Abstract: An active bias circuit 30 connected to a power amplifier PA maintains a power amplifier DC quiescent current at a fixed value over a wide temperature range. The active bias circuit 30 includes first and second current mirror circuits 32, 34. The power amplifier PA is an element of the second current mirror circuit 34. A temperature compensation circuit 42 is connected to the first current mirror circuit 32 for providing temperature compensation therewith. A first reference voltage source is connected to the first current mirror circuit 32 by way of the temperature compensation circuit 42 for providing a first reference voltage Vref to the first current mirror circuit 32. A current sink 36 is connected to a transistor of the first current mirror circuit 32 and a voltage source adjustment circuit 38 is connected to the first current mirror circuit 32 for setting a voltage provided to the first current mirror circuit 32.

Abstract: This invention relates to an amplifier having digital micro-processor control apparatus and, in particular, to a high frequency power amplifier that includes a micro-processor control system to accurately regulate the operating point of the various amplifying elements in the high frequency power amplifier. The basic amplifier circuitry consists of a micro-controller, a variable voltage attenuator (VVA), a digital to analogue converter and an EEPROM. The EEPROM provides a lookup table which is read by the micro-controller, which then writes to the digital to analogue converter to set the control voltage to the variable voltage attenuator.

Abstract: A system is disclosed for improving the operation of a circuit having one or more semiconductor devices as temperature varies over the circuit's typical range of operating temperatures. In an environment of a current mirror, the invention can be used to reduce variation in the reference current as temperature changes. This is particularly desirable at low operating voltages. In one embodiment, the invention is configured as a current compensation module connected to a current mirror regulator node. At normal temperature, the current mirror reference current and the compensation module are configured to provide the desired amount of reference current to the current mirror. At temperatures above normal, the current compensation module automatically conducts more current than at normal temperature. At temperatures below normal, the current compensation module conducts less current than at normal temperature.

Abstract: An audio amplifier power and temperature controller and associated methods are provided. The controller preferably includes a power receiving circuit positioned to receive power from a power source to an audio amplifier and a power condition switching control circuit responsive to the power receiving circuit to switch components of an audio amplifier during a plurality of power conditions. The power condition switching control circuit preferably includes a soft start circuit responsive to the power receiving circuit to limit inrush current from the power receiving circuit and to slowly ramp up to an audio amplifier on-state and a thermal status monitoring and controlling circuit to monitor thermal status of operating values of audio amplifier components and responsively decrease power to the audio amplifier components to protect the audio amplifier components against damage caused by excess heat and responsively increase power when the audio amplifier components return to normal thermal operating conditions.

Abstract: A device for converting low currents, applied by a non-ideal current source to an input of the device, into voltage signals comprises a converter for converting the low currents into voltage signals, at least one feedback branch, and a coupler. The output of the converter is fed back to an input of the converter by the feedback branches and the coupler. The coupler is wired so that control currents supplied by the feedback branches are applied to the input of the converter via the coupler to control the low currents applied by the non-ideal current source at the input of the device. The control currents are applied to the input of the converter via the coupler with a reduction of capacitive, inductive, and ohmic influence of the feedback branches and with an amplitude matching of the control currents.

Abstract: Two compensating resistors in a mirror bias circuit coupled to a radio frequency (RF) amplifier are configured such that transistor base-emitter voltages are adjusted to stabilize RF transistor quiescent current for variations in collector voltage, Vcc. For example, when battery power is drained during device use, Vcc decreases. As Vcc decreases, less current is drawn through the compensating resistors, thereby decreasing the voltage drop across the compensating resistors and increasing the transistor base-emitter voltages in the mirror bias circuit and the radio frequency (RF) amplifier. Thus, the tendency of the RF transistor quiescent current to decrease as Vcc decreases is off-set because the compensating resistors cause an increase in the RF transistor base-emitter voltage, thereby increasing quiescent current.

