Abstract: According to an embodiment, a method includes amplifying a signal provided by a capacitive signal source to form an amplified signal, detecting a peak voltage of the amplified signal, and adjusting a controllable impedance coupled to an output of the capacitive signal source in response to detecting the peak voltage. The controllable impedance is adjusted to a value inversely proportional to the detected peak voltage.

Abstract: An automatic step variable attenuator includes: a step variable attenuator attenuating a received signal of an electric wave signal in an attenuation amount corresponding to a control signal in a step-like style; a detector disposed in parallel with the step variable attenuator for input of the received signal of the electric wave signal, and converting an electric power of the received signal thus inputted into an intensity signal representing an intensity of the received signal; and a comparator portion generating the control signal corresponding to a result of comparison for differences between the intensity signal obtained from the detector and plural threshold values, and outputting the control signal thus generated to the step variable attenuator.

Abstract: A variable gain amplifier circuit includes: an operational amplifier having a non-inverting input terminal applied with a predetermined voltage; a feedback resistor having one end connected to an inverting input terminal of the operational amplifier and the other end connected to an output terminal of the operational amplifier; and a variable resistor having one end applied with an input voltage and the other end connected to the inverting input terminal of the operational amplifier.

Abstract: An output buffer circuit capable of enhancing stability includes an operational amplifier, a capacitive load and an output control unit. The operational amplifier has a positive input terminal, a negative input terminal and an output terminal, and generates an output voltage to the output terminal according to an input voltage received by the positive input terminal. The output control unit is coupled between the output terminal of the operational amplifier and the capacitive load, and is utilized for controlling electrical connection between the output terminal of the operational amplifier and the capacitive load to form a signal output path and for adjusting impedance of the signal output path when the signal output path is formed.

Abstract: An apparatus and method for amplifying a transmission signals in multiple modes and multiple bands. The apparatus includes a tunable power amplifying module adapted to receive a plurality of signal types comprising multiple modes and multiple bands. The tunable power amplifying module includes a first and second power amplifier stages and a number of tunable matching networks configured to optimize an impedance value based on the mode and band of the signal to be amplified.

Abstract: The embodiments disclosed in the detailed description include a power amplifier having a low power mode amplifier, a medium power mode amplifier, and a high power mode amplifier in communication with a radio frequency (RF) output load. The exemplary embodiments of the power amplifier permit a wireless device to select the most power efficient means to transmit an RF signal based upon the desired output power level.

Abstract: An amplifier for electric guitar including a Cut control for attenuating high frequencies whose operation is expanded via a switch to alternately function as a Master Volume control.

Abstract: A device includes a matching stage coupled between a first signal terminal and a second signal terminal. A signal path extends between the first signal terminal and the second terminal. An adjustable impedance element is connected to the signal path. A detection circuit is coupled to the signal path and configured to derive matching information. A control circuit is coupled between the detection circuit and the adjustable impedance element. The control circuit is configured to control the adjustable impedance element.

Abstract: A transceiver includes a harmonic termination circuit that receives a tunable harmonic voltage from a power amplifier control. The harmonic termination circuit includes a variable capacitor that is capable of adjusting its capacitance in response to the tunable harmonic termination voltage to achieve at least two modes of operation. The at least two modes of operation may be EDGE mode and GSM mode. In this embodiment, the harmonic termination circuit allows for linearity specifications of EDGE to be met, while not degrading the efficiency of the transceiver when operating in GSM mode. In one embodiment, the harmonic termination circuit further includes an inductive element in series with the variable capacitor.

Abstract: In a method and apparatus for compensating for gain changes in an amplifier circuit comprising radio-frequency modules and attenuation elements, a radio-frequency module is driven with a first temperature-dependent monitoring voltage UHF(T), and an attenuation element with a second temperature-dependent monitoring voltage UVG(T). The first temperature-dependent monitoring voltage UHF(T) is produced by applying a temperature dependency to an individual monitoring voltage Uopt, which is predetermined for a predetermined temperature for a radio-frequency module, in order to set the optimum operating point of the radio-frequency module. The second temperature-dependent monitoring voltage UVG(T) is produced by applying a temperature dependency to a predetermined monitoring voltage UVG—T for the attenuation element. The monitoring voltage UVG—T is determined in an iteration method, such that the output power of the amplifier circuit reaches a predeterminable level at a constant input power.

