121 results about "Broadband amplifiers" patented technology

Provided is a multi-mode multi-frequency power amplifier (100), comprising: a controller (120) for receiving and outputting control signals based on external signals; a broadband amplifier channel (110) for receiving single-frequency or multi-frequency radio-frequency (RF) signals via an input end, conducting power amplification on the RF signals, and outputting the signals via an output end; a fundamental wave impedance convertor (170) comprising a first segment (130) shared by RF signals in respective frequency bands, a second segment (150) dedicated for RF signals in each frequency band, and a switch circuit (140), the switch circuit (140) being controlled by the controller (120) to switchably separate the RF signals with amplified power to the second segment (150) for multiple outputs.

An efficient broadband amplifier. The amplifier includes a mechanism for amplifying an input signal via a high-speed switch and providing an amplified signal in response thereto. Another mechanism filters the amplified signal via common mode rejection and provides an output signal in response thereto. In a specific embodiment, the mechanism for filtering includes a first mechanism for separating an input signal into plural intermediate signals. The mechanism for amplifying includes a second mechanism for amplifying the plural intermediate signals via one or more high-speed switches and providing plural amplified signals in response thereto. The mechanism for filtering further includes a third mechanism for employing common mode rejection to filter the plural amplified signals, yielding a single output signal in response thereto.

The invention relates to a mobile device for detecting local discharging of electric equipment of a substation, and a positioning method. The detecting device is mounted on mobile equipment and is composed of an antenna matrix, an ultra high-speed data sampling unit and a data processing unit. The positioning method comprises the following steps: using an ultra-high frequency (UHF) antenna to receive an ultra-high frequency electromagnetic wave generated by to-be-detected local discharging of the electric equipment of the substation; after performing amplifying and filtering treatment on the ultra-high frequency electromagnetic wave by a prepositioned broadband amplifier, synchronously sampling by virtue of the ultra high-speed data sampling unit, sending to the data processing unit and performing data processing on a four-way signal; and displaying the position of a local discharging source and early warning information on a display screen. The detecting device and positioning method provided by the invention can be used for thoroughly detecting and positioning the local discharging of all equipment in the substation; the detecting cost of the local discharging of the equipment in the substation is greatly lowered; the defects can be early found while the substation is subjected to routing inspection; power-off accidents are reduced, thereby increasing the intelligent level of the substation; and the detecting device and the positioning method have the characteristics of low cost and high efficiency and can quickly detect and position the local discharging of the whole to-be-detected substation.

An efficient broadband amplifier. The amplifier includes a mechanism for amplifying an input signal via a high-speed switch and providing an amplified signal in response thereto. Another mechanism filters the amplified signal via common mode rejection and provides an output signal in response thereto. In a specific embodiment, the mechanism for filtering includes a first mechanism for separating an input signal into plural intermediate signals. The mechanism for amplifying includes a second mechanism for amplifying the plural intermediate signals via one or more high-speed switches and providing plural amplified signals in response thereto. The mechanism for filtering further includes a third mechanism for employing common mode rejection to filter the plural amplified signals, yielding a single output signal in response thereto.

The invention discloses a fourth-generation multi-standard fully-compatible mobile radio-frequency front-end broadband low-noise amplifying device which comprises a single-end input and differential output noise cancellation type low-noise amplifier, a tracking filter quality factor boosting circuit and a class AB module, wherein the single-end input and differential output noise cancellation type low-noise amplifier is used for enabling noise cancellation and signal complementary addition by the aid of opposite phases of signals and noise; the tracking filter quality factor boosting circuit is used for increasing quality factors of an output cavity by adjusting negative transconductance so as to obtain optimal out-of-band interference filtering effects; and the class AB module is used for enabling a current mode amplifier not to be unsaturated so as to respond to strong out-of-band interference. The broadband amplifier adopts single-end input and uses single inductor to meet noise performance, can filter large out-of-band signals and covers TD-LTE (time division-long term evolution), TD-SCDMA (time division-synchronous code division multiple access) and quad-band GSM (global system for mobile communications), and the fourth-generation multi-standard fully-compatible mobile radio-frequency front-end broadband low-noise amplifying device has the advantages of low cost, multiple applicable standards, high data rate, high sensitivity, low noise and small occupied space.

