Abstract: Aspects provide for the broadband amplification of RF signals. Other aspects provide for the conversion of single ended input to differential output. Various aspects provide for tuning the response to a particular frequency band. Other aspects provide for various transconductance elements. In several aspects, broadband current to voltage converters and voltage to current converters are presented. Some implementations incorporate a buffer circuit, and various implementations incorporate feedback circuits.

Abstract: In a broadband low-noise amplifier circuit to be used in a multichannel reception system, a capacitance of a variable capacitor (9) is controlled by a resonance frequency control circuit (4) so that a resonance frequency of a load unit (2) comprising the variable capacitor (9) and an inductor (10) matches a desired RF signal frequency. Therefore, high gain and broadband can be realized at the same time without increasing power consumption, and consequently, a reception system having reduced power consumption and high sensitivity for all channels can be realized.

Abstract: A variable gain amplification circuit comprises a signal generator that has an output terminal and is able to vary an output amplitude; a variable capacitor connected between the output terminal and an AC grounded terminal; and a control circuit for controlling the output amplitude of the signal generator, and a capacitance of the variable capacitor. Therefore, unnecessary signals can be attenuated even when the gain is low, and degradation in distortion characteristics in the latter block can be suppressed.

Abstract: Embodiments of a high-linearity low-noise amplifier (LNA) are generally described herein. Other embodiments may be described and claimed. In some embodiments, an RF input signal may be amplified with a cascode amplifier. The cascode amplifier may include integrated notch filters to attenuate undesired signals. The cascode amplifier may operate from a large power supply when blockers are present to avoid voltage swing compression at its output. The cascode amplifier may be biased and designed to operate in a class AB mode to produce linear output current to avoid current compression or excessive current expansion.

Abstract: Aspects provide for the broadband amplification of RF signals. Other aspects provide for the conversion of single ended input to differential output. Various aspects provide for tuning the response to a particular frequency band. Other aspects provide for various transconductance elements. In several aspects, broadband current to voltage converters and voltage to current converters are presented. Some implementations incorporate a buffer circuit, and various implementations incorporate feedback circuits.

Abstract: A multi-band, multi-standard programmable power amplifier having tunable impedance matching input and output networks and programmable device characteristics. The impedance of either or both of the impedance matching input and output networks is tunable responsive to one or more control signals. In one example, the programmable power amplifier incorporates a feedback control loop and the control signal(s) are varied responsive to the feedback loop.

Abstract: A buffer varies the size of its output stage in response to a varying capacitive load. The capacitive load may vary in a predictable or a random manner. The buffer includes an operational amplifier having an output stage of multiple transistors, selectively connected in parallel. During operation, data regarding the size of the capacitive load is obtained and used to determine the size of the output stage. In general, as the capacitive load increases, the number of transistors connected in parallel at the output stage also increases.

Abstract: A dual reactive shunt feedback low noise amplifier design may include a transconductance amplifier having a capacitor coupled across it and a pair of coupled inductors coupled across it. In one embodiment, the coupled inductors may be laid out as two overlapping coils.

Abstract: The present invention relates to amplifier bias circuitry, which provides a direct current (DC) bias to a radio frequency (RF) amplifier. The amplifier bias circuitry includes a control loop having a control loop bandwidth, and an output impedance associated with providing the DC bias to the RF amplifier. The amplifier bias circuitry may vary the DC bias, the output impedance, the control loop bandwidth, or any combination thereof, to meet wireless communications requirements. For example, in a multi-mode radio, low output impedance may be needed to meet linearity requirements of the RF amplifier associated with wireless communications protocols in one mode of the multi-modes; however, some low output impedance designs may reduce the control loop bandwidth below that needed to meet modulation requirements associated with wireless communications protocols in another mode of the multi-modes.

