60results about How to "Linear characteristic" patented technology

An embodiment of the invention uses a predistortion correction signal to combination the modulated RF signal by an analog multiplier for linearization of power amplifiers having nonlinear characteristics such as those used in wireless RF transmitters. A predistortion controller comprises a plurality of down converters for retrieving both the ideal non-distorted information and the feedback distorted information, together with pre-stored digitally-indexed predistortion information stored, for example, in a look-up table. The digitally-indexed information models nonlinear characteristics of the high power amplifier, and is stored prior to processing of pre-compensation in the power amplifier. When the predistortion information is combined with the modulated RF signal in the analog multiplier, the result is a substantially linear information transmission from the power amplifier. In an embodiment of the system, the modulated RF input signal and the feedback signal from PA output are down-converted, respectively, by analog devices, such as mixers, after which the analog intermediate frequency (IF) signals are digitized by analog-to-digital converters for digital predistortion correction processing, followed by predistortion processing performed by, for example, a DSP or FPGA chip to generate a digital correction control signal, which is then converted to an analog signal by a digital-to-analog converter, followed by combining the analog correction signal with the RF modulated input signal to yield the input to the power amplifier.

A gain control amplification circuit of this invention has a gain control amplification section which has at least two stages and is arranged in the transmission circuit of a terminal equipment for communicating with a base station. The gain control amplification section includes gain control amplifiers of IF-GCA and RF-GCA arranged on the input side (former stage) and output side (latter stage) of an up converter in the transmission circuit. The gains of the gain control amplifiers are individually controlled by a control section.

A linear amplification with nonlinear components (LINC) power transmitter is provided. The LINC power transmitter includes a digital signal processing unit which controls the LINC power transmitter; a frequency modulation unit which modulates or converts a digital signal output from the digital signal processing unit into a radio-frequency (RF) signal; a signal amplification unit which amplifies the RF signal output from the frequency modulation unit using a gain amplifier and a power amplification module; and a direct current / direct current (DC / DC) conversion unit which controls bias of the power amplification module. Here, the DC / DC conversion unit controls a base bias and / or a collect bias of the power amplification module, and the power amplification module operates in saturation.

Impedance-matched output driver circuits include a first totem pole driver stage and a second totem pole driver stage. The first totem pole driver stage includes at least one PMOS pull-up transistor and at least one NMOS pull-down transistor therein that are responsive to a first pull-up signal and a first pull-down signal, respectively. The second totem pole driver stage has at least one NMOS pull-up transistor and at least one PMOS pull-down transistor therein that are responsive to a second pull-up signal and second pull-down signal, respectively. The linearity of the output driver circuit is enhanced by including a first resistive element that extends between the first and second totem pole driver stages. The first resistive element has a first terminal, which is electrically coupled to drain terminals of the at least one PMOS pull-up transistor and the at least one NMOS pull-down transistor in the first totem pole driver stage, and a second terminal, which is electrically coupled to source terminals of the at least one NMOS pull-up transistor and the at least one PMOS pull-down transistor in the second totem pole driver stage.

An improved optical receiver comprises a vertically lasing semiconductor optical amplifier (VLSOA) coupled to a photodetector. The VLSOA and photodetector are discrete devices or alternatively integrated onto a common substrate. The integrated optical receiver may be fabricated using a number of different methods, including based on selective area epitaxy, impurity induced disordering, etch and fill and silicon optical bench.

A wireless communication system has a first operation mode (GSM mode) for amplifying a phase-modulated high frequency signal with a high frequency power amplifier circuit and a second operation mode (EDGE mode) for amplifying a phase and amplitude-modulated high frequency signal with the amplifier circuit. The amplifier circuit has an input of a high frequency signal, with the amplitude and frequency being fixed in both the first and second operation modes, and operates by being controlled for the bias state of each amplifying stage in accordance with the output control signal produced by a control circuit based on the demanded output level (Vapc) and the detected output level (VSNS) so that the amplifier circuit performs signal amplification to meet the demanded output level.