An apparatus and method to improve broadband amplifier linearization. The present circuits make use of pre-distortion techniques to improve the 3rd order distortion of an amplifier to reduce the amount of DC power required to achieve a given system requirement. In addition, the amplifiers have broadband characteristics which lend themselves to simplified pre-distortion. A pre-distortion linearizer circuit is connected across the input terminals of an amplifier. The linearizer circuit includes multiple diodes to improve the clipping performance of the linearizer. In addition, RC circuits align the phase of the linearizer distortion to be opposite that of the amplifier.

A method and apparatus for providing a linearized wideband RF amplifier includes processing the RF output signal from the amplifier to obtain a carrier-free processed signal of 180° phase inverted distortion products in the RF output signal, whereby the processed signal is amplified and summed with the distorted output signal from an associated power amplifier for removing the distortion products from the RF output signal.

Provided herein are multi-stage broadband amplifier configured to achieve a high gain-bandwidth product in a non-distributed architecture and methods for designing the same. The broadband amplifier can include an input stage having a broadband matching unit and an input buffer unit, a gain stage having an RLC network and a amplifier unit and an output stage having a common collector amplifier and an RC compensation unit.

The invention relates to a four-channel nuclear magnetic resonance signal full-wave acquisition system and acquisition method. The system is constructed in such a way that a computer is connected with a first controller; the first controller is connected with a power management module through a high-speed digital I / O card and a second controller; the first controller is respectively connected with broadband amplifiers through an acquisition card; and the computer is connected with a GPS module through the second controller. A preamplifier effectively resists amplifier saturation, by use of Q_SWITCH, the dead zone time is shortened, the signal-to-noise ratio is improved, the synchronization precision is improved, false triggering is prevented, noise signals are remotely transmitted by use of currents, the signal attenuation during a transmission process is effectively inhibited, data processing is performed on acquired nuclear magnetic resonance signals by use of a self-adaptive reference de-noising algorithm, the anti-interference capability of an instrument is enhanced, the dynamic scope of the instrument is improved, it is possible that a nuclear magnetic resonance method can be applied to a large-noise area, and the transverse resolution and accuracy of measuring underground water body distribution are effectively improved. Multi-channel measuring improves the working efficiency, and the positioning of an underground water body is accurate.

The invention discloses a piezoresistive high-frequency high-temperature dynamic pressure sensor, which consists of a piezoresistance sensitive component, a sensor metal shell, and a high-frequency broadband amplifier, wherein the piezoresistance sensitive component consists of a silicon piezoresistance sensitive component and a glass ring piece; the silicon piezoresistance sensitive component is formed by a circular-flat silicon diaphragm which is sequentially covered by a SiO2 layer and a Si3N4 layer on the front; the middle part of the front of the silicon piezoresistance sensitive component is provided with a Wheatstone bridge, while the silicon diaphragm is exposed at the periphery of the silicon piezoresistance sensitive component and is firmly welded to the glass ring piece; the back of the silicon piezoresistance sensitive component is provided with a metal reflective film, and a strain resistor on the Wheatstone bridge is led out by a gold wire internal down-lead; the other side of the glass ring piece is fixed to an annular concave pit surface on a ceramic isolation substrate; the ceramic isolation substrate is sintered and fixed at a pressure inlet port of the sensor metal shell; and after the gold wire internal down-lead on the piezoresistance sensitive component is led to an adapter plate in an inner chamber of the sensor, signals are amplified by the high-frequency broadband amplifier and are led out through an output cable at the tail of the sensor. The piezoresistive high-frequency high-temperature dynamic pressure sensor still has good characteristics when bearing superhigh temperature and superhigh frequency impact.

The invention discloses a phase noise calibrating device based on a photoelectric fusion technique, which comprises a microwave amplifier (2), a power divider (3), a phase shifter (4), a modulator (5), an attenuator (6) and a phase noise measurement system (10), and further comprises a photoelectric oscillator (1), a microwave noise source (9), a broadband amplifier (8) and a band-pass filter (7). The photoelectric oscillator is developed through the photoelectric fusion technique, so the phase noise calibrating device has a large phase noise standard dynamic range and a simple structure, and can calibrate the phase noise measurement result precision, so the defects of the existing calibrating method are overcome, and thus, the phase noise measurement result precision traceability of a microwave frequency band is obtained.

