Abstract: A method for adjusting automatic gain control of a radio receiver begins by determining power level of a radio frequency (RF) signal received by the radio receiver to produce a determined power level. The method then continues by comparing the determined power level with a plurality of power thresholds to determine whether an automatic gain adjustment is needed. The method then continues, when the automatic gain adjustment is needed, by determining, from the comparing the determined power level with the plurality of power thresholds, a sign of the automatic gain adjustment. The method continues by determining, from the comparing the determined power level with the plurality of power thresholds, a magnitude of the automatic gain adjustment. The method continues by addressing a gain adjustment look up table for at least a portion of the radio receiver based on the magnitude to produce a gain setting.

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. By altering the gain of the LNA by one step and measuring the difference between a prior RSSI_B reading and a subsequent RSSI_B? reading will indicate whether intermodulation interference is present.

Abstract: An automatic gain control loop for a radio receiver, comprising a switchable lowpass filter (21) to reduce distortions in an analogue gain control signal (6) by switching said switchable lowpass filter (21) to a low time constant in case a change of a gain control signal (6) of the automatic gain control loop lies above a predetermined threshold, which low time constant is lower than a normally used time constant, comprises a hold unit (24) which affects that said switchable lowpass filter (21) uses said low time constant a predetermined time after a change of the gain control signal (6) of the automatic gain control loop lies below said predetermined threshold.

Abstract: An amplitude modulation receiver including an antenna for receiving a signal and an input filter connected to the antenna. A variable gain amplifier is connected to the input filter and is responsive to a gain control signal. An A/D converter is connected to the variable gain amplifier and is responsive to a sampling signal and provides a sampled digital signal. A D/A converter receives a demodulated signal and provides an analog output signal. A controller receives and demodulates the sampled digital signal from the A/D converter, generates the gain control signal for the variable gain amplifier, generates the sampling signal for the A/D converter, and provides the demodulated signal to the D/A converter. The demodulation and generation of the gain control signal and the sampling signal are performed in software.

Abstract: In a radio reception apparatus, a variable gain of a reception amplifier is adjusted by an AGC control unit for each frame of a received signal for execution of an AGC operation. The AGC control unit determines and indicates to a digital signal processing unit an AGC operation end point of time. The digital signal processing unit executes prescribed signal processing on a digital signal obtained after the end of the AGC operation, in a known signal segment. Therefore, reception errors caused by erroneous amplitude values of digital signals resulting from the AGC operation can be prevented.

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: 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.

Abstract: An A-rail circuit outputs a control signal AGCOUTA whereas a B-rail circuit outputs a control signal AGCOUTB in an AGC circuit. AGCOUTA controls an AGC amplifier (A) while AGCOUTB controls an AGC amplifier (B). A difference value between a power of an input signal and (an amount of variable adjustment SWEEP+a power reference value AGCR). If an output signal of a loop filter in the A-rail circuit attains AGCARAIL>AGCATOB, AGCARAIL=AGCATOB is fixed, and AGCBRAIL is adjusted based on the difference value. If an output signal of a loop filter in the B-rail circuit attains AGCBRAIL<AGCBTOA, AGCBRAIL=AGCBTOA is fixed, and AGCARAIL is adjusted based on the difference value. A control circuit in the AGC circuit acquires a bit error rate, identifies a value of SWEEP allowing a minimum bit error rate, and fixes the value of SWEEP at the identified value.

Abstract: Disclosed is a linearization method in a mobile communication terminal wherein automatic gain control signals are divided into a plurality of entry regions, and which includes an initial value for a first entry region among the plurality of entry regions, a resolution constant and a slope character value for each entry region for generating a linear automatic gain control signal which guarantee a linearity of amplification gain of an amplifier.

