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: A radio communication apparatus includes a radio signal processing section which produces a first signal. A power calculation section produces a power value signal of the first signal. A correlation detection section produces correlative value signals corresponding to a correlation between the first signal and a known signal. A first and a second detection section detect a beginning of the reception signal, using the power value signal and the correlative value signal respectively. The first and the second detection section respectively produce a first detection and a second detection signal, each of which include information of a beginning timing of the reception signal. A select control section is supplied with the first and the second detection signals and selectively outputs one of them. A demodulation section demodulates a data signal from the first signal using an output signal from the select control section.

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

Abstract: The AGC threshold of electric intensity level is set by the signal processor portion 107 in response to the measured result of the error rate measuring circuit 109 that measures the error rate of the received signal, and the gain control operation of the gain control circuit 106 is caused to start when the electric field intensity detected by the field intensity detector 105 reaches the threshold of electric intensity level. Accordingly, the optimum AGC threshold of electric intensity level can be set to meet the radio wave situation in which the radio receiver, i.e., the receiving situation of the received signal and also the gain control of the gain controlling means can be achieved to optimize the signal quality of the received signal in the situation of either the IM characteristic or the electric field variation characteristic, e.g., under the environment of the strong electric field IM or the environment in which the electric field is changed strongly.

Abstract: A receiver circuit for a mobile radio receiver has a controllable amplifier with a variable gain level, an analog-digital converter stage, a digital filter configuration for the purpose of channel selection and a signal strength estimator. The signal strength estimator is connected downstream of the filter configuration in the signal path and has the purpose of determining the signal strength in the selected user signal. The amplifier is controlled in dependence on the user-channel signal strength determined by the signal strength estimator.

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: In a gain control device for packet signal receiver, a variable gain amplifier amplifies an input signal with a gain corresponding to a control voltage applied thereto, and a power detector detects output power of the variable gain amplifier. A packet detection circuit detects a packet signal based on the detected output power. A control circuit outputs the control voltage variable with the detected output power, and the control voltage is provided for the amplifier. Thus high-speed gain control is performed immediately after the start of detection of the packet signal. When the elapsed time after the start of detection of the packet signal exceeds a predetermined time, a sample-hold circuit sample-and-holds the control voltage. This control voltage is provided for the amplifier up to the end of reception of the packet signal thereafter. Thus low-speed gain control is performed to provide stable power without distorting the signal wave.

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: 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 wireless communication apparatus includes an antenna receiving a radio signal, a variable gain amplifier amplifying the received signal using a variable gain, an analog-to-digital converter converting the amplified signal into a digital signal, a gain setting unit periodically updating the gain of the variable gain amplifier in accordance with an output from the analog-to-digital converter, and an operating mode selection unit selecting one of a plurality of operating modes characterized by different gain updating periods in accordance with the output from the analog-to-digital converter, the selected operating mode being set in the gain setting unit. With this construction, the precision in conversion by the analog-to-digital converter is maintained at a proper level when an environment for signal reception varies.

Abstract: An automatic gain control (AGC) circuit including: a forward transmission path (214) having applied at its input an input RF signal and to provide at its output an output signal; a variable gain AGC amplifier (210) in the forward transmission path for processing the input RF signal, which amplifier has a control input 240 and is responsive to a control signal applied at its control input to vary its gain; a feedback loop (220 to 240), coupled from the output of the forward transmission path and to the control input of the AGC amplifier; an integrator (230, 232), coupled to the control input of the amplifier; a voltage source (234), coupled to the integrator and to the control input of the amplifier; and a further variable gain device (215) for varying the gain or attenuation of a signal applied to the control input of the AGC amplifier.

Abstract: The invention aims to minimize the analogue/digital converter over-dimensioning within the framework of reception of signals originating from a satellite and exhibiting power levels which can vary over time. The invention proposes a technique of automatic gain control which handles the setting of the noise level associated with the amplified signal. The automatic gain control is achieved by neutralizing the signal received by the antenna, and by adjusting the gain during the neutralization of the signal received until a predetermined noise level is obtained at the end of the reception facility. The invention also pertains to a device comprising the means for implementing the method.

Abstract: A switchable gain amplifier for use in mobile communications devices is provided, having a first amplifier stage having a first gain, a second amplifier stage connected in parallel with the first amplifier stage. The first and second amplifier stage have different gains and a gain controller, connected to the first amplifier stage and to the second amplifier stage, enables only one of the amplifier stages at a time.

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 AGC circuit maintains a fixed level for starting AGC operation for an interference wave even if the local oscillation frequency is switched in a receiver that has a plurality of local oscillation frequencies. A frequency correction circuit for correcting the conversion gain characteristic from the antenna input up to the mixer output is provided for the input of a detector within the AGC control loop. The frequency correction circuit is provided with a trap circuit that has a fixed trap frequency by using an LC resonance circuit, for example.