A low-noise broadband optical fiber trans-impedance amplifier belongs to the field of optical fiber communication receiver systems technology and comprises an input stage, a pseudo-input stage, a broadband amplifier unit, a broadband output stage and a DC elimination loop. The pseudo-input stage has the same structure with the input stage. The broadband amplifier unit is mainly composed of two diodes and a Cherry-Hooper amplifier. The broadband output stage is mainly composed of six NPN tubes and two resistors. The DC elimination loop is mainly composed of two low pass filters LPF, an error amplifier ERR_AMP and an NPN tube. The low-noise broadband optical fiber trans-impedance amplifier has advantages as follows: noise of an optical fiber trans-impedance amplifier can be reduced; bandwidth of the optical fiber trans-impedance amplifier can be raised; and DC component of front-end photodiodes can be eliminated.

A high frequency broadband amplifier used for piezoresistive dynamic pressure sensor, connected between outlet line of dynamic pressure sensor, including two-stage amplifiers, power filter circuit and signal filter circuit, the first-class amplifier was composed of the instrument amplifier, its input and negative feedback ends connect the two differential output end of the sensor; the second-class amplifier was composed of high-speed operational amplifier, its input end connect the output end of the instrument amplifier; the power filter circuit were positive or negative, individually parallel connect two electrolytic capacitors or two ceramic capacitors with the earth; the signal filter circuit was self-made band-pass filter consisted by three Y connected inductions, one induction concatenate the high-frequency ceramic capacitor, then connect with the outlet end of the operational amplifier, the other one parallel connect the high-frequency ceramic capacitor, then connect the earth; the last one was took as the outlet end of the amplifier after first connected in series the high-frequency ceramic capacitor. This invention is of high frequency, low noise, with fast rise speed, and anti-interference.

An amplifier having programmable amplification includes a transistor circuit having a plurality of negative feedback resistors, a switch being associated to a negative feedback resistor such that the negative feedback resistors of the transistor circuit can be activated and deactivated selectively by operating switches via a controller. Thus, a broadband amplifier having a high linearity can be implemented.

Provided herein are multi-stage broadband amplifier configured to achieve a high gain-bandwidth product in a non-distributed architecture and methods for designing the same. The broadband amplifier can include an input stage having a broadband matching unit and an input buffer unit, a gain stage having an RLC network and a amplifier unit and an output stage having a common collector amplifier and an RC compensation unit.

An apparatus and method to improve broadband amplifier linearization. The present circuits make use of pre-distortion techniques to improve the 3rd order distortion of an amplifier to reduce the amount of DC power required to achieve a given system requirement. In addition, the amplifiers have broadband characteristics which lend themselves to simplified pre-distortion. A pre-distortion linearizer circuit is connected across the input terminals of an amplifier. The linearizer circuit includes multiple diodes to improve the clipping performance of the linearizer. In addition, RC circuits align the phase of the linearizer distortion to be opposite that of the amplifier.

The invention relates to a device and a method for online monitoring of partial discharge of a shunt capacitor. The device comprises a capacitor, a broadband partial discharge sensor, a high-frequency coaxial cable, a signal hardware adjusting unit, an A / D (analog / digital) acquisition card and an industrial personal computer. The broadband partial discharge sensor is installed at the lower end connecting wire of the capacitor in a sleeving way and connected with the signal hardware adjusting unit through the high-frequency coaxial cable; the signal hardware adjusting unit is connected with a data acquisition device through the high-frequency coaxial cable; and the data acquisition device is connected with the industrial personal computer through a USB (universal serial bus) connecting wire. According to the device for online monitoring of partial discharge of the shunt capacitor, a partial discharge signal is sensed by a wide-band rogowski coil partial discharge sensor, the original connection way of equipment is not changed and high detection sensitivity is obtained. A band-pass filter with adjustable frequency band width and a broadband amplifier are adopted by the device, so that the detection sensitivity is improved greatly, the partial discharge signal can be effectively monitored, the partial discharge state of the capacitor in operation can be known in real time, and an equipment insulation fault is avoided.