Abstract: A DSRC car-mounted equipment for transmitting and receiving data to and from an on-the-road equipment, preventing communication error after the start of communication. The equipment comprises reception sensitivity-increasing means 14, 15, 40 for increasing the reception sensitivity in a communication area with the on-the-road equipment in response to the entrance into a communication start area with the on-the-road equipment, wherein the reception sensitivity-increasing means returns the reception sensitivity back to the normal reception sensitivity of before entering into the communication start area in response to the end of communication with the on-the-road equipment.

Abstract: Received signal characteristics of multiple concurrently received channels are determined using an analytical approach for computation in lieu of the measurement based approach of the prior art. A receiving wireless transmit receive unit (WTRU) and method are provided for processing concurrent communication signals from a plurality of transmitting WTRUs that concurrently transmit successive data blocks in a plurality of K forward channels. The receiving WTRU preferably has a receiver configured to receive successive data blocks of K concurrent transmissions transmitted from the transmitting WTRUs on the respective K forward channels. A processor is configured to compute individual channel characteristics for each forward channel k based on the characteristics of data signals received on all K forward channel.

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 circuit includes one or more first amplifiers operable to amplify an incoming signal to produce an amplified incoming signal. The incoming signal is associated with a desired signal. The circuit also includes a controller. In response to the amplified incoming signal exceeding a first threshold and the desired signal not exceeding a second threshold, the controller is operable to allow one or more second amplifiers to amplify the incoming signal and/or increase a current supplied to the one or more first amplifiers.

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: The invention provides an automatic gain control system that is implemented by digital hardware. The digital hardware determines the range of a set of digital data values, and then examines each digital data value in a sequence. An index counter increments a sample count index i each time a new digital data value is examined and determines the absolute value of the ith digital data value. The digital hardware also counts both the number j of digital data values that exceed a high percentage value of the range, and the number k of digital data values that are less than a low percentage value of the range as the digital hardware runs through the sequence. If the digital hardware determines that a digital data value is greater than the high percentage value, the ratio j/i exceeds a first threshold value, and the gain level is not set to the lowest gain level, then the gain is decreased.

Abstract: A communications apparatus and a frequency control method thereof, in that control of a reference frequency (local oscillator frequency) is made by feeding back a frequency offset estimate FOS to the voltage-controlled oscillator 103, and the frequency offset between sending and receiving frequencies is corrected by feeding back a frequency offset control value FOC which is based on a sending reference frequency command on downstream control data DCD to sending frequency offset control means 118, to control a sending reference frequency by using both a voltage-controlled oscillator 108 (a frequency control step) and sending frequency offset control means 118 (a sending frequency offset control step).

Abstract: In receiver systems for cellular phones using the W-CDMA method, the change in DC voltage occurring when the gain of a programmable gain amplifier (PGA circuit) is switched to adjust the gain for a received signal, can be suppressed. A sample-and-hold circuit is installed containing a “sample” mode for directly outputting a signal from the PGA section and also containing a “hold” mode for outputting the electric charge of a specified voltage stored in a capacitor. This sample-and-hold circuit normally operates in “sample” mode so the output signal from the PGA section is directly output, but is operated in “hold” mode at the gain switching timing of the PGA circuit, so that the electric charge of the specified voltage stored in the capacitor is output for a specified length of time (equal to the time required for the DC voltage change to converge to a stable level).

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 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: An automatic gain control system is provided. A signal path is configured to receive an input signal. The signal path includes a first amplifier that has a control input. A first signal level detector is coupled to the signal path, the first signal level detector having a signal level output. A gain control device having a first signal level input is coupled to the signal level output of the first signal level detector. The gain control device also has a first control output coupled to the control input of the first amplifier, and a gain control configuration input. A processor, coupled to the gain control configuration input of the gain control device, is configured to monitor operating conditions and to reconfigure the gain control device in response to changes in the operating conditions.