Abstract: A method for changing an effective capacitance of an amplifier circuit having a match transistor and a coupled cascode transistor includes changing an on-state of at least one of a plurality of sub-transistors of the match transistor. The method further includes changing a transconductance of the match transistor as a function of the change of the on-state. The method further includes changing an equivalent resistance, as measured between a source and a drain of the cascode transistor, as a function of the change of the transconductance of the match transistor.

Abstract: A variable frequency amplifier suffering less deterioration of strain characteristic and capable of operating at plural frequencies is disclosed. In one aspect, a changeable amplifier comprises an amplifying element, a changeable matching circuit disposed at an input side of the amplifying element and including a first variable capacity element connected in series with a signal conductor and a second variable capacity element connected in parallel with the signal conductor, and a control circuit for controlling the changeable matching circuit. Based on a feedback signal, the control circuit applies DC bias voltages to the first variable capacity element and the second variable capacity element of the changeable matching circuit and also applies thereto a correction signal.

Abstract: Aspects of the disclosure can provide a bandpass transconductance amplifier that can include a minuend transconductance amplifier that converts a voltage signal to a first current and a subtrahend transconductance amplifier that converts the voltage signal to a second current having substantially the same amplitude as the first current but opposite polarity in both a first and a second stopband. The second current can have a substantially smaller amplitude than the first current in a passband. The disclosed bandpass transconductance amplifier can also include a controller that can tune the passband and the stopbands and a summing circuit that can add the first current and the second current.

Abstract: An electronic device includes a nonlinear power amplifier, a predistortion coefficient calculator, and a memory polynomial predistortion filter coupled to the nonlinear power amplifier and to the predistortion coefficient calculator. The memory polynomial predistortion filter may include a plurality of finite impulse response (FIR) filter stages, and a summer coupled to the plurality of FIR filter stages. The FIR filter stages may functionally operate in parallel or may include a series of FIR filters coupled in parallel.

Abstract: A wireless transceiver system for compensating a transport loss includes a transceiver (100), a tower mounted amplifier (TMA) (200), and a transport loss detector (400). The transceiver transmits a first signal at a transmit power. The first signal is changed into a second signal after cable attenuation from the transceiver. The TMA is connected to the transceiver via a cable, receives a second signal, and amplifies the second signal. The transport loss detector is connected to the TMA, and calculates a transport loss between the transceiver and the TMA. The TMA further compensates the transport loss between the transceiver and the TMA according to the calculated result of the controller.

Abstract: A wireless transceiver system, for compensating a transport loss, includes an antenna (300), a transceiver (100), a tower mounted amplifier (TMA) (200), and a transport loss detector (400). The transceiver transmits a first signal at a transmit power. The first signal is changed into a second signal after the cable attenuation from the transceiver. The TMA, connected to the transceiver via a cable, receives the second signal and amplifies the second signal. The transport loss detector, connected between the TMA and the transceiver, detects a transmission state of the transceiver, and calculates a transport loss between the transceiver and the TMA. The TMA transmits signals to the antenna or receives signals from the antenna according to the detected result of the transport loss detector, and compensates the transport loss according to the calculated result of the transport loss detector.

Abstract: A radio frequency (RF) application circuit is provided. In the RF application circuit, a pair of bipolar junction transistors (BJTs), instead of N-channel metal-oxide-semiconductor (NMOS) transistors, is composed of a switch-block operated in a reversion saturation region. The RF application circuit is used to serve as either an oscillator or a band pass amplifier according to the circuit characteristic of an active circuit. Thereby, not only the function of the conventional NMOS transistor served as a switch can be achieved by the switch-block, but also the element size, turned-on resistance value and turned-off parasitic capacitance value of the switch-block, and the power consumption of the RF application circuit thereof can be reduced. Thus, the resolution of the capacitance unit in a LC resonance circuit and the performance of the RF application circuit thereof can be promoted.