Abstract: A digital automatic gain control (AGC) circuit for use in a radio frequency (RF) receiver. The AGC circuit comprises: 1) a first shifter for receiving an in-phase signal as a first series of X-bit samples and left-shifting each X-bit sample by a number of bits determined by a coarse scaling factor; 2) a first limiter for receiving the D most significant bits of the output of the first shifter and outputting a subset of the D most significant bits of the first shifter output; 3) a first multiplier for multiplying the subset of the D most significant bits of the first shifter output by a fine scaling factor to produce a first M-bit product; and 4) a gain adjustment circuit for comparing a power signal derived from the first M-bit product to a maximum threshold value and generating the coarse scaling factor and the fine scaling factor.

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: A radio receiver portion of a transceiver includes a differential amplifier that is used to provide a fast response. A pair of input MOSFETs of the differential amplifier stage are coupled to an active load. A voltage follower circuit is coupled to each output stage of the two stage differential amplifier to drive a current through a load without reducing the output voltage. The voltage follower stages each include a current mirror that replicates current level defined by an input MOSFET of the voltage follower circuit and, by its configuration, a voltage level produced by the differential amplifier to the input MOSFET of the voltage follower circuit. Accordingly, the differential amplifier stage defines the amplification of the circuit while the voltage follower circuits replicate the amplified output with the ability to drive a load.

Abstract: A packet-based wireless transceiver that transmits and receives data packets includes a transceiver component having an adjustable performance parameter. A calibration circuit adjusts the performance parameter of the transceiver component at times synchronized with the data packets. A calibration signal generator generates calibration signals based on the performance parameter and outputs the calibration signals to the transceiver component. A comparator receives the outputs of the transceiver component and generates a difference signal. A calibration adjustment circuit communicates with the calibration signal generator and the comparator and adjusts the performance parameter to reduce the difference signal. Alternately, a reference signal generator generates a reference signal. A comparator receives the reference signal and a second signal from the transceiver component and generates a difference signal.

Abstract: In a direct conversion radio frequency receiver, an automatic gain control is implemented that allows changing the operation mode of a filter unit in the baseband section of the receiver such that in a first operation mode filter capacities are selected to provide desired output signal characteristics, whereas in a second operation mode the filter settling time is significantly reduced in order to speed up gain adaptation and to improve gain loop stability. In one embodiment the cut-off frequency of a high pass filter and the Q-factor of a subsequent low pass filter are increased and decreased respectively upon changing the gain setting of a variable gain amplifier to accelerate settling of the filter.

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: Receiver comprising a resonance amplifier for selectively amplifying a modulated carrier signal being coupled to signal demodulator for narrow band demodulation. The resonance amplifier comprising a cascade of first and second transconductance amplifiers (TC1, TC2) being included in a loop, outputs thereof being coupled via first and second parallel RC filters (R1C1; R2C2) to inputs of the second and first transconductance amplifiers (TC1, TC2), respectively, the loop also includes a signal inverter (INV) for signal inversion.

Abstract: A filter module for reducing a DC offset voltage in a radio frequency communication channel is described. A first capacitor is coupled between a first differential input node and a first differential output node. A second capacitor is coupled between a second differential input node and a second differential output node. An active variable resistor is coupled between the first differential output node and the second differential output node. The active variable resistor receives a control signal. The control signal adjusts the value of the active variable resistor, which adjusts the frequency response of the filter module. The rate at which the filter module reduces DC offset voltages is thereby adjusted. The filter module is also adaptable to single-ended applications.

Abstract: An automatic gain control circuit with a very wide operational range, less hardware, and faster response, and more flexibility includes a signal strength estimator, a gain adjusting factor device and a multiplier. After the signal strength estimator finds signal strength, the gain adjusting factor device will generate a gain adjusting factor corresponding to the signal strength. Then the multiplier will update gain by multiplying it the gain adjusting factor.

Abstract: A circuit for compensating temperature of an automatic gain control (AGC) circuit includes a low noise amplifier (LNA) for amplifying a received radio frequency (RF) signal, an attenuation control unit for generating an attenuation control signal by sensing the amplified RF signal, and a PIN diode attenuator for attenuating the RF signal inputted to the LNA by driving the PIN diode with an attenuation control signal. A temperature compensation unit for compensating an attenuation change amount of the PIN diode caused by the change of temperature compensates the voltage change between the PIN diodes by using an additional PIN diode having identical characteristic of temperature as the PIN diode of the PIN diode attenuator.