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: A mobile communication system having an AGC (Automatic Gain Control) function includes an apparatus for adaptively controlling an output level of a local oscillator to reduce nonlinear distortion which may occur when a high-power RF signal is received or when it is necessary to transmit a high-power transmission signal. When a high-power RF signal is applied to a first stage in a receiving stage, the apparatus prevents the signal input to a reception AGC loop from being distorted by decreasing an output level of the local oscillator, which is provided to a down-converter. Further, when the output signal of a transmission stage has a high power level, the apparatus decreases the output level of a transmission AGC amplifier and instead increases the output level of the local oscillator, which is input to an up-converter located in an IF stage, so that it is possible to obtain a nonlinear distortion-reduced signal while obtaining the same output level.

Abstract: A reception apparatus and a reception processing method are proposed to improve a reception characteristic by compensating deterioration of transmission quality independently of the traveling speed of a terminal. When a transmission signal sent via a radio transmission path is received and data is demodulated by carrying out various kinds of reception processing on the received signal, the present invention can perform reception processing best suited to a radio transmission path whose state changes according to the traveling speed of the terminal itself by receiving traveling speed information from speed detection means for detecting the traveling speed of the terminal itself and controlling reception processing on the reception signal according to the traveling speed information.

Abstract: An automatic gain control (AGC) system (100) for a controlled gain receiver (1101) includes a magnitude generator (160) and a gain corrector (170). The magnitude generator (160) generates a binary voltage squared signal (165) having a binary value that is directly proportional to a recovered signal power of an intercepted signal (113). The gain corrector (170) determines an adjustment of a gain control value (195) as a multiple of increments that are approximately 3 decibel (dB), by shifting (475, 445) a reference threshold by one or more bits and comparing (485, 455) the shifted reference threshold to the binary voltage squared signal. An initial setting of a state of a step attenuator (114) during a track mode (172) is determined during a warm up mode (171) by comparing the binary voltage squared signal (165) to two different thresholds (245, 255).

Abstract: An automatic gain controller and a receiver having the automatic gain controller, which obtains a stable fine reception quality without influences of the receiving channel or the receiving radio wave is provided. It is provided with the reception quality detector 20 for detecting the reception quality of the diffusion of the constellation, the error correction ratio or the error rate, so as to setup the optimal standard revel (TOP) by switching the reference level (TOP) for switching the IF_AGC operation and the RF_AGC operation according to the reception quality. As a result, it determines the degradation of the reception quality caused by the non-linear distortion or the insufficiency of the C/N according to the radio frequency efficiency that differs from each channel or the receiving radio wave such as a level of the adjacent channel, so as to setup the optimal receiving condition.

Abstract: A wireless communication device (WCD) performs DC removal on a received signal using a coarse DC removal unit that removes relatively large DC components and a fine DC removal loop that removes residual DC components. The coarse DC removal unit can implemented in a receiver, and the fine DC removal loop can be implemented in a modem. In addition, a coarse DC estimation loop implemented on the modem may be coupled to the coarse DC removal unit to update DC offset values stored in the DC removal unit. By storing coarse DC offset values locally on the receiver, DC removal can be achieved very quickly.

Abstract: An aviation radio receiver provides automatic gain control in three zones including an RF zone employing an RF attenuator (14), an intermediate frequency zone employing an intermediate frequency logarithmic attenuator (26) and a baseband zone implemented in a digital processor (30).

Abstract: A method and apparatus for dynamically controlling a programmable gain amplifier (PGA) in a radio receiver to provide a plurality of gain steps thereby providing automatic gain control (AGC) in a receiver intermediate frequency (IF) stage comprises an analogy peak detector formed to including a constant current source and a plurality of MOSFETs all configured to produce an output voltage (DC) whose value reflects a peak amplitude of a received differential quadrature phase shift keyed (QPSK) signal. A first circuit portion generates currents that are proportional to the square of the magnitude of the gate to source voltage for each of a plurality of MOSFETs coupled to receive the differential QPSK signal and a second circuit portion produces a voltage that is equal to the square root of the sum of the squares of the currents produced (drawn) by the MOSFETs of the first circuit portion.

