying function is disclosed that comprises a coil, a capacitor, and a resistance-adjusting element connected in parallel to the coil and the capacitor for varying resistance at time of resonance of the tuning circuit, wherein the amplitude of an output signal of the tuning circuit is varied by varying the resistance with the resistance-adjusting element.

Abstract: An aspect of the present invention provides a receiving circuit that includes a mixer configured to receive a signal and a local signal to mix the signals, the mixer configured to convert the signals into an intermediate frequency signal, an IF filter configured to filter the intermediate frequency signal outputted from the mixer, an IF amplifier configured to amplify a band of the intermediate frequency signal outputted from the IF filter, and a demodulation circuit configured to receive a signal outputted from the IF amplifier to carry out demodulation, wherein a part of the demodulation circuit is disposed outside of the receiving circuit.

Abstract: A high frequency part, which amplifies a high frequency signal outputted from an intermediate frequency part and supplies to an antenna, is equipped with a gain controller with switch function. The gain controller with switch function comprises an attenuator with switch function has a function of switching a selected band between two bands outputted from the intermediate frequency part and controlling the gain of the high frequency signal in the selected band. The attenuator with switch function comprises a first variable resistor which connects a signal input part with a signal output part and a second variable resistor which is disposed parallel to said first variable resistor and connects a signal input part with a signal output part. The first and the second variable resistors are controlled by a common gain control voltage and set such that the gain control voltage ranges, which are for changing the resistor values, will not overlap with each other.

Abstract: A wireless communication apparatus according to the present invention is composed of a first section for carrying out wireless communication with a multichannel signal and a second section having a plurality of channel units each process a predetermined frequency signal as a channel signal. The wireless communication apparatus is arranged to have a plurality of variable attenuators each provided for corresponding one of the channel signals received from each channel unit of the second section, a combiner for combining outputs from the respective variable attenuators together and outputting the resultant combined signal to the first section, and a control unit for controlling the degree of attenuation of the individual variable attenuators according to the variation of the number of the channel signals.

Abstract: An apparatus and method for comparing the amplitudes of two electric signals Iout and Qout are disclosed. The method includes a step wherein powers conveyed by the signals Iout and Qout are compared. One feature of the method and apparatus is that it is not necessary to storing the maxima of the signals to be compared when these signals are out of phase with respect to each other. One application of the method or apparatus is for the correction of differences in amplitude between I, Q signals that are separated in phase by 90° inside QAM, QPSK or QBSK demodulators.

Abstract: A communication module includes a variable gain amplifier, a mixer stage responsive to the variable gain amplifier, a post-mixer amplifier stage responsive to the mixer stage, and an off-channel signal detector responsive to the post-mixer amplifier stage. The post-mixer amplifier stage is to produce a first differential signal and a second differential signal. The off-channel signal detector has a first input to receive the first differential signal and has a second input to receive the second differential signal. The off-channel signal detector includes a programmable hysteresis comparator module, and the off-channel signal detector has an output to produce an output signal that indicates whether an off-channel signal condition is detected.

Abstract: A device for ensuring that the amplitude of signals fall within a predetermined range, said device comprising input means for receiving a plurality of input signals at substantially the same time, a first path for increasing the amplitude of any of the input signals having an amplitude below a first threshold, a second path for decreasing the amplitude of any of the input signals having an amplitude which exceeds a second threshold and combining the outputs of the first and second paths to provide a plurality of signals having amplitudes between said first and second thresholds.

Abstract: An embodiment of the present invention provides an automatic gain control system for a wireless receiver that quickly differentiates desired in-band signals from high power out-of-band signals that overlap into the target band. The system measures power before and after passing a received signal through a pair of finite impulse response filters that largely restrict the signal's power to that which is in-band. By comparing the in-band energy of the received signal after filtering to the total signal energy prior to filtering, it is possible to determine whether a new in-band signal has arrived. The presence of this new in-band signal is then verified by a multi-threshold comparison of the normalized self-correlation to verify the presence of a new, desired in-band signal.

Abstract: An interface between an RF processing section and a baseband processing section supports general purpose message transmission as well as satellite positioning system signal sample transmission between the RF processing section and the baseband processing section. The interface includes a bi-directional message interface and a data interface. The message interface supports transmission of power control messages to the RF processing section to provide detailed control over activation or de-activation of individual blocks of hardware circuitry in the RF processing section.

Abstract: In order to compensate for performance degradation caused by inferior low-cost analog radio component tolerances of an analog radio, a future system architecture (FSA) wireless communication transceiver employs numerous digital signal processing (DSP) techniques to compensate for deficiencies of such analog components so that modern specifications may be relaxed. Automatic gain control (AGC) functions are provided in the digital domain, so as to provide enhanced phase and amplitude compensation, as well as many other radio frequency (RF) parameters.