Abstract: A temperature compensated zero bias RF detector circuit includes a zero biased diode detector circuit feeding the positive input of a differential amplifier circuit. The negative input of the same differential amplifier circuit is a temperature compensation voltage. The temperature compensation voltage is produced by current flow from a bias source through a reference diode and through the resistor back to ground. The bias supply remains constant over temperature, whereas the temperature compensation voltage changes with temperature as the forward voltage across the reference diode changes with temperature. The differential amplifier outputs a temperature compensated detection voltage. The differential amplifier is followed by a voltage level shifter, which adjusts the output temperature compensated voltage to a suitable level for measuring equipment or for use by other processing circuits.

Abstract: Disclosed is a temperature compensation circuit for a power amplifier that is capable of stabilizing a variation in current of a bias circuit. The temperature compensation circuit comprises a bias voltage node for providing a bias voltage to the power amplifier; a regulated voltage node connected to a regulated voltage; a temperature sensor connected between the bias voltage node and a ground node, the temperature sensor having a resistance varying according to ambient temperature; a first resistor connected in parallel to the temperature sensor, for reducing a variation in resistance of the temperature sensor; and a second resistor connected between the regulated voltage node and the bias voltage node, for dividing the regulated voltage to generate the bias voltage.

Abstract: A temperature stable bias circuit for a radio frequency (RF) power amplifier uses current deletion and current supplement techniques to maintain the bias, or reference current of the RF power amplifier at a stable level regardless of the temperature that the power amplifier is operating. When temperature increases, the current deletion circuitry reduces the bias current supplied to the power transistor. When the temperature decreases, the current supplement circuitry increases the bias current supplied to the power transistor. This bias circuitry allows the output of the RF power amplifier to remain constant. The current deletion and current supplement circuitry can be fabricated using the same processing technology as the power amplifier and can be easily integrated into the power amplifier device packaging.

Abstract: Each radio of a plurality of radios includes a plurality of variable gain stages connected in series. The radio further includes at least one power detector connected to the variable gain stages, a temperature sensor, and a processor for controlling the variable gain stages in-service based upon the at least one power detector, the temperature sensor, and stored frequency and power compensation values. A method for calibrating each radio includes generating frequency compensation values for at least one first variable gain stage by supplying a first calibration signal swept in frequency while maintaining the radio at a constant temperature. The method further includes generating power compensation values for at least one second variable gain stage by supplying a second calibration signal swept in power level and while maintaining the radio receiver at a constant temperature.

Abstract: The low temperature-corrected constant voltage generator device includes a reference voltage generator, an amplifier connected between the reference voltage generator and an output terminal and a voltage divider connected to an input of the amplifier in order to supply a feedback voltage to the amplifier. The divider includes at least one first resistor in series with an element having, at least in the low temperature range, an impedance with a temperature dependence behavior different from that of the first resistor, to supply a lower feedback in the low temperature range.

Abstract: Disclosed is a cooling device of a linear power amplifier in a mobile communication system capable of continuously and repeatedly circulating a cooling water heat-exchanged at a low temperature in a base on which the linear power amplifier is mounted, thus to enable the heat transmitted to the whole liner power amplifier from a radio frequency transistor to be cooled by using the cooling water having a substantially higher coefficient of heat transfer than that of air. The cooling device includes a cooling water generating portion for generating a cooling water of a low temperature within an outer body of a base station transceiver subsystem, and a cooling portion for flowing the cooling water of the low temperature generated in the cooling water generating portion to the interior of a base on which the linear power amplifier is mounted, absorbing a surrounding heat to the cooling water of the low temperature, and then discharging the resulting water to the cooling water generating portion.

Abstract: A bias network uses resistive biasing, active biasing and current mirror biasing in combination to enhance RF power amplifier linearity and efficiency by forming a bias network that provides temperature compensation, minimizes current drain requirements for the Vbias source and reduces the level of RF linear amplifier quiescent current.