Abstract: Saturation of an RF front end in a radio receiver is prevented when receiving a desired radio broadcast signal via an antenna in the presence of a strong, undesired radio broadcast signal within a passband of the RF front end. An antenna signal from the antenna is coupled to the RF front end, thereby generating an amplified signal. The radio receiver demodulates the desired radio broadcast signal in response to the amplified signal, thereby generating a demodulated signal. A signal-to-noise quality parameter of the demodulated signal is determined. The antenna signal is attenuated prior to coupling it to the RF front end by an attenuation determined in response to the signal-to-noise quality parameter.

Abstract: An automatic gain control (AGC) system controls a receiver having multiple amplifier stages with near constant compression. The AGC system controls gain, and thus compression, of each stage employing information generated by the other stages to generate feedback signals at a system level. A central controller uses threshold detection to monitor signal power at each stage of the receiver signal path as well as overall signal gain. Based on these various signal power measurements, the central controller adjusts signal gain of the input to one or more stages, while maintaining overall signal gain for a constant output signal level. The AGC function may be implemented by switching the gain of each stage's variable amplifier in discrete steps in discrete steps, with the step size being coarser for stages closer to the input signal than those closer to the final output baseband signal.

Abstract: A radio receiver comprises an LNA which amplifies An RF signal, a quadrature demodulator which directly demodulates the amplified RF signal into a B/B signal, using a LO signal, a VGA which amplifies the B/B signal, a DC offset canceller which executes feedback control on the amplified B/B signal, and a gain controller which controls at least the gain of the LNA, the gain controller including a signal intensity detector which detects the intensity of the amplified B/B signal, a gain selector which selects a desired one of preset gains on the basis of the detected intensity, a timing controller which controls timing of switching to the selected desired gain, and a gain control signal generator which changes, in accordance with the controlled timing, the interval at which an LNA gain control signal is generated.

Abstract: In a code division multiple access wireless communication system having at least one base transceiver station and at least one mobile station having a mobile station receiver assembly configured to receive a coded signal having an information-bearing signal portion and an associated interfering signal portion from the base transceiver station, a method and apparatus for automatic gain control compensation in the mobile station receiver assembly, is disclosed. The method includes causing a gain adjustment to the coded signal by an AGC circuit in the mobile station receiver assembly to produce a post-AGC signal having a post-AGC interfering signal portion with an associated post-AGC interfering signal power level, and an associated gain error value. The method further includes compensating for the gain adjustment to the coded signal if the number of receiver fingers assigned to demodulate the coded signal is less than or equal to a predetermined number.

Abstract: An RF device including a control loop for maximizing output power for each of several data rates or constellation types. The RF device includes a power detector, a power amplifier and a MAC that includes input and output adjust circuits. A power level value is generated from measured output power. The MAC compares an adjusted power level value with a set point value and generates an error value. The MAC adjusts a power control value based on the error value for controlling the gain of the power amplifier. The MAC uses a data rate signal indicative of a selected constellation type or data rate. The input adjust circuit stores one or more input adjustment values selected by the data select signal for adjusting the power level value. The output adjust circuit stores one or more output adjustment values selected by the data select signal for adjusting the power control value.

Abstract: An automatic simulcast correction method (300) for a selective call receiver (100) includes the steps of measuring a received signal (304) for a received signal strength indication measurement and then determining if a protocol indicates a simulcast signal (310). If the received signal strength indication measurement is above a predefined threshold and the protocol indicates the simulcast signal, then the selective call receiver is optimized for simulcast delay spread distortion (312). If the received signal strength indication measurement is below a predefined threshold or the protocol does not indicate the simulcast signal, then the selective call receiver is optimized for static sensitivity (314).