Abstract: A calibration unit calibrates a power amplifier load impedance to achieve a nominal amplifier load impedance after the connection of one or more external elements, e.g., antenna, to improve the accuracy and effectiveness of output power calibration. The calibration unit comprises an adaptive impedance unit and a controller. The adaptive impedance unit includes first and second variable impedance elements connected between the amplifier and the external load, e.g., antenna. The controller independently calibrates the imaginary and real parts of the load impedance by respectively selecting first and second calibration values for the first and second variable impedance elements based on a reference voltage. More particularly, the controller selects calibration values for the first and second variable impedance elements from a plurality of impedance values based on a comparison between a reference voltage and the calibrated voltages produced at the output of the power amplifier responsive to the impedance values.

Abstract: An input stage for an instrumentation system may include a resistor coupled between an input terminal and a summing node, and an amplifier arranged to maintain the voltage at the summing node. In anther embodiment, an instrumentation input system may include an input stage to receive a signal to be measured, and a variable gain amplifier having an input coupled to an output of the input stage, wherein the variable gain amplifier comprises two or more gain stages. A variable gain amplifier may include an attenuator having an input and a series of tap points and a series of low-inertia switches to steer outputs from the attenuator to an output terminal.

Abstract: An apparatus and a method for preventing transmission degradation in a mobile terminal. The apparatus includes an antenna, a Power Amplifier Module (PAM), and a matching module. The PAM amplifies power of a transmission signal. A matching module is located between the antenna and the PAM, to match impedance of a signal whose power is amplified by the PAM using a matching value determined depending on a supplied power magnitude of the PAM.

Abstract: A circuit and method for automatic level control is provided. The circuit includes an amplifier including a variable resistance circuit that is connected between a first node and a second node. The circuit also includes a first resistance circuit that is connected between a first input node and the first node, and a second resistance circuit that is connected between the first input node and a first op amp node. The first and second resistance circuits are at least approximately linear elements. The circuit also includes an op amp having at least a first input that is connected to the first op amp input node.

Abstract: A low noise amplifier includes an input transistor, an inductor, and a current sink. The input transistor includes a gate, a drain, and a source, wherein the gate of the input transistor is operably coupled to receive an input radio frequency (RF) signal. The inductor includes a first node and a second node, wherein the first node of the inductor is operably coupled to a power supply and the second node of the inductor is operably coupled to the drain of the input transistor to provide an output of the low noise amplifier. The current sink includes a first node and a second node, wherein the first node of the current sink is operably coupled to the source of the input transistor and the second node of the current sink is operably coupled to a circuit ground, wherein a real component of input impedance of the low noise amplifier is substantially constant when the low noise amplifier is in the off mode as when the low noise amplifier is in the on mode.

Abstract: Audio amplifiers are used in many known forms in music systems, for example for domestic use or for playing music in cinemas, discos etc., but also in public address systems, as are known, for example, in public buildings, schools, universities etc. for making announcements. The invention proposes an audio amplifier (1) for amplifying an input signal into an output signal using an output amplifier stage (6), wherein the output amplifier stage (6) is designed to amplify an intermediate signal into the output signal, and wherein the output amplifier stage (6) is in the form of an amplifier which operates in switching mode, and having a limiter device (4) which is designed, from a program and/or circuit point of view, to generate the intermediate signal on the basis of the input signal, wherein the level of the intermediate signal is always limited as a function of an adjustable maximum level in such a way that the output signal does not exceed the maximum level independently of the input signal.

Abstract: Disclosed herein is a dual band high frequency amplifier using a composite right/left handed (CRLH) transmission line (TL). Accordingly, a CRLH TL structure having a dual band characteristic is inserted into an input matching circuit and/or an output matching circuit in the high frequency amplifier, and a matching circuit is designed so that impedance matching is performed at two frequencies, thereby obtaining both gain and matching characteristics at the two frequencies.

Abstract: A high-frequency amplifier includes: an amplification section having a function to convert an input signal from a voltage signal into a current signal and output the current signal; output terminals; and a load circuit which is connected to the output node of the amplification section and outputs the current signal output by the amplification section to the output terminals as a voltage signal.