Abstract: Example embodiments of the invention may provide for active baluns. An example active balun may include a resonator that may convert a single-ended input signal to at least two differential input signals, and a differential switching block that includes first and second transistors that each receive a respective one of the at least two differential input signals from the resonator, where the first and second transistors may be cross-coupled to each other to provide a first differential output signal and a second differential output signal. An example active balun may further include one or more loads connected to the first and second differential output signals, and one or more stacked inverters that may provide a first output port and a second output port, where the first output port may be responsive to the first differential output signal and the second output port may be responsive to the second differential output signal.

Abstract: Systems and method for tracking different types of transconductance cells is shown and described. In these multi-cell systems, the addition of one or more tracking control modules allows circuit designers to advantageously incorporate multiple transconductor topologies and their uniquely beneficial characteristics into their designs, without eradicating its centralized multi-cell tuning functionality.

Abstract: Circuits and methods are provided for building integrated transformer-coupled amplifiers with on-chip transformers that are designed to resonate or otherwise tune parasitic capacitances to achieve frequency tuning of amplifiers at millimeter wave operating frequencies.

Abstract: A circuit having: an input matching network; a transistor coupled to an output of the input matching network; and wherein the input matching network has a first input impedance when such input matching network is fed with an input signal having a relatively low power level and wherein the input matching network has an input impedance different from the first input impedance when such input matching network is fed with an input signal having a relatively high power level.

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 novel and useful load compensation circuit and associated pre-power amplifier constructed therefrom. The load compensation circuit functions to maintain a nearly constant output impedance of the pre-power amplifier by use of a switch matrix comprising a plurality of transistors. The switch matrix is placed in parallel with the output of the pre-power amplifier (PPA). Transistors are turned on or off within the load compensation switch matrix so as to maintain a nearly constant output impedance of the PPA throughout the entire modulation range. At maximum PPA output power, all transistors in the load compensation switch matrix are turned off thereby minimizing the extra output loading and reducing the overall power output. As output power decreases, additional numbers of transistors in the load compensation switch matrix are turned on so as to maintain a constant output impedance of the PPA.

Abstract: A method for changing an effective capacitance of an amplifier circuit having a match transistor and a coupled cascode transistor includes changing an on-state of at least one of a plurality of sub-transistors of the match transistor. The method further includes changing a transconductance of the match transistor as a function of the change of the on-state. The method further includes changing an equivalent resistance, as measured between a source and a drain of the cascode transistor, as a function of the change of the transconductance of the match transistor.

Abstract: This document discloses, among other things, a front end circuit having a selectable center frequency. The center frequency is selected based on a control signal proportional to a phase difference between a reference frequency and an amplifier output. A resonant frequency of a tank circuit coupled to the amplifier is tuned using the control signal.

Abstract: A flexible power amplifier can be adapted during operation for use in connection with two or more different wireless standards. In at least one embodiment, adaptations to power transistor size, RF bias current, and matching are made when a corresponding multi-standard wireless device changes the wireless standard under which it is currently operating.

Abstract: An operational amplifier according to an embodiment of the present invention includes: an operational amplifier stage executing differential-amplification of an input voltage and a reference voltage; a source-grounded amplifier stage outputting the differential-amplified signal; a phase compensation capacitance compensating for a phase of an output signal; and a charge/discharge control circuit controlling charge/discharge of the phase compensation capacitance.

Abstract: A method and apparatus are provided for enabling a transmitter to have a substantially linear magnitude response and a substantially linear phase response. The transmitter includes first and second programmable gain amplifiers (PGAs). The first PGA is tuned to have a resonant frequency that is less than an operating frequency of the first PGA. The second PGA is tuned to have a resonant frequency that is greater than an operating frequency of the second PGA. A magnitude response at an output of the first PGA and a magnitude response at an output of the second PGA combine to provide a substantially linear magnitude response across a frequency range that includes the operating frequency of the first or second PGA. According to an embodiment, the first and second PGAs have the same operating frequency.