Abstract: An automatic gain control loop for a radio receiver, comprising a switchable lowpass filter (21) to reduce distortions in an analogue gain control signal (6) by switching said switchable lowpass filter (21) to a low time constant in case a change of a gain control signal (6) of the automatic gain control loop lies above a predetermined threshold, which low time constant is lower than a normally used time constant, comprises a hold unit (24) which affects that said switchable lowpass filter (21) uses said low time constant a predetermined time after a change of the gain control signal (6) of the automatic gain control loop lies below said predetermined threshold.

Abstract: An automatic gain control circuit in a receiver estimates an AGC gain using information from an estimated amplitude signal derived from a received signal before a carrier signal is recovered from the received signal. The carrier signal is recovered from the received signal using the estimated AGC gain. After the carrier signal is recovered, the amplitude of the estimated amplitude signal decreases below the amplitude of the recovered carrier signal. The Automatic Gain Control circuit uses the amplitude of the recovered I and/or Q signal to accurately set the AGC gain.

Abstract: A control word generator comprised of circuitry to generate a control word to control an attenuator. The control word generator includes a counter that increments at a clock rate much higher than the refresh rate at which the error signal is recalculated. The counter is controlled by a comparator which compares the error signal to a reference value, which, starting from a programmable upper limited is decremented in the counter's incrementation rate by a programmable step size. When the reference value equals the error signal, the comparator changes state and the counter stops incrementing. The count at that time is the control word, which if everything operated instantaneously, would be the control word that would alter the attenuation sufficiently to achieve nominal power.

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.

Abstract: The present invention reduces automatic gain control (AGC) transients using first and second AGC processing branches to receive a signal. A gain is selectively adjusted (if desired) in the one of the AGC processing branches during a first time period. However, a gain is not adjusted in the other AGC processing branch during that first time period. The signals generated by the first and second AGC processing branches are then diversity processed to generate a received signal. The diversity processing effectively reduces the effect of any AGC transient.

Abstract: A receiving apparatus and method which can prevent second order harmonic interference and beat interference in a direct orthogonal detector is disclosed. When a control signal of the high level is inputted to a control terminal, then a first high frequency switch diode is turned on and a second high frequency switch diode is turned off. In this instance, a filter circuit functions as a low-pass filter. When a control signal of a low level is inputted to the control terminal, then the first high frequency switch diode is turned off and the second high frequency switch diode is turned on. In this instance, the filter circuit functions as a high-pass filter.

Abstract: Overload distortion protection for a wideband receiver having a wideband variable gain input amplifier followed by a frequency conversion stage followed in turn by an intermediate frequency amplifier and detector to produce a measurement value in response to a signal input to the wideband variable gain input amplifier is achieved by detecting the peak power of the signal at the output of the wideband variable gain input amplifier and comparing it with the power output from the intermediate frequency amplifier and detector. If a threshold difference is exceeded, gain control signals for the wideband variable gain input and intermediate frequency amplifiers are adjusted for optimum dynamic range. If there is no range for adjusting the gain control signals, then a warning is provided to an operator to alert that the measurement value may contain distortion.

Abstract: A first control unit reads out both specific frequencies and gain data corresponding to these specific frequencies, which have been stored into a first storage unit, and approximates gain data corresponding to an arbitrary frequency by way of a linear function to calculate the gain data by executing a formula. A D/A converter converts this gain data into a gain control signal, and supplies the gain control signal to a variable gain amplifier. The variable gain amplifier amplifies a transmission signal by a gain defined in response to a transmission frequency based upon the gain control signal.

Abstract: A receiving apparatus comprising a gain control amplifier, a gain controller and a level detection circuit. The gain controller controls a gain of the gain control amplifier. The level detection circuit specifies a range of strengths of received signals based on a signal coupled to an input of the gain control amplifier. The gain controller controls the gain of the gain control amplifier based on the range of the strengths of the received signals.