Abstract: A radio frequency (RF) amplifier circuit includes a first impedance matching circuit configured to receive an input RF signal, a control circuit configured to produce a band control signal according to the frequency of the input RF signal, an RF amplifier having its input connected to the first impedance matching circuit. The RF amplifier can produce an amplified RF signal in response to the input RF signal. A second impedance matching circuit can receive the amplified RF signal from the RF amplifier. At least one of the first impedance matching circuit and the second impedance matching circuit has an impedance that is adjustable by the band control signal. A multi-band filter can switch the amplified RF signal from the second impedance matching circuit to one of selectable narrow-band filters in response to the band control signal.

Abstract: A voltage-to-current converter is provided. The voltage-to-current converter comprises an amplifier, a resistor network, an R-2R network, and switches. The amplifier has a first input node (which is an input signal), a second input node, and an output node. The resistor network is coupled to the output node of the amplifier, includes a plurality of resistors coupled in series with on another, and includes a plurality of first tap nodes. The R-2R network is coupled to the resistor network and includes a plurality of second tap nodes. Additionally, at least one switch is coupled between the second input node of the amplifier and each first tap node, and at least one switch is coupled between the second input node of the amplifier and each of the second tap nodes.

Abstract: There is disclosed a variable-gain amplifier circuit that operates on a low voltage, exhibits low distortion, provides a wide range of variation, and is suitable for use in a low-power-consumption wireless communication system. The variable-gain amplifier circuit is configured so that a variable-load circuit, which includes three reactance function elements and provides a wide range of impedance variation, is connected to a conductor circuit whose output terminal generates a positive-phase output current proportional to conductance with respect to an input voltage.

Abstract: The invention relates to a circuit for adjusting an impedance between two terminals, said impendance including the input impedance of the circuit. The aim of the invention is to enlarge the adjustment range and to stabilize—the operating behavior of such a circuit. For this purpose, the circuit comprises amplifiers, adjusting means with which amplification of at least one amplifier and/or the circuit can be changed in general and the impedance between the two terminals can be modified by influencing the one or more adjusting means.

Abstract: A control circuit includes an operational amplifier having an inverting input, a non-inverting input, and an output, an array of impedance elements including capacitors are connected to the output of the operational amplifier, and a resistance switch crossbar array configured to store data in the form of high or low resistance states, wherein the resistance switch crossbar array is electrically connected between the array of impedance elements and the inverting input of the operational amplifier. The crossbar control circuit may be implemented in a control system to provide for adjustment of the control system to changes in environmental conditions or to change the function of the control system.

Abstract: Systems and methods are disclosed for a device having one or more power amplifier and/or LNA circuits positioned on the amplifier module.

Abstract: In an amplifier including first and second power supply terminals, first and second output terminals, a first load connected between the first power supply terminal and the first output terminal, a second load connected between the first power supply terminal and the second output terminal, a constant current source connected to the second power supply terminal, a first transistor connected between the first output terminal and the constant current source, a control terminal of the first transistor being adapted to receive an input voltage, and a second transistor connected between the second output terminal and the constant current source, a control terminal of the second transistor being adapted to receive a reference voltage, an amplification and output impedance switching circuit is connected between the first and second output terminals, so that the amplifier and output impedance switching circuit controls an amplification and output impedance of the amplifier in accordance with a control signal.

Abstract: A method and apparatus for selecting and mixing electronic signals. The circuit has an operational amplifier and two or more ganged, tapped-resistors in which the tap divides the resistance into a first and a second resistance. The tapped-resistors are connected so that either the first or the second resistance provides the effective input resistance for that signal at the operational amplifier. The second resistance of one of the tapped-resistors provides the output resistance for all signals at operational amplifier. As the tapped resistors are equivalent and their taps ganged, when the signals are mixed, those signals whose effective input resistance at the operational amplifier is selected to be the second resistance have unit gain, while those signals whose effective input resistance at the operational amplifier is selected to be the first resistance have a gain equal to the second resistance divide by the first resistance.