Abstract: A single transistor device is configured of a plurality of transistor cells divided and arranged in a plurality of blocks. Corresponding to the blocks a plurality of bias current supply circuits are arranged, respectively, to supply the blocks with individual bias currents, respectively. The bias current supply circuits each have a transistor with a bias condition set to decrease its ability to drive current as the corresponding bias current increases. Thus a negative feedback can be given to an increase in bias current attributed to thermal unevenness.

Abstract: Accuracy of correction of offset drift with temperature and noise are corrected in a high voltage, high current amplifier is improved by thermal isolation and/or temperature regulation of another amplifier having greater gain and connected to a different power supply in a closed loop feedback servo system. A clamping network connected to the higher gain amplifier to avoid hard saturation due to transient feedback signals from a reactive load, especially an inductive load, also prevents hard saturation of the high voltage, high current amplifier. An adjustable feedback circuit connected to the higher gain amplifier allows adjustment to obtain critical damping of a second order system and faster response to achieve proportionality of output current to input voltage with an accuracy of very few parts per million error and with minimum settling time.

Abstract: A method for suppressing distortion and removing selected signals from a feedback path in a closed-loop control system is provided. Improvements lie in the manner in which control signals for a vector controller are generated and in the addition of a reference network element which broadens effective cancellation bandwidth. Control signals for the vector controller are derived from various sensors which measure such parameters as temperature, signal level, distortion, etc. Sensor outputs are compared to those stored in a look-up table. Based upon this comparison, a processor decides which set of control signal values will yield improved cancellation of the selected signals. The bandwidth over which cancellation of the selected signals can be achieved is related to how closely the reference signal matches that of the selected signals in the feedback path. Match is controlled by passing the reference signal through a reference network which shapes its amplitude and/or phase.

Abstract: A bias network uses resistive biasing, active biasing and current mirror biasing in combination to enhance RF power amplifier linearity and efficiency by forming a bias network that provides temperature compensation, minimizes current drain requirements for the Vbias source and reduces the level of RF linear amplifier quiescent current.

Abstract: A bias network uses resistive biasing, active biasing and current mirror biasing in combination to enhance RF power amplifier linearity and efficiency by forming a bias network that provides temperature compensation, minimizes current drain requirements for the Vbias source and reduces the level of RF linear amplifier quiescent current.

Abstract: There is provided an AGC circuit with temperature compensation which has simplified a circuit configuration of a temperature compensation circuit unit and has reduced variation of gain characteristic of the stage to be controlled in its gain for variation of ambient temperature. This AGC circuit is composed of a signal detecting unit including a detection diode to generated a detected voltage in proportion to a signal level, a compensation voltage generating unit including a temperature compensation diode to generate a temperature compensation voltage and a differential amplifying unit forming an AGC voltage from a difference voltage of the detected voltage and temperature compensation voltage to supply the AGC voltage to the gain amplifying stage to be controlled.

Abstract: A temperature sensor has a first FET transistor circuit, whose operating point is located at the temperature-independent point, and a second FET transistor circuit whose operating point is above this point. The voltage difference in this case depends essentially linearly on the temperature. In addition, a circuit for controlling the gain of an amplifier circuit is provided, in which the current through the amplifier circuit at low temperatures is reduced by an appropriate control of the gate voltage of a transistor serving as a current source, so that an amplification which is substantially independent of temperature is carried out.

Abstract: A semiconductor device is provided having a high-frequency amplifying bipolar transistor (10) with its emitter electrode grounded. A current mirror circuit including a bipolar transistor (20) supplies the transistor (10) with a base potential as bias voltages for operating as a Class B or Class AB amplifier. A thermal linkage is established between the transistor (10) and the transistor (20) to reduce a difference between their junction temperatures. A metallic layer (4) is provided as a means for establishing the thermal linkage. The transistor (20) is provided between fingers (1A) and (1B) of the transistor (10) as another means for establishing the thermal linkage. A distance between the transistor (20) and one of the fingers (1A) and (1B) of the transistor (10) is made smaller than the thickness of a semiconductor substrate (7) on which the transistors are formed as other means for establishing the thermal linkage.