Abstract: A combiner for a diversity radio receiver wherein amplitude inversion of either received signal is performed, on a selection basis, in order to maximize the resultant output combined signal. The strength of each diversity signal is monitored as well as the strength of the combined output signal. A gain control engine combines the stronger signal with either the inverted or non-inverted weaker signal to maximize the combined output (resultant) signal strength. According to another embodiment the combiner may additionally perform an amplitude adjustment whereby the in-channel noise power is also monitored and the individual channel signal-to-noise ratios are used to adjust the amplifier gains. In this embodiment the individual channel signal-to-noise ratios plus the strength of the combined output signal are used to decide whether to invert the weaker signal before combining the received signals.

Abstract: A wireless or wired communication system and method is provided including a transmitter and a receiver. A RF communication system in accordance with the present invention includes an apparatus and gain control method between RF receiver and baseband modem in case of a plurality of gain stages inside a receiver. The gain of each stage can be controlled by an integrated gain controller. The gain controller monitors the signal level of each gain stage to place its gain to optimal value. The gain control apparatus and method can be implemented in a digital AGC system. The gain controller accepts a signal implementing gain control and thus there is no stability issue. When distributed gain stages are present inside a related art receiver and separate gain control loops are used, stability issues can arise. In a preferred embodiment of an apparatus and method, the baseband modem decides the amount of gain control and adjusts the gain of certain gain stages by the proper amount.

Abstract: A satellite communication system includes at least one spacecraft in geosynchronous orbit for providing a plurality of beams on the surface of the earth, and a plurality of ground stations individual ones of which are located in one of the beams for transmitting uplink signals to the spacecraft. The spacecraft has a plurality of receivers for receiving a plurality of the uplinked signals from ground stations, a frequency translator for translating the received uplink signals to a transmission frequency of a plurality of downlink signals, and a plurality of transmitters for transmitting the plurality of downlink signals within the same beams as the corresponding uplink signals. Each transmitter includes a combiner for combining together a plurality of frequency translated signals and a power amplifier, such as a TWTA, for amplifying the combined plurality of frequency translated signals.

Abstract: An apparatus for controlling the power level of an output signal from the output of an electronic amplifier. The electronic amplifier has a control signal input for receiving an amplifier control signal and has a power input for receiving current from a power supply. The apparatus comprises an amplifier output power detector, coupled to the output of the amplifier, used for generating a power measurement signal representing the output power of the amplifier. The apparatus contains a current detector arranged to detect the current received by the amplifier from the power supply and to provide a current measurement signal dependent on the amount of current received from the power supply. The apparatus contains a digital signal processor which receives the current measurement signal and provides a reference signal dependant on the current measurement signal.

Abstract: A fast attack Automatic Gain Control (AGC) loop (100) having the capability to selectably shape one or more decaying current sources (242, 260) contained within an off-channel feedback loop and an on-channel feedback loop of the AGC loop by sequentially and selectively switching out weighted transistors (Tr0, Tr1, Tr2, . . . , Tr10) of a plurality of weighted current mirrors (313, 379, 453, 519) at predetermined intervals (t0, t1, t2, . . . , t10).

Abstract: A receiver comprising analog signal processing means, intermodulation interference detection means and an automatic gain control circuit for controlling the gain of said analog signal processing means, in which an output of the analog signal processing means is coupled through frequency selective means for channel selection and an amplitude detector to a first terminal of the intermodulation interference detection means. A signal generator is used to generate a gain modulation signal being coupled to a gain control input of said analog signal processing means as well as to a second terminal of the intermodulation interference detection means.

Abstract: There is provided a radio type selective calling receiver including (a) a front end for converting a received signal into a first signal having an intermediate frequency, (b) a detector for detecting an electric field strength, based on the first signal, and demodulating the first signal, (c) a decoder for analyzing the thus demodulated first signal, (d) a voltage to current converter for converting a voltage defined by the electric field strength into a current, and (e) an automatic gain controller for receiving the voltage. In accordance with the radio type selective calling receiver, it is possible to accurately operate the automatic gain controller (AGC) without a drop in an input signal.