Abstract: A gain controlled amplifier and a cascoded gain controlled amplifier based on the same are disclosed. The gain controlled amplifier includes an operational amplifier for amplifying an input signal, an input resistor connected to an input terminal of the operational amplifier, a feedback resistor connected to an output terminal of the operational amplifier, and a resistor circuit for providing voltages having different levels to the input terminal and the output terminal of the operational amplifier, respectively, according to a digital signal composed of specified bits. The gain controlled amplifier employs an R-2R ladder circuit controlled by a digital signal so as to obtain a gain that is in linear proportion to a decibel scale. Since the R-2R ladder circuit operates with a small resistance value, the chip size of the gain controlled amplifier can be reduced.

Abstract: A millimetric-wave amplifier arrangement comprises a first amplifier whose output is connected to one input of the second amplifier via an adjustable attenuator. Both amplifiers are integrated on a single substrate.

Abstract: For a first transistor, a source thereof is coupled to an input terminal and a drain thereof is coupled to an output terminal. A first variable impedance circuit is arranged between a gate of the first transistor and ground, and the impedance thereof is changed according to a first control signal. A second variable impedance circuit is arranged between the gate and the source of the first transistor, and the impedance thereof is changed according to a second control signal. Furthermore, an impedance circuit is arranged between the gate of the first transistor and a power supply. The ratio of the impedances of the first and second variable impedance circuits can be set to an arbitrary value according to the first and second control signals in order to change the gain of the low noise amplifier. As the result, the generation of unwanted thermal noise can be prevented.

Abstract: A system for controlling gain in a polar loop is disclosed. Embodiments of the invention provide for a substantially constant gain tolerant of changes in supply voltage, ambient temperature, and/or manufacturing process.

Abstract: In a third operation in an amplifier, in which first and second amplifier circuits amplify a input signal, a distribution circuit adjusts the power of the signal supplied to the first amplifier circuit to within a range in which the input power to the first amplifier circuit and the output power from the first amplifier are proportional to each other. In a linear operation, the power of the signal from the first amplifier circuit and input to the comparison circuit and the power of the signal from the second amplifier circuit and input to the comparison circuit are equal. The comparison circuit adjusts the gain or the saturated power of the second amplifier circuit on the basis of the difference between the signals from the first and second amplifier circuits and input to the comparison circuit, so that the input power to the second amplifier circuit and the output power from the second amplifier circuit are proportional to each other.

Abstract: This variable gain amplifier is provided with an operational amplifier. The non-inversion input terminal of the operational amplifier is connected to a reference potential. A feedback resistor is connected between the output terminal and inversion input terminal of the operational amplifier. An input resistor is inserted between the inversion input terminal of the operational amplifier and the input terminal of the variable gain amplifier circuit. An adjustment resistor is connected between the inversion input terminal of the operational amplifier and the reference potential. The resistance value of the adjustment resistor is controlled in such a way as to maintain constant against the resistance value change a combined resistance value in its parallel connection with the input resistor when changing the resistance value of the input resistor.

Abstract: An Integrated Circuits (ICs) comprising a first output stage circuit and a second output stage circuit that share common input terminals and an output terminal of the first and second output stage circuits being selectably coupled between the input terminals and the output terminal in preference to the other.

Abstract: Circuitry to remove switches from signal paths in integrated circuit programmable gain attenuators. Programmable gain attenuators and programmable gain amplifiers commonly switch between signal levels using semi-conductor switches. Such switches may introduce non-linearities in the signal. By isolating the switches from the signal path linearity of the PGA can be improved.

Abstract: A dB-linear variable gain amplifier, a method for creation, and a system includes an amplifier; a pair of resistor arrays operatively connected to the amplifier, wherein each resistor array comprises MOS transistor resistive switches; a differential ramp-generator circuit operatively connected to the pair of resistor arrays; and voltage control lines generated by the differential ramp-generator circuit, wherein the voltage control lines are operatively connected to each of the MOS transistor resistive switches in the pair of resistor arrays. The number of the voltage control lines that are operatively connected to the each of the MOS transistor resistive switches is equal to the number of resistors in a particular resistor array. The differential ramp-generator circuit is preferably operable to take an automatic gain control voltage and generate a series of differential ramp voltages and apply the series of differential ramp voltages to one of the MOS transistor resistive switches.