Abstract: A bias circuit 100 comprises: a first reactance means 2 connected to an AC circuit; a second reactance means 3 connected to the first reactance means 2; a switch 7 connected to a connection point 210 between them; a third reactance means 8 connected to the switch 7; a capacitive means 4 connected to the second reactance means 3; and a DC circuit 5 connected to a connection point 220 between the second reactance means 3 and the capacitive means 4; wherein the connection point 220 is grounded in terms of alternating current. The connection point 210 is at a position such that impedance as viewed from the connection point 210 toward the capacitive means 4 is sufficiently large at a second frequency different from a first frequency. Impedance as viewed from a bias point 800 toward the bias circuit is sufficiently large at any of the frequencies.

Abstract: An adaptively tuned RF power amplifier includes at least one power amplifier stage that has one or more active elements. A tunable output network is coupled to the power amplifier stage and includes one or more adjustable reactive elements. A mismatch detector detects a tuning mismatch based, at least in part, on one or more signals present within the tunable output network, and supplies one or more mismatch signals indicative of a detected tuning mismatch. A tuning controller, responsive to the one or more mismatch signals, controls one or more of the one or more adjustable reactive elements in the tunable output network so as to control the detected mismatch.

Abstract: A high-power amplifier changes matching conditions of an output matching circuit 5 connected between a final stage amplifying element 3 and an output terminal 8 in response to the output power of the amplifying element 3. Thus, the efficiency at low output power can be greatly improved without reducing the efficiency at the maximum output. Besides, since it is not necessary to load a DC-DC converter, an increase in size or cost can be prevented.

Abstract: Methods and corresponding systems in a low noise amplifier include selecting a selected sub-band for amplifying, wherein the selected sub-band is one of a plurality of sub-bands, wherein each sub-band is a portion of a frequency band, and wherein each sub-band has a corresponding sub-band center frequency. Next, a gate-source capacitor is adjusted so that a real part of an LNA input impedance corresponds to a real part of a source impedance at the selected sub-band center frequency. A match capacitor is also adjusted so that the LNA input impedance corresponds to the complex conjugate of the source impedance at the selected sub-band center frequency. The gate-source capacitor and the match capacitor can each be adjusted by recalling capacitor values from memory that correspond to the selected sub-band, and connecting selected capacitor components in response to the recalled capacitor values.

Abstract: Methods and corresponding systems in a low noise amplifier include selecting a selected sub-band for amplifying, wherein the selected sub-band is one of a plurality of sub-bands, wherein each sub-band is a portion of a frequency band, and wherein each sub-band has a corresponding sub-band center frequency. Next, a gate-source capacitor is adjusted so that a real part of an LNA input impedance corresponds to a real part of a source impedance at the selected sub-band center frequency. A match capacitor is also adjusted so that the LNA input impedance corresponds to the complex conjugate of the source impedance at the selected sub-band center frequency. The gate-source capacitor and the match capacitor can each be adjusted by recalling capacitor values from memory that correspond to the selected sub-band, and connecting selected capacitor components in response to the recalled capacitor values.

Abstract: In a broadband low-noise amplifier circuit to be used in a multichannel reception system, a capacitance of a variable capacitor (9) is controlled by a resonance frequency control circuit (4) so that a resonance frequency of a load unit (2) comprising the variable capacitor (9) and an inductor (10) matches a desired RF signal frequency. Therefore, high gain and broadband can be realized at the same time without increasing power consumption, and consequently, a reception system having reduced power consumption and high sensitivity for all channels can be realized.

Abstract: A flexible power amplifier can be adapted during operation for use in connection with two or more different wireless standards. In at least one embodiment, adaptations to power transistor size, RF bias current, and matching are made when a corresponding multi-standard wireless device changes the wireless standard under which it is currently operating.

Abstract: Circuits and methods are provided for building integrated transformer-coupled amplifiers with on-chip transformers that are designed to resonate or otherwise tune parasitic capacitances to achieve frequency tuning of amplifiers at millimeter wave operating frequencies.