A wireless communication system has a first operation mode (GSM mode) for amplifying a phase-modulated high frequency signal with a high frequency power amplifier circuit and a second operation mode (EDGE mode) for amplifying a phase and amplitude-modulated high frequency signal with the amplifier circuit. The amplifier circuit has an input of a high frequency signal, with the amplitude and frequency being fixed in both the first and second operation modes, and operates by being controlled for the bias state of each amplifying stage in accordance with the output control signal produced by a control circuit based on the demanded output level (Vapc) and the detected output level (VSNS) so that the amplifier circuit performs signal amplification to meet the demanded output level.

In the mobile communication, a distortion compensation amplifying apparatus is provided. In a predistortion-type distortion compensation amplifying apparatus (9), a signal amplitude change processing unit (10) comprises an odd-power component calculating unit (14) extracting a power component of odd order of an amplitude quantity contained in a signal to be transmitted and outputting it, a coefficient information outputting unit (15) being operable to select one of plural pieces of coefficient information based on a signal from the outside and output it, a multiplying unit (16) multiplying a signal outputted from the odd-power component calculating unit (14) by coefficient information from the coefficient information outputting unit (15) and outputting an attenuation signal, and an adding unit (17) subtracting the attenuation signal from the signal to be transmitted and outputting a result, thereby making an amplifier operate within a range not exceeding a saturation region thereof, decreasing a spurious signal, decreasing an adjacent channel power, and enabling distortion compensating operation even if a frequency of reference to the memory is decreased.

An improved optical transmitter comprises a vertically lasing semiconductor optical amplifier (VLSOA) coupled to an external modulator and / or a laser source. The VLSOA, external modulator and laser source are discrete devices or alternatively integrated onto a common substrate. The integrated optical transmitter may be fabricated using a number of different methods, including based on selective area epitaxy, impurity induced disordering, etch and fill and silicon optical bench.

Ferroelectric memory cells (3) are presented, in which a cell resistor (R) is integrated into the cell capacitor (C) to inhibit charge accumulation or charge loss at the cell storage node (SN) when the cell (3) is not being accessed while avoiding significant disruption of memory cell access operations. Methods (100, 200) are provided for fabricating ferroelectric memory cells (3) and ferroelectric capacitors (C), in which a parallel resistance (R) is integrated in the capacitor ferroelectric material (20) or in an encapsulation layer (46) formed over the patterned capacitor structure (C).

The invention concerns a reverse osmosis system (1) with a membrane unit (2) comprising an inlet (3), a permeate outlet (4) and a concentrate outlet (5), a high-pressure pump (8) that is connected to the inlet (3), a pressure exchanger (11) connected on its concentrate side (10) to the concentrate outlet (5), and a booster pump between the pressure exchanger (11) and the inlet (3). It is endeavoured to make the energy consumption as small as possible. For this purpose, the booster pump is made as a displacement pump.

The invention is directed to a tunable, capacitive component that includes a pair of MOS transistors whose gate connections are connected via a respective coupling capacitance to a pair of circuit nodes between which the tuned capacitance can be tapped off. The four load connections of the MOS transistors are connected to one another. In addition, a tuning input and a reference signal input are provided that are both coupled to the transistor pair. In this arrangement, the reference signal input is designed for setting the operating point of the transistors. The tunable capacitance has a large tuning range and also a low series resistance and permits good linearity properties on account of the operating point setting. The component can be used advantageously in LC oscillators.

The present invention relates to a circuit configuration (10) having a feedback operational amplifier (AMP) for amplifying an input signal (Vin) input into the circuit arrangement (10) and outputting the amplified input signal as an output signal (Vout). In order to be able to change the circuit amplification (Vout / Vin) easily and reliably in the circuit configuration (10) and simultaneously keep an impairment of the output signal (Vout) caused by noise relatively low, capacitance values (Cb, C) of the coupling path (12) and of the feedback path (14) are adjusted simultaneously to one another correlated in a special way.