Abstract: A communications device includes a frequency conversion circuit and a control circuit. An antenna receives a radio signal at a first frequency and converts it into a radio frequency (RF) signal of the first frequency. The frequency conversion circuit is associated with the antenna and configured to convert the RF signal into a first signal component and a second signal component. The first and second signal components occupy a baseband. The control circuit has first ports connected to the frequency conversion circuit to receive the first and second signal components and second ports connected to a processor circuit to output amplified first and second signal components, and separate channels for the first and second signal components existing between the first and second ports. Each channel comprises an amplifier and a feedback loop configured to control the amplifier as a function of a reference signal and a control signal derived from the RF signal.

Abstract: A method of obtaining optimum RF performance for a slave base station when co-siting a master base station with said slave base station involves calculating operating characteristics of the slave base station that is sharing an antenna assembly with the master base station. The third order intercept (IP3) and the noise figure (NF) characteristics of the slave base station are calculated and plotted versus a range of upfront gain values. The plots are studied and compared against vendor specifications and standalone performance characteristics. A desired upfront gain value is then selected to achieve a particular IP3 and NF characteristic for the slave base station. Upon selection, the upfront gain supplied to the slave base station is adjusted via an attenuator placed in-line before the slave base station to match the desired upfront gain.

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: 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: A receiver is adaptively calibrated by using a coherent reference signal. The reference signal is selected to be offset from a center frequency of the calibration signal such that the resultant product is offset from baseband by some small amount. The resultant product is used to determine a next value of the calibration parameters.

Abstract: The present invention relates to receivers such as multi-carrier receivers. An orthogonal frequency division multiplex (OFDM) receiver in a terrestrial digital video broadcast (DVB-T) network is required to operate in a complex channel environment, wherein high power analogue television signals may co-exist. The mix of high power analogue television signals and lower power digital signals results primarily from the concurrent existence of both analogue and digital television services. The present invention provides a receiver having improved power efficiency.

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: A radio communication apparatus includes a radio signal processing section which produces a first signal. A power calculation section produces a power value signal of the first signal. A correlation detection section produces correlative value signals corresponding to a correlation between the first signal and a known signal. A first and a second detection section detect a beginning of the reception signal, using the power value signal and the correlative value signal respectively. The first and the second detection section respectively produce a first detection and a second detection signal, each of which include information of a beginning timing of the reception signal. A select control section is supplied with the first and the second detection signals and selectively outputs one of them. A demodulation section demodulates a data signal from the first signal using an output signal from the select control section.

Abstract: Disclosed is an RF transmitter circuit (10), as well as a method for operating the circuit. The RF transmitter circuit includes a VGA (20), that includes circuitry for generating a feedback signal, and a temperature compensation block (18) having an input coupled to a gain control signal and an output coupled to an input of the VGA for providing to the VGA a compensated gain control signal. The temperature compensation block further includes a bias input that receives the VGA feedback signal. The VGA feedback signal operates to modify the gain control signal to reduce an amount of variability in a VGA gain slope over a range of VGA output power.

Abstract: A method and circuit for compensating for a DC offset generated in a signal processing apparatus are disclosed.

Abstract: The automatic gain control method with little being influenced of the unnecessary electric wave, even if strong unnecessary electric wave is near the frequency of input signal, is offered by carrying out change of the delay point level. The automatic gain control system with a scale of few circuit, having low noise property and high adjacent disturbance oppression property, is offered. When the IF AGC signal 112 is smaller than delay point level, the output agcerr of the signal level detector 614 is provided to the 1st loop filter 105. Since the IF AGC signal 112 provided to the IF AGC amplifier 608 is value responding to signal level of IF signal, output is fed back to this amplifier, and control of IF gain is performed automatically. On the other hand, when output of the 2nd loop filter 106 is “0”, output rfzero of the 2nd comparator 108 is set to 1, and “0” is provided to the 2nd loop filter 106.

Abstract: Briefly, in accordance with one embodiment of the invention, a wireless device has an array of antennas. A signal is provided to one of the antenna by two variable gain amplifiers, one of which processes a signal that is shifted in phase compared to the signal processed by the other variable gain amplifier.

Abstract: Systems and techniques for gain control include amplifying a signal with an amplifier having a gain represented by one of a plurality of gain curves depending on a value of a parameter, the signal being amplified at a first one of the parameter values, and controlling the gain of the amplified signal from a predetermined gain curve relating to the gain curve of the amplifier for a second one of the parameter values by adjusting a gain control signal corresponding to a point on the predetermined gain curve as a function of the first one of the parameter values, and applying the adjusted gain control signal to the amplifier. 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.