Abstract: Disclosed herein is a high frequency power amplifier system having a transistor comprised of a first electrode, a second electrode and a control electrode and for controlling current which flows between the first electrode and the second electrode by applying a potential to the control electrode, and a resistance type potential divider circuit for determining a dc bias potential applied to the control electrode of the transistor, and wherein an input signal is inputted to the control electrode, an output signal is outputted from the first electrode and a control signal is inputted to the resistance type potential divider circuit. One resistor of the resistance type potential divider circuit is comprised of a temperature compensating resistor whose resistance value varies linearly, so that a temperature characteristic of an idle current defined as an output when the control signal is not inputted, assumes a negative temperature characteristic.

Abstract: Disclosed is a compensation circuit for compensating a change in timing information of an input signal caused by thermal variations in a first circuit. The first circuit comprises one or more devices each having a temperature dependent on the input signal. Accordingly, the compensation circuit comprises one or more compensation devices each having a temperature dependent on the input signal. The compensation circuit is connected in series with the first circuit and the series connection receives the input signal and provides a timing-compensated output signal with substantially the same timing information as of the input signal. The thermal characteristic of at least one of the one or more compensation devices is proportional or in some other known relation to a corresponding one of the one or more devices of the first circuit. The compensation circuit provides a compensation output signal having substantially opposite or inverse thermal distortions than the first circuit.

Abstract: A bias network uses resistive biasing, active biasing and current mirror biasing in combination to enhance RF power amplifier linearity and efficiency by forming a bias network that provides temperature compensation, minimizes current drain requirements for the Vbias source and reduces the level of RF linear amplifier quiescent current.

Abstract: An amplifier output is biased to optimize performance characteristics such as gain and output voltage. A temperature-independent current is subtracted from a temperature-dependent current. The difference is injected at the amplifier output to bias the amplifier output such that performance characteristics are enhanced. An additional amplifier stage may be used to prevent the bandwidth performance of the amplifier from being affected by the current injection.

Abstract: A communication system (300) includes amplifiers (325) having an improved thermal response. The amplifiers (325) include a Bode circuit (208) for attenuating the signals and a thermal compensation circuit (320) for adjusting the gain in response to changes in temperature. The thermal compensation unit (320) provides a non-linear impedance to offset for the non-linear performance of the amplifiers gain versus control current. The thermal compensation unit (320) has circuit paths that are selectively turned on to provide the non-linear relationship of impedance versus input control voltage.

Abstract: A diode detector that is stable and linear over a wide range of variations in both temperature and power supply voltage and can be used to regulate a.c. signals produced by devices that are responsive to control signals includes a detector diode and a first resistor in series, a capacitor connected between the junction of first resistor and the detector diode and a reference potential, and a compensator diode and a second resistor in series with each other and with the detector diode and first resistor. An input a.c. signal is provided to a first terminal of the detector diode, and a rectified signal is provided at the junction of the detector diode, the first resistor, and the capacitor. The detector diode and the compensator diode have temperature coefficients that are substantially the same, and those diodes have the same polarities.

Abstract: An amplifier circuit containing at least one output stage transistor, a circuit for compensating for quiescent current drifts and optionally components for driving the output stage transistor. The circuit for compensating for quiescent current drifts has at least one reference current field-effect transistor with a gate electrode where the gate electrode is disposed in a region of the electrodes of the output stage transistor. Additionally, the reference current field-effect transistor is situated on a common chip area with the output stage transistor. Furthermore, the use of the above amplifier circuit in mobile radio systems is described.

Abstract: A linearized channel amplifier comprising a linear channel amplifier circuit 20 and a nonlinear linearizer circuit located immediately before a high power amplifier. A common control circuit controls the linear channel amplifier circuit and the nonlinear linearizer circuit. The linearized channel amplifier functions as a driver amplifier and improves the linearity and efficiency performance of the high power amplifier across a desired frequency bandwidth. The linearized channel amplifier employs low cost temperature compensation circuits in an interface circuit and a temperature compensation network circuit, and uses a novel methodology to provide for command and control functions that includes a measurement, analytical calculation and setting process. An external personality plug may be to set the performance of the channel amplifier and linearizer.