Abstract: Provided are input-gain control apparatus and method of an audio amplifier. A gain of an acoustic signal is automatically attenuated based on a pre-set limited level to minimize distortion of the acoustic signal caused by clipping of the acoustic signal, and thereby limit an over-input of the acoustic signal to input the acoustic signal within a dynamic range if the acoustic signal is not input within the dynamic range in an audio apparatus including an acoustic amplifier and a switching amplifier. Thus, only a gain of an over-input signal on a specific level or more can be attenuated while an original form of the over-input signal is maintained to minimize distortion of an output waveform caused by clipping of the output waveform. Also, a harmonic distortion and a stepped high frequency noise occurring during clipping can be simultaneously removed.

Abstract: The present invention relates to a method and an arrangement for optimizing the efficiency of a power amplifier (1) that is utilized for transmission of radio signals in a portable radio communication device, such as a mobile phone. The impedance loading the power amplifier (1) is controlled by a controller (5) in dependence on a transmission power of the portable radio communication device, wherein the radiating impedance of an antenna element (2) loading the power amplifier is controlled in dependence of the desired load impedance. Preferably, the changing of radiating impedance is performed by changing a capacitive coupling between the antenna element and a ground element or by changing the size of the antenna element. Better efficiency and bandwidth are thereby attained.

Abstract: A high power amplifier having high efficiency, compact and low cost characteristics based on the simple circuit structure effectively used over a wide range of the output power. A control circuit controls power supply operations of the power supply unit such that a high power amplifying unit can act as a low loss resistor that does not amplify the input signal during low power operation of the amplifier, but the high power amplifying unit amplifies the input signal during high power operation.

Abstract: A non-linearity generator operates on a signal between a frequency converter and an amplifier and acts as a postdistorter for the component it follows and as a predistorter for the component it precedes, thus linearizing the overall input-output characteristic of the circuit. Cross-modulation components distorting an injected pilot signal provide a feed-back signal that is used to control the distortion applied by a non-linearity generator. The non-linearity generator can be adapted to cope with widely spaced input tones. The circuit may form part of a transmitter or a receiver.

Abstract: An operational amplifier circuit includes an operational amplifier, an intermediate circuitry, and a control circuitry. The intermediate circuitry is coupled to a load. The operational amplifier is coupled to the intermediate circuitry and drives the load through the intermediate circuitry according to an input signal. The control circuitry is coupled to the intermediate circuitry and controls the intermediate circuitry to adjust an equivalent loading induced by the intermediate circuitry.

Abstract: An amplifier output voltage swing extender circuit comprises a differential amplifier powered between first and second power supply rails, which receives first and second input signals at non-inverting and inverting inputs, respectively, and provides an output at a first output node. A level shifting circuit, preferably a voltage divider, is connected in series with the first output node and shifts the node voltage toward the second rail by a fixed amount; the shifted voltage is provided at a second output node. A feedback network couples the second output node voltage to the amplifier's inverting input, such that when a voltage VSET is applied to the non-inverting input, the maximum negative voltage excursion at the first and second output nodes is greater than the value of the VSET voltage with respect to the second supply rail.

Abstract: A first FET is inserted in a series position between a signal input terminal and a signal output terminal, while second and third FETs are inserted in a shunt position respectively between the signal input terminal and a ground terminal and between the signal output terminal and a ground terminal. First and second reference voltage terminals and a control terminal are provided. A first reference voltage and a control voltage are applied to the first FET, while a second reference voltage and a control voltage are applied respectively to the second and third FETs, so that the first, second, and third FETs serve as variable resistors. As such, a gain control circuit is constructed. Further, a first resistor is provided in parallel to the first FET, while second and third resistors are provided respectively in series to the second and third FETs.

Abstract: A self-tuning variable impedance circuit provides improved performance. A variation in the power applied to the variable impedance circuit causes a corresponding change in the impedance of the circuit, resulting in improved performance. For example, the variable impedance circuit may be a matching circuit that “follows” the output power of a power amplifier, thereby increasing the power efficiency of the power amplifier.