Abstract: Apparatus, and an associated method, for a direct conversion receiver by which to selectably increase the sensitivity of the receiver. The direct conversion receiver includes a baseband amplifier positioned in front of a baseband filter, and coupled to receive a direct-converted baseband signal. The gain at which the baseband amplifier amplifies the signal provided thereto is selected, in combination with gains applied to other amplification elements of the direct conversion receiver to distribute the gain across the receive chain. When a signal received at the receiver includes a large interfering signal component, the gain of the baseband amplifier is reduced to lessen the possibility that the amplified signal become saturated. A gain controller controls the gain of the amplification elements.

Abstract: A novel and useful apparatus for and method of automatic gain control (AGC) using Kalman filtering and hysteresis. A nonlinear, time-variant loop filter such as a Kalman filter is employed in the feedback loop of an AGC circuit. The circuit is able to transition quickly and make fast adaptations to new levels of the input signal by use of a restart mechanism used to dynamically modify the gain of the loop filter thus enabling the AGC circuit to quickly adapt to changes in the signal level of the input. An AGC circuit incorporating a hysteresis circuit in the feedback loop is also disclosed.

Abstract: The invention relates to gain control for an amplifier for received radio signals by means of an automatic gain control signal (c). A down converter (103) produces signal components (I; Q) that are amplified in a respective amplifier (104, 105). Then, the resulting signal components (IP-LP; QP-LP) are digitised in A/D-converters (110; 111) for further processing in a digital signal processor (112) and are also fed to a respective signal level detector (113; 114) whose output signals ([I]; [Q]) are combined (115) into a combined signal (V&Sgr;). This signal (V&Sgr;) is forwarded to a gain control unit (116), which produces the automatic gain control signal (c). The automatic gain control signal (c) controls the gain of the amplifiers (104; 105) such that the resulting signal components (IP-LP; QP-LP) are maintained at signal level ([I]; [Q]) less than a predetermined limit level being adapted to the A/D-converters (110; 111).

Abstract: The present invention is related to a method to provide an automatic gain control (AGC) in a receiver structure, comprising the following steps: multiplying a received analogue signal with a predetermined gain setting to obtain an amplifier output signal, sampling the amplifier output signal, estimating the energy in the samples, calculating the average energy, and the further steps of computing the percentage of clipped samples, calculating the target energy value based on the average energy and the percentage of clipped samples and the gain setting, and applying the updated receiver gain setting.

Abstract: A CMOS low noise amplifier (LNA) is provided that is formed without inductors. The CMOS LNA can be used for a single-chip CMOS RF receiver. The CMOS LNA can include a plurality of amplification stages coupled between an input terminal and an output terminal and a gain controller coupled to each of the plurality of amplifier stages, wherein the CMOS LNA does not include an inductor. Each of the amplification stages can have a symmetrically configured and sized first and second circuits to increase a dynamic range and a feedback loop.

Abstract: An electronic device (1100) includes squaring circuit (1500) that includes a logarithmic compression function (1510), a squaring function (1525), a doubling function (1595), and a logarithmic decompression function (1590). The logarithmic compression function (1510) accepts a binary input (1505) of width W and value X, and produces an output having a binary power component (1520) and a binary magnitude component (1515). The squaring function (1525) generates an adjusted squared magnitude component (1542) and a selection signal (1561). The doubling function (1595) generates a doubled power component (1556). The logarithmic decompression function (1565) generates an approximate squared output (1570) of width 2W from the doubled power and adjusted squared magnitude components (1556, 1542). The approximate squared output (1570) has a value that approximates the square of X to a predetermined amount of precision, N.

Abstract: A front end tuning system includes a tuning signal generator. The tuning signal generator includes a digital-to-analog converter (DAC) to receive a pre-conditioned tuning signal at a reference input, to receive a digital value at a digital control input, and to produce a modified tuning signal based on the digital value and the pre-conditioned signal. Preconditioning the tuning-voltage allows a simple current type DAC to be can be used, rather than an 8-bit ladder type DAC used by some other front end tuners. Significant cost savings can be achieved because less memory is required to store the digital values supplied to the DACs, and set up times can be reduced. An adjustable temperature compensation circuit provides additional adaptability.

Abstract: A digital radio frequency receiver capable of receiving RF signals at a plurality of signal strengths thereby extending the dynamic range of the receiver without introducing a control loop while allowing a stable gain control algorithm to be implemented in software is described. Various embodiments of a digital radio receiver process a range of signals outside normal analog to digital converter capabilities and bypass the delays resulting from gain control loops.