Abstract: An amplifier (125) having automatic gain control (AGC) includes a gain stage (220), having a variable amplifier (215), for amplifying a signal received by the amplifier (125). The amplifier (125) also includes an AGC circuit (228) that adjusts amplification of the gain stage (220) and that includes a manual switch (246) having first and second switch settings. Sequential operation from the first switch setting to the second switch setting causes the AGC circuit (228) to automatically and correctly set the gain of the amplifier (125) without further human intervention.

Abstract: An automatic gain control circuit having a plurality of receiving systems is structured to unify the receiving systems for performing level detection into one system and feedback data for controlling the gains of variable gain amplifiers 11a and 11b is subjected to correction of dispersion of the temperature characteristics between the variable gain amplifiers 11a and 11b of the receiving systems by operating a thermistor 31 so that a portion of an automatic gain control loop is made to be common without use of automatic gain control loops by the number corresponding to the number of the receiving systems.

Abstract: There is disclosed, for use in an RF amplifier, a biasing circuit for maintaining the quiescent current of an output power transistor at a selected bias level. The biasing circuit comprises a temperature sensor circuit for generating a temperature-sensitive control voltage that varies according to changes in temperature of the output power transistor and a bias voltage generating circuit capable of detecting a variation in the temperature-sensitive control voltage. In response to a detected change in the temperature-sensitive control voltage, the bias circuit adjusts a bias voltage applied to the output power transistor by an amount suitable to offset a change in the selected bias current level caused by a temperature change related to the variation in the temperature-sensitive voltage.

Abstract: A radio frequency (RF) power amplifier circuit comprising an RF gain stage formed on an integrated circuit (IC) chip comprising at least one field effect transistor configured for amplifying an RF signal to provide an amplified RF signal to an antenna at a given RF power level; a compensation circuit formed on the IC chip for generating a first voltage VS+ and a second voltage VS− at respective first and second output terminals, the voltage difference therebetween corresponding to a level of temperature or process fluctuation from a given level associated with the RF gain stage; and a control circuit comprising an operational amplifier coupled to the output terminals of the compensation circuit for receiving the first and second voltages VS+, VS− and outputting a control signal to the gate of the at least one FET of the RF gain stage to compensate the RF gain stage for the fluctuation, whereby a substantially constant power output to the antenna is maintained.

Abstract: An RF power amplifier has an RF driver stage that also provides a temperature independent reference current to the RF output power amplifier. A diode reference serves as both a DC current reference and as the first RF amplifier stage. Less DC power is consumed since no circuitry is used exclusively for establishing a DC reference.

Abstract: A circuit arrangement for amplifying a differential voltage signal in an output signal proportional to a voltage difference is provided, the voltages of a signal source that are to be compared being present at two inputs of the circuit arrangement, and a current signal proportional to the voltage difference being present at one output of the circuit arrangement, the circuit arrangement comprising cross-coupled transistors and the inputs being respectively connected to the base of one of the transistors, and a cross current of the circuit arrangement being present at the output. A compensation circuit is provided having a temperature behavior which corresponds to the temperature behavior of cross resistances of the circuit arrangement, the compensation circuit being associated with each of the inputs of the circuit arrangement.

Abstract: A high-frequency power amplifier has a high-frequency input, a high-frequency output and at least one power transistor connected therebetween. The power transistor has a first electrode serving as a control input, a cooling terminal connected to a second electrode and a third electrode. The third electrode is connected to a high-frequency reference potential conductor and the high-frequency reference potential conductor is connected in terms of high-frequency to the second electrode. An input signal applied to the high-frequency input is coupled out as an output signal at the high-frequency output.