An interior magnet linear induction motor includes an armature and a line of inductor teeth. The armature includes coils arranged between a plurality of teeth, and the line of inductor teeth is arranged so as to face the armature and includes a plurality of tooth portions arranged at a constant pitch in a linear stroke direction. An end portion of each of the plurality of teeth has a shape such that magnetoresistance of the tooth increases toward the root side. At least one permanent magnet is arranged at an end portion of each of the plurality of teeth and adjacent permanent magnets that are arranged at different teeth are magnetized such that opposite magnetic poles face each other.

A linear amplification with nonlinear components (LINC) power transmitter is provided. The LINC power transmitter includes a digital signal processing unit which controls the LINC power transmitter; a frequency modulation unit which modulates or converts a digital signal output from the digital signal processing unit into a radio-frequency (RF) signal; a signal amplification unit which amplifies the RF signal output from the frequency modulation unit using a gain amplifier and a power amplification module; and a direct current / direct current (DC / DC) conversion unit which controls bias of the power amplification module. Here, the DC / DC conversion unit controls a base bias and / or a collect bias of the power amplification module, and the power amplification module operates in saturation.

A system and method are disclosed for effectively compensating for an unbalanced or non-zero centerline radio-frequency potential in a quadrupolar ion trap, the unbalanced centerline potential created by a compensation feature that minimizes non-linear field components created by one or more ejection slots in the ion trap. The ion trap includes a centerline that passes longitudinally through a trapping volume inside of the ion trap, a pair of Y electrodes with inner Y electrode surfaces that are approximately parallel to the centerline, and a pair of X electrodes with inner X electrode surfaces that are approximately parallel to the centerline. The X electrodes have ejection slots through which trapped ions are ejected from the ion trap. A Y signal with a Y signal amplitude is coupled to both of the Y electrodes. An X signal with an X signal amplitude is coupled to both of the X electrodes. The X signal amplitude is selected to be greater than the Y signal amplitude to thereby create a balanced centerline potential at the centerline of the ion trap device.

A circuit with variable capacitance includes a capacitance, wherein the capacitance includes a first partial capacitance and a second partial capacitance connected in parallel to the first partial capacitance, wherein a capacitance value of the first partial capacitance depends on a first bias of the partial capacitance, and a capacitance value of the second partial capacitance depends on a second bias of the second partial capacitance. The circuit with variable capacitance further includes a unit for providing the first bias and the second bias. With such a circuit with variable capacitance, it is possible to achieve a more linear and flatter characteristic tuning curve of the circuit with variable capacitance as compared to a conventional circuit with variable capacitance in a simple way.

A GaAs based semiconductor laser having a combination of cladding layers including a ridge structure part, and a remaining part which overlays the active layers of the laser, and an etch stop layer sandwiched between the ridge structure part and the remaining part. The remaining part preferably overlies the entire surface of laser active layers and has a thickness “D” which satisfies 1.1×W>D≧0.5×W wherein W is the width of a spot size having a strength of 1 / e2 as measured at the laser front facet in a direction perpendicular to the active layers, wherein “e” is the base of the natural logarithm. The semiconductor laser solves the kink phenomenon to obtain an excellent linear relationship between the optical output power and the injected current.

An amplifier arrangement and also a control loop having the amplifier arrangement are specified, wherein the amplifier arrangement is based on a Gilbert multiplier. Connected in parallel in this case with one of the transistors of the differential amplifier cells is an additional transistor, at which it is possible to tap off a signal that is proportional to the gain factor. Processing this signal in a suitable manner, for example in a control loop, makes it possible to compensate for temperature and manufacturing fluctuations and also to obtain a highly linear characteristic curve having a gain factor which can be set in a stable manner. In addition, the structure shown is current-saving and can be used, in particular, for application in radio frequency technology as an amplifier having a variable gain factor (VGA).