Abstract: Power amplifiers are disclosed that demonstrate improved linearity and efficiency in applications requiring significant peak-to-average ratios (PAR). A power amplifier in accordance with the present invention comprises a first transistor in an input stage that converts DC power into AC power; and a second transistor in a negative conductance stage that has a current-voltage characteristic with at least two slopes. The at least two slopes of the current-voltage characteristic are separated by a break point that may be controlled. The power amplifier may also include a non-dissipative two-port device that has two AC ports. The non-dissipative two-port device has a Z matrix with two zero-valued diagonal elements and two complex valued off-diagonal elements having a same sign and only imaginary parts for an operating frequency. In one implementation, the diagonal entries of the Z matrix are small at twice the operating frequency.

Abstract: A low noise amplifier includes an input transistor, an inductor, and a current sink. The input transistor includes a gate, a drain, and a source, wherein the gate of the input transistor is operably coupled to receive an input radio frequency (RF) signal. The inductor includes a first node and a second node, wherein the first node of the inductor is operably coupled to a power supply and the second node of the inductor is operably coupled to the drain of the input transistor to provide an output of the low noise amplifier. The current sink includes a first node and a second node, wherein the first node of the current sink is operably coupled to the source of the input transistor and the second node of the current sink is operably coupled to a circuit ground, wherein a real component of input impedance of the low noise amplifier is substantially constant when the low noise amplifier is in the off mode as when the low noise amplifier is in the on mode.

Abstract: A feed-forward operational amplifier including a dedicated summer circuit for summing a signal generated by a first amplifier stage of a feed-forward amplifier and a signal received from an external source to generate a sum signal and a second amplifier stage coupled to the summer circuit and receiving the sum signal. The second amplifier stage realizes a pole-zero doublet to decrease a unity gain frequency of the feed-forward operational amplifier.

Abstract: A device for amplifying or attenuating HF signals is characterized in that a transistor is connected in a common-emitter configuration in amplifying operation, and a base-collector diode is connected in the forward-biased direction for attenuating operation.

Abstract: Circuitry is provided that conditions a differential input signal such that when the signal is received by a multi-standard differential input buffer, the buffer is able to process the conditioned signal without pronounced increases in propagation delay, thereby keeping signal jitter to a minimum. The circuitry further enables input buffers to operate according to desired operating parameters even when the supply voltage powering the input buffer is relatively low. The circuitry operates by shifting the common-mode voltage to a range that puts the input buffer in a favorable common-mode voltage range of operation. The circuitry may be coupled with a programmably controlled amplifier that amplifies the amplitude of the conditioned differential signal prior to being received by the input buffer. Amplifying the signal prevents problems typically associated with data-dependent jitter and intersymbol interference by boosting the voltage amplitude to a level that is readily processed by the input buffer.

Abstract: A method and an arrangement for detecting impedance mismatch between an output of a radio frequency amplifier (200, 901, 911, 921, 1101) which has an amplifying component (201, 301, Q46, 701, 801) and an input of a load (203, 302) coupled to the output of the radio frequency amplifier having: first monitoring means (401) to monitor a measurable electric effect (311) at a side of the amplifying component (201, 301, Q46, 701, 801) other than the load (203, 302) and to produce a first measurement signal (411). Second monitoring means (402) monitor a measurable electric effect (312) between the amplifying component (201, 301, Q46, 701, 801) and the load (203, 302) and produce a second measurement signal (412). Decision-making means (204, 902, 912, 923, 1102) receive said first (411) and second (412) measurement signals and decide, whether said first and second measurement signals together indicate impedance mismatch.

Abstract: A programable gain amplifier (PGA) has an amplifier and a variable resistor that is connected to the output of the amplifier. The variable resistor includes a resistor that is connected to a reference voltage and multiple parallel taps that tap off the resistor. A two-stage switch network having fine stage switches and coarse stage switches connects the resistor taps to an output node of the PGA. The taps and corresponding fine stage switches are arranged into two or more groups, where each group has n-number of fine stage switches and corresponding taps. One terminal of each fine stage switch is connected to the corresponding resistor tap, and the other terminal is connected to an output terminal for the corresponding group. The coarse stage switches select from among the groups of fine stage switches, and connect to the output of the PGA.