Abstract: Compensating for fluctuations in the gain characteristic of the gain slope in the event of changes in ambient temperature without increasing circuit scale or adding to costs. A thermistor, which is a thermally sensitive resistance element in which resistance changes with a negative temperature characteristic according to the ambient temperature, is employed as the gate resistance of an FET, and the circuit functions such that fluctuations in the gain characteristic of the gain slope with respect to ambient temperature are canceled out by fluctuations in the value of Q with respect to the ambient temperature, thereby compensating for fluctuations in the gain slope characteristic in the event of changes in the ambient temperature.

Abstract: An amplifier for systems affected by changes in operating temperature, in which the amplifier gain is stabilized over temperature. A temperature compensating control element is added to the previously known active bias control amplifiers, forming a second control loop. This control acts to modify the device bias current, in a way which holds the device gain constant as temperature varies. In so doing it implements, in the circuit, the mathematically derived current variation which, based on the physics of the device, maintains constant gain. The additional circuitry is very inexpensive, preserving the cost-effectiveness of the integrated circuit bias scheme for those applications requiring the additional bias control.

Abstract: A precision GaAs low-voltage DC amplifier includes a level shift circuit, an amplifier and a first and a second bias control circuit. The level shift circuit shifts an input signal to generate a level shifted input signal, whose bias level is controlled by a first bias control voltage. The amplifier amplifies the level shifted input signal to generate an output signal. The bias level of the output signal is controlled by a second bias control voltage. The first bias control circuit insures that the first bias control voltage varies as necessary with temperature to hold constant the bias level of the level shifted input signal. The second bias control circuit insures that the second bias control voltage varies as necessary with temperature to hold constant the bias level of the output signal.

Abstract: A system that precisely controls the gain of an RF amplifier over varying temperatures. The system monitors the temperature of the RF amplifier and precisely controls the diode current in PIN diodes to precisely control the gain of the RF amplifier.

Abstract: An amplifier having an uncompensated gain which decreases with increasing temperature. The amplifier includes an integrated circuit chip having formed thereon a plurality of serially coupled amplifier stages. Each one of a portion of such stages has temperature compensation circuitry. Such circuitry includes a plurality of selectable gains, such gain being selected in accordance with temperature of the chip. The stage has a higher gain at a temperature above a predetermined threshold level associated with such stage and a lower gain at temperature below such predetermined threshold level associated with such stage. Each one of such stages is associated with a different predetermined threshold level. Each one of the stages includes a gain stage having a switchable feedback element, such stage providing a first gain when such element is switched into one state and a second gain when such element is switched into a second state.

Abstract: In a fully integrated logarithmic amplifier, an input current is fed via a diode, and in a reference current branch parallel thereto, a constant current flows through a similar diode. A voltage divider forms of the differential voltage between the two diodes a partial voltage on a variable resistor of the voltage divider, which is processed by a differential amplifier for forming the output signal. Parallel to the two current branches mentioned, there is provided an additional current branch having a constant current source and a diode. The differential voltage between the diode of the reference current branch and the diode in the additional current branch is also divided by a voltage divider. A differential amplifier forms of the voltage on the variable resistor of the voltage divider an error signal which changes the variable resistance from which the differential amplifier has formed the error signal as well as the resistance fo the variable resistor of which the output signal is formed.

Abstract: Apparatus, and an associated method, facilitates maintenance of ambient temperature levels within a radio base station cabinet above a minimum temperature level. During periods of low activity at a radio base station, signals are applied to a power amplifier of the transmitter portion of the radio base station. Thermal energy is generated as a byproduct of amplification of the signals provided thereto. The signals are selected such that the signals are rejected by filter circuitry, such as the duplexer filter circuitry, of the radio base station. Thereby, thermal energy is generated but amplified signals are prevented from being transmitted by the radio base station.

Abstract: A biasing and monitoring system for use with a circuit. The system comprises a biasing device, which is coupled to the circuit and which biases a circuit variable; and a monitoring device, which monitors a first indicator variable, and which comprises means for communicating information about the first indicator variable; and a controlling device. The controlling device controls the biasing device, receives information about the first indicator variable, is coupled to the biasing device and to the monitoring device, and comprises means for determining a desired value for the circuit variable.The system can be implemented in an amplifier system comprising a field effect transistor ("FET"). The system biases the gate voltage of the FET so as to minimize the intermodulation products for any given value of temperature. The system uses a look-up table to determine the proper biasing voltage, and desired source current, for any given temperature.