Abstract: A constant output signal can be achieved by controlling a gain variable amplifier 2 based on a level of an output signal which is derived by variably amplifying a receiving signal S1 (input signal). An AGC output signal S11 is detected by a detector circuit 3. Then, a CPU 5 generates a control signal S8 based on a detected voltage signal S7. An RSSI detector portion 9 detects an RSSI signal S10 corresponding to a transmitting signal level from the receiving signal S1. The transmitting signal level is compared to a preceding transmitting signal level. The control signal from a preceding execution of the gain control is output if the present control signal is lower than the preceding control signal and the present transmitting signal level is reduced below the preceding transmitting signal level.

Abstract: A receiver for a digital broadcasting service have a compatibility between tuning to a desired channel at a short period of time and an improve ment of a bit error rate (BER) characteristics. In a case where a target wave is fluctuated, to prevent the receiver from having a significant declination of BER characteristics and to ensure the reproduction of high quality images, the receiver includes an automatic gain controller including a loop filter in which the frequency range of the loop filter can be switched according to an output of a synchronous state discriminator. The frequency band of the loop filter is selectively adjusted to one setting designed for minimizing the duration for tuning a desired channel before a synchronous state is established. After the synchronous state established, the frequency band of the loop filter is switched to another setting designed for enhancing BER characteristics.

Abstract: AM receiver comprising an RF input circuit for receiving an RF AM signal, demodulation means providing an audio signal carried by said RF AM signal as well as automatic gain control means for stabilising an RF carrier dependent DC level at the output of said demodulation means at a substantially fixed stabilisation value. In order to improve the receiver performance in particular at low values of the RF reception fieldstrength, the RF input circuit is being provided with a cascade of N tuneable resonance amplifiers being tuned to said RF AM signal, said automatic gain control means controlling at least one of said cascade of N resonance amplifiers to increase in both gain and selectivity at a decrease of the fieldstrength of said RF input signal.

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 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: To ensure AGC control with a quick response to each signal from any of a plurality of wireless communication terminal devices in a wireless LAN, AGC control is conducted by receiving signals from respective wireless terminals in control slots in one frame, detecting the signal level in a signal level detector circuit, then comparing it with a predetermined level in a level comparator circuit, and supplying the comparison value to VGA via a in loop filter. In this case, control values are stored in RAM. Thus, by identifying the terminal under transmission and reading out a control value for the terminal under transmission, AGC control is executed. As a result, when the terminal under transmission changes from one to another the, AGC loop can quickly follow this change.

Abstract: A switchable gain amplifier for use in mobile communications devices is provided, having a first amplifier stage having a first gain, a second amplifier stage connected in parallel with the first amplifier stage. The first and second amplifier stage have different gains and a gain controller, connected to the first amplifier stage and to the second amplifier stage, enables only one of the amplifier stages at a time.

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: A signal processing unit 107 outputs a control parameter of a gain control operation-starting electric field strength value in the form of a signal CN1 in correspondence with data of transfer speed/number of FM level by referring to a memory 108. Then, this signal processing unit 107 controls setting of an Received Signal Strength Indicator 105. When an electric field strength of a signal reaches an operation-starting electric field strength value, the Received Signal Strength Indicator (RSSI) 105 changes a voltage of an output GC1 based upon the control parameter (signal CN1). A gain control circuit 106 changes a gain control amount in response to the output signal GC1 derived from the Received Signal Strength Indicator 105. As a consequence, the operation-starting electric field strength value of the AGC operation can be set under optimum condition in correspondence with the sort of signal.

Abstract: Systems and techniques for gain control include amplifying a signal with an amplifier having a gain represented by one of a plurality of gain curves depending on a value of a parameter, the signal being amplified at a first one of the parameter values, and controlling the gain of the amplified signal from a predetermined gain curve relating to the gain curve of the amplifier for a second one of the parameter values by adjusting a gain control signal corresponding to a point on the predetermined gain curve as a function of the first one of the parameter values, and applying the adjusted gain control signal to the amplifier. 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.

Abstract: A mobile radio communication apparatus comprises a power amplifier (102) for power-amplifying a transmission signal (103) into an amplified transmission signal which is transmitted through an antenna (101). A high-sensitivity detector (105) high-sensitivity detects the amplified transmission signal. The high-sensitivity detection signal is limited by a diode (107) to a predetermined voltage to be produced as a first output voltage signal. A low-sensitivity detector (110) low-sensitivity detects the amplified transmission signal. A predetermined offset voltage is superposed on the low-sensitivity detection signal to be produced as a second output voltage signal. The first and the second output voltage signals are combined into a combined output signal. A comparator (118) compares the combined output signal with a transmission ramp production signal supplied from a mobile radio communication apparatus control section. With reference to a comparison result, a dynamic range of the power amplifier is controlled.