Abstract: Circuits and methods are provided for building integrated transformer-coupled amplifiers with on-chip transformers that are designed to resonate or otherwise tune parasitic capacitances to achieve frequency tuning of amplifiers at millimeter wave operating frequencies.

Abstract: A broadband low noise amplifier and amplification method is provided. The broadband low noise amplifier includes an input terminal into which a radio frequency (RF) signal received by an antenna is input, an output terminal from which an amplified RF signal is output, at least one gain control part connected in parallel with loads of the output terminal to adjust the gain of the amplified RF signal, and at least one load tuning part that resonates with loads of the output terminal to adjust the resonance frequency of the load impedance. The method includes amplifying the input RF signal and outputting the amplified RF signal to an output terminal, where a gain of the amplified RF signal is adjusted by switching operations of at least one switching device connected in parallel with a load of the output terminal.

Abstract: A gain boost circuit and methodology are described for providing improved gain boosting with tuned amplifier circuits, such as differential low noise amplifier circuits having output resonant tank circuits. By selectively controlling the current source for a negative transconductance stage coupled between the differential amplifier output and the output resonant tank circuits, the amplifier gain may be adjusted to compensate for temperature variations. In addition, the amplifier gain boost may be selectively added, removed or even incrementally adjusted by using a current source control circuit in the negative transconductance stage to adjust the negative transconductance value generated by the negative transconductance stage.

Abstract: Tunable low noise amplifier using an RF current feed back loop (L) coupled between input (IM) and output (OM) means and including first (CAI) and second (CA2) serially coupled first order lowpass RF current amplifiers as well RF current inverter means (INV). To obtain narrow bandpass selectivity within a relatively wide tuning range e.g. from 40 MHz to 1000 MHz said first RF current amplifier is being provided with a current gain larger than that of the second RF current amplifier, and a 3 dB cut off frequency lower than the 3 dB cut off frequency of said second RF current amplifier, a tuning control signal being supplied to both first and second RF current amplifiers to vary the respective 3 dB cut off frequencies thereof.

Abstract: An amplifier is disclosed for providing processing of a variable RF signal, the amplifier comprising a first parallel gain stage and a plurality of second parallel gain stages electrically disposed between an input fixed impedance matching circuit and an output fixed impedance matching circuit. Wherein in operation each of the first parallel gain stage and plurality of second parallel gain stages are for processing the variable RF signal according to at least a characteristic of the RF power or frequency range. Each of the plurality of second parallel gain stages comprising a tunable impedance matching circuit such that when the second parallel gain stage is in operation the tunable impedance matching circuit providing a transformation of impedance to match between the second amplifier and output fixed matching circuit within the frequency range, and other than providing a match within the frequency range when not in operation.

Abstract: A high-frequency amplifier includes first and second amplifying stages disposed in parallel for amplifying VHF/UHF television signals. The first amplifying stage includes a first FET and a second FET of a grounded-gate type connected in series between a common input terminal and a first output terminal to which a VHF-signal selection circuit is connected, and the second amplifying stage includes a third FET and a fourth FET of a grounded-gate type connected in series between the common input terminal and a second output terminal to which a UHF-signal selection circuit is connected. Switching between amplifying operations of the first and second amplifying stages is performed by an operation switching unit selectively setting one of the first and third FETs in a forward-bias state and the other in a reverse-bias state in response to a switching voltage externally set.

Abstract: A transconductor tuning device tuning a transconductance using a current. The transconductor tuning device includes a tuning section that applies a tuning current and a reference voltage to a transconductor converting an input voltage signal into a current signal and thereby tunes a level of transconductance. The tuning section includes a tuning current generator that converts a bias signal supplied from a bias current source into a certain level of tuning current and outputs the tuning current to the transconductor. The transconductor includes a control voltage generator that generates a certain level of control voltage using the tuning current. Accordingly, the transconductance of the plurality of transconductors are tuned at the same level.