Abstract: A radio frequency amplifier having a power transistor (Q1) to the base of which is coupled a radio frequency signal to be amplified. An amplified radio frequency signal is provided at the collector of the power transistor (Q1). A control transistor (Qc) has its base coupled to the base of the power transistor (Q1) while a driver transistor (Q2) provides a control bias signal to the bases of the control and power transistors. A differential amplifier (Qd1, Qd2) has a first input coupled to an input bias signal and an output coupled to the base of the driver transistor (Q2). The collector of the control transistor (Qc) is coupled to a second input of the differential amplifier to provide a negative feedback signal to the differential amplifier and the driver transistor (Q2) and thereby to stabilise the operating point of the power transistor (Q1).

Abstract: An amplifier (125) includes a gain stage (210) for amplifying a signal, a variable attenuator (208), such as a Bode circuit, coupled to the gain stage (210) for attenuating the signal, and a signal level control circuit (222, 218, 220) coupled to the variable attenuator (208) and the gain stage (210) The signal level control circuit includes a thermal circuit (218) for measuring a temperature and a removable automatic gain control (AGC) circuit (220) for measuring signal level output by the gain stage (210). An adapter (222) coupled to the thermal circuit (218) and the removable AGC circuit (220) for controlling attenuation of the variable attenuator (208) in response to the temperature when the removable AGC circuit (220) is not electrically coupled to the gain stage (210) and in response to the signal level when the removable AGC circuit (220) is electrically coupled to the gain stage (210).

Abstract: An amplifier with a temperature compensation function featuring a simple configuration wherein a high frequency signal attenuation circuit is connected to a gate terminal of an amplifying active device. The high frequency signal attenuation circuit uses the source terminal and the drain terminal of a compensating active device as input and output terminals, and the gate terminal is grounded.

Abstract: A single bias block for a single or multiple low voltage RF circuits including one or more amplifiers and one or more single or double balanced mixers with compensation for temperature and integrated circuit process parameters. The power supply may be a lower voltage without sacrificing the dynamic range of the amplifier and/or mixer by applying full power supply voltage to the load with the bias applied to the base circuit through an operational amplifier and/or buffer circuit. For the mixer, a lower noise figure may also be realized by moving the gain control impedance from the emitter to the collector circuit. The circuits may be discrete components or part of an integrated circuit. Methods are disclosed for reducing the power supply voltage without affecting the dynamic range of an amplifier, for temperature and process parameter compensation, and for controlling the gain of a mixer without affecting input or output impedance.

Abstract: An automatic gain control circuit for a satellite communication transmitter, comprising a gain amplification circuit for amplifying an intermediate frequency signal from an output terminal of a modulator in the satellite communication transmitter, a distributor for distributing the amplified intermediate frequency signal from the gain amplification circuit, an intermediate frequency signal detector for detecting the intermediate frequency signal distributed by the distributor, a reference signal detector for detecting a reference signal from an indoor system controller, the reference signal being used to control a level of the intermediate frequency signal distributed by the distributor, and a differential integrator for offsetting variations in an output signal from the intermediate frequency signal detector and in an output signal from the reference signal detector based on external temperature variations with respect to each other and feeding the resultant signal back to the gain amplification circuit.

Abstract: A power amplifier circuit is provided which comprises an input terminal for receiving an input signal and an output terminal for providing an output signal, and at least one transistor for amplifying the input signal to provide the output signal, and a module for controlling the input signal received at the input terminal, and a module for generating a control signal which substantially follows the temperature of the at least one transistor at least in a selected temperature range. The module for controlling the input signal controls the input signal such that the control signal is prevented from exceeding a pre-determined level. The level corresponds to a pre-determined temperature of the at least one transistor which is equal to or below a specified maximum temperature for the at least one transistor.