A wide dynamic range trans-impedance amplifier includes a first trans-impedance amplifier configured to receive a first input current and produce a first voltage as a function of the first input current, and a second trans-impedance amplifier configured to receive a second input current and produce a second voltage as a function of the second input current. A current steering element causes a first portion of current from a current source to flow to the first trans-impedance amplifier until the first current portion reaches the first threshold current, and causes a second portion of current from the current source to flow to the second trans-impedance amplifier, until the second current portion reaches the second threshold current. The second current portion is current from the current source that exceeds the first threshold current. The wide dynamic range trans-impedance amplifier may receive, for example, ion collector current from a hot cathode ionization gauge (HCIG).

The present invention provides a communication semiconductor integrated circuit device equipped with a high-frequency power amplifier circuit including a gain control amplifier and a bias circuit which supplies such a bias current as to linearly change the gain of the gain control amplifier, and a wireless communication system using the same. A bias current generating circuit which supplies a bias current to a linear amplifier that constitutes the communication high-frequency power amplifier circuit, comprises a plurality of variable current sources respectively different in current value and start level. These variable current sources are controlled according to an input control voltage and thereby combine their currents into a bias current. The combined bias current changes exponentially with respect to the input control voltage.

A CDMA system is provided which includes a power amplifier module have a DC current amplifier. The DC and current amplifier detects a DC component of an input signal and amplifies this detected DC component. The power amplifier module also includes an amplifier which receives the current amplified by the DC current amplifier as an input current. The input signal supplied to the DC current amplifier changes in response to an input power level.

A voltage controlled oscillator of the present invention comprises a reference voltage generation section 114 for generating a plurality of reference voltage based on a power supply voltage. A first to a third reference voltages Vref1, Vref2, and Vref3 are inputted to a first to a third variable capacitance circuits A, B, and C, respectively, at each one of terminals of each of the first to the third variable capacitance circuits A, B, and C. The first to the third reference voltages Vref1, Vref2, and Vref3 each has a fixed value, and a difference between the first reference voltage Vref1 and the second reference voltage Vref2 and a difference between the second reference voltage Vref2 and the third reference voltage Vref3 represent values different from each other. A control voltage Vt for feedback-controlling an oscillation frequency is inputted to each of the other of the terminals of the variable capacitance element of each of the n variable capacitance circuits such that the control voltage Vt having the same value is inputted to said each of the other of the terminals.

The electromagnetic vibration exciter system with an adjustable electro-viscoelastic suspension device comprises an electromagnetic vibration exciter, a power amplifier and an adjustable electro-viscoelastic suspension device, which acts as the suspension device of the electromagnetic vibration exciter. The adjustable electro-viscoelastic suspension device contains a displacement sensor detecting the displacement of the moving component, a first adjustable amplifier and a second adjustable amplifier, a differentiator, an adjustable phase shifter, an adder and a proportioner. The linearity of the stiffness and damping of the exciter system is excellent, which can be adjusted as need through the adjustment of gain of the adjustable amplifier, the proportioner, the adjustable phase shifter. This invention has adjustable and linear parameters and it is also easy to be realized.

A micromechanical sensor comprising a substrate (5) and at least one mass (6) which is situated on the substrate (5) and which moves relative to the substrate (5) is used to detect motions of the sensor based on an acceleration force and / or Coriolis force which occur(s). The mass (6) and the substrate (5) and / or two masses which move toward one another are connected by at least one bending spring device (1) for a relative rotational motion. The bending spring device (1) has multiple, in particular two, spring bars (2) extending essentially parallel to one another for improving the linear spring characteristic of the bending spring device during the rotational motion, and at least one meander (3) on at least one, preferably on all, of the spring bars (2).

A receiver system comprises an antenna configured to receive an input RF signal, a high spur free dynamic range modulator configured to receive the input RF signal from the antenna and to convert the input RF signal to an optical signal, and a tunable filter configured to receive the optical signal and to output a filtered optical signal. The tunable filter includes at least one electro-optic resonator, at least one electrode configured to supply an electrical control signal to the electro-optic resonator, and a controller configured to adjust the electrical control signal to adjust a refractive index of the electro-optic resonator, whereby a resonant frequency of the electro-optic resonator is selectably adjusted. The receiver system further comprises a receiver configured to receive the filtered optical signal.