Abstract: An apparatus for amplifying differential signals is provided. The apparatus comprises a differential amplifier, a first impedance component, a second impedance component, a voltage source and a high-pass filter. The differential amplifier receives an input differential signal with a first terminal and a second terminal. The differential amplifier also drains currents from the voltage source into a third terminal and a fourth terminal via the first and the second impedance components respectively. The high-pass filter receives the input differential signal and outputs a control differential signal to control the first and the second impedance components so that the impedance of the first and the second impedance components vary inversely in response to the voltages at the first and the second terminals respectively when the state of the input differential signal changes.

Abstract: According to an example embodiment, an amplitude feedback loop may include an RF amplifier, a detector, a comparator, and a Q-enhancement cell. In an example embodiment, the RF amplifier has an output signal, and the detector has an input coupled to the output signal of the RF amplifier and is configured to detect a level of the output signal of the RF amplifier. The comparator circuit may receive as inputs a reference voltage and the output of the detector. Also, the comparator circuit is configured to output a control signal based on a difference between the reference voltage and the output signal of the power detector. The Q-enhancement cell may be coupled to the RF amplifier and have an input coupled to an output of the comparator circuit. A bias current of the Q-enhancement cell may be adjusted based on the control signal output by the comparator circuit.

Abstract: Provided are a method and system for controlling impedance in a transconductance amplifier. A system includes a first transconductance amplifier and a second transconductance amplifier configured to control electrical characteristics associated with the first transconductance amplifier. An operational amplifier is provided and has at least one input port connected to the second transconductance amplifier. Also included is a first digital to analog converter (DAC) connected to receive a current signal from the operational amplifier.

Abstract: A power amplifying device includes a stabilizing circuit between an input terminal and an amplifier. The stabilizing circuit has a first line, a second line, and a third line. The first line is connected to the ground. The length of the first line is equal to or longer than three fourths of the wavelength of the operating frequency.

Abstract: An adaptive tuning circuit to maximize the output signal amplitude of a band-pass amplifier, comprising a control circuit to tune the peak frequency of the amplifier by monitoring the change in the output signal amplitude over two successive time sampling intervals. In some embodiments, the control circuit comprises an envelope detector and a switched capacitor circuit to provide voltages indicative of the difference in the output signal amplitude over two successive time intervals. Other embodiments are described and claimed.

Abstract: A receiving amplifier includes a semiconductor body with a first node, a second node and an amplifier circuit. The amplifier includes at least one field-effect transistor, a first input, and a second input. A capacitive element is arranged between the inputs of the amplifier circuit, and a tuned circuit whose resonant frequency can be tuned is connected upstream of the amplifier circuit and contains a variable-capacitance element that is connected in parallel with the element in the amplifier circuit. Two inductive elements are also provided, wherein the first inductive element is connected to the first node and the second inductive element is connected to the second node. This results in a series tuned circuit, which leads to a voltage increase at the resonant frequency, and results in an improved signal-to-noise ratio for a signal which is supplied to the receiving amplifier.

Abstract: An adaptive tuning circuit to maximize the output signal amplitude of a band-pass amplifier, comprising a control circuit to tune the peak frequency of the amplifier by monitoring the change in the output signal amplitude over two successive time sampling intervals. In some embodiments, the control circuit comprises an envelope detector and a switched capacitor circuit to provide voltages indicative of the difference in the output signal amplitude over two successive time intervals. Other embodiments are described and claimed.

Abstract: Circuitry and methods for improved amplifiers with large bandwidth and constant gain are provided. The combination of a synthetic inductive drain load and a bridged-T matching network provide amplifiers that can drive a substantial capacitive load with the above mentioned improvements over prior amplifiers. Additionally, circuits presented allow for improved rise time and insensitivity to temperature variations.