Abstract: An amplifier system having an amplifier for amplifying a communications signal, a scanning receiver for monitoring a signal strength of the communications signal, a microprocessor for determining, based on the signal strength of the communications signal, whether the communications signal should be amplified, and a switch, controlled by the microprocessor, for allowing the communications signal to pass through the amplifier or be terminated.

Abstract: A system and method for controlling amplification of a signal received by a ZIF radio having a power level within a full power range relative to a minimum noise floor. The ZIF radio includes a ZIF receiver front end, an overload detector, an ADC, a saturation detector, a DC and power estimator, and control logic. The control logic utilized full visibility of the ADC to limit gain of the baseband amplifier to a maximum gain setting sufficient to view the minimum noise floor and to view a received signal having a power level within any of several segments of the power spectrum. The segmentation of the power spectrum is based on an overload condition of the ZIF receiver front end and a saturation condition of the ADC. The control logic further employs limited gain stepping of the baseband amplifier to avoid exceeding a DC budget of the ADC.

Abstract: A method for signal gain adjustment in a multi-port, digital distributed antenna system uses a sorter to sort received signals in ascending order according to their signal levels. A threshold comparator generates a dynamic range fair threshold that is updated as any remaining system dynamic range is distributed amongst the remaining signals. Any received signal that is less than or equal to the threshold is attenuated with a unity gain factor. A signal that is greater than the threshold is attenuated with a gain factor that is inversely proportional to the signal level.

Abstract: The mobile telephone is provided with the capability for automatically adjusting the gain of a microphone of the telephone based upon the detected noise level in which the cellular telephone is operated. As the noise level increases, the gain of the microphone is automatically decreased, thereby compensating for the natural tendency of telephone users to speak more loudly in noisy environments. Also, by decreasing the microphone gain, any clipping that might otherwise occur as a result of the user speaking more loudly is avoided and the signal-to-noise ratio is not thereby decreased. Furthermore, because the microphone gain decreases, the volume level of the voice of the user as it is output from the other party's telephone is not unduly loud. Hence, the other party need not manually decrease the speaker gain of his or her telephone.

Abstract: A receiver (10) includes an antenna (12), a preselector (14), an amplifier (16), a mixer (18), a filter (20), a signal strength measurement circuit (22), a radio frequency signal detector (26), and a processor (24). The processor (24) is programmed to receive a signal indicator level (42) from the signal strength measurement circuit (22), generate an automatic gain control command (44) based on the received signal indicator level (42), and send the automatic gain control command (44) to the amplifier (16) to control a gain of the amplifier (16). The processor (24) is programmed to receive an off channel signal strength (48) from the radio frequency signal detector (26), compare the off channel signal strength (48) to one or more threshold levels, generate a filter command (46), and send the filter command (46) to the filter (20). The filter command (46) identifies a cutoff frequency for the filter (20).

Abstract: A method and an apparatus for automating gain control of a radio frequency communication system can adapt a radio frequency communication system to an environment where a radio channel characteristic is rapidly or slowly changed. This can be achieved by extracting a maximum absolute value of a reception signal received by a receiver of a radio frequency communication system, determining a gain control value of the reception signal on the basis of the maximum absolute value and a predetermined threshold, and controlling gain of the reception signal according to the determined gain control value.

Abstract: In a channelized system having a plurality of channels, an input spectrum having a plurality of signals is received by a receiver (10). A first attenuation value (V1) is applied to a first variable gain device (12) and a second attenuation value (V2) is applied to a second variable gain device (14), wherein the first variable gain device (12) and the second variable gain device (14) are within a common signal path. The receiver (10) is tuned to a desired channel and a first power level is measured within the desired channel. The receiver (10) is selectively tuned to at least one additional channel and a second power level within the at least one additional channel is measured, independent of the first power level. Based on measuring the power levels, a first modified attenuation value is applied to the first variable gain device (12) and a second modified attenuation value is applied to the second variable gain device (14).

Abstract: A calibrated DC compensation system for a wireless communication device configured in a zero intermediate frequency (ZIF) architecture. The device includes a ZIF transceiver and a baseband processor, which further includes a calibrator that periodically performs a calibration procedure. The baseband processor includes gain control logic, DC control logic, a gain converter and the calibrator. The gain converter converts gain between the gain control logic and the DC control logic. The calibrator programs the gain converter with values determined during the calibration procedure. The gain converter may be a lookup table that stores gain conversion values based on measured gain of a baseband gain amplifier of the ZIF transceiver. The gain control logic may further include a gain adjust limiter that limits change of a gain adjust signal during operation based on a maximum limit or on one or more gain change limits.