The invention belongs to the design field of radio frequency integrated circuits, which in particular discloses a low-noise broadband amplifier with linearity compensation. The circuit comprises an active feedback unit, a current multiplexing transconductance unit, a direct-current feedback unit and a low-power supply voltage offset unit with the linearity compensation, wherein the direct-current feedback unit is used for stabilizing working points; the active feedback unit realizes broadband input impendence matching; the current multiplexing transconductance unit uses one transistor complementary with a main transconductance unit to serve as the other transconductance unit to improve gain under the condition of the same power consumption; a direct-current feedback loop is used for stabilizing the working points of the circuit; and the low-power supply voltage offset unit with the linearity compensation has the function of linearity compensation under the condition of providing offset to the circuit. According to the low-noise broadband amplifier, the low-noise amplifier with high linearity can be obtained by costing lower power consumption by the CMOS (Complementary Metal-Oxide-Semiconductor Transistor) technology.

The invention relates to the technical field of radars, in particular to a time division multi-random code generator for a radar, which consists of a broadband noise generator, n groups of surface acoustic wave SAW bandpass filters, microwave broadband amplifiers, a voltage comparator, a sampling holder, and an active integrator; the PN junction of a noise diode is doped with an annular diffusionregion to inhibit the generation of uncontrollable noise; the code frequency of the broadband noise generator is cascaded and segmented from low to high and outputs P1, P2, and Pn groups of random two-phase codes through n groups of bandpass filter amplifiers, the voltage comparator and the sampling holder; and the random two-phase codes are fed back by the active integrator, and are coded in a time-division circuit to generate n paths of pulses to supply to a radar phase modulator and a multichannel pulse correlator. The random two-phase codes have higher resolution when a target to be detected is closer; linear increasing resolution accumulative detection signals improve details of a target to be identified; and time division multi-random code generators are not interfered with each other when working in the same regional environment, overcome the defect that continuous wave radar emission signals block the receiving of back waves, eliminate blind distance, and realize short-distancedetection. The time division multi-random code generator is suitable for collision-proof radars for automobiles and ships and other multi-target detection radars.

The invention discloses a circuit of a low-noise broadband amplifier, which comprises a first-stage circuit and a second-stage circuit, wherein the first-stage circuit comprises two phase inverters. Both ends of a differential input signal are respectively connected with the input ends of the two phase inverters. The second-stage circuit also comprises two phase inverters. The output ends of the two phase inverters of the first-stage circuit are respectively connected with the input ends of the two phase inverters of the second-stage circuit. The first-stage circuit and the second-stage circuit are isolated by a current source, the second-stage circuit and a power supply are also isolated by a current source, and the output ends of the two phase inverters of the second-stage circuit are the output ends of the circuit of a low-noise broadband amplifier. The invention uses the two-pole structure of current multiplexing and has excellent stability and high gain performance, and the power consumption is also greatly reduced; the second-stage circuit has the effect of resisting the reverse kick of a back loading circuit, and higher gain is realized.

The invention discloses a high-sensitivity front-end circuit of a transimpedance amplifier (TIA). In the front-end circuit, a broadband amplifier is added between a load resistor and a second field-effect transistor in an existing circuit; the broadband amplifier comprises a third field-effect transistor, a fourth field-effect transistor, a second load resistor and a third load resistor; one end of the second load resistor is connected with a drain electrode of the third field-effect transistor and the other end of the second load resistor is connected with a power supply; one end of the third field-effect transistor is connected with a drain electrode of the fourth field-effect transistor and the other end of the third field-effect transistor is connected with the power supply; a grid electrode of the third field-effect transistor is connected with a drain electrode of the first field-effect transistor; a grid electrode of the fourth field-effect transistor is connected with a first input voltage and is earthed by a second capacitor; source electrodes of the third field-effect transistor and the fourth field-effect transistor are earthed respectively by a current source; and a grid electrode of the second field-effect transistor is connected with the drain electrode of the fourth field-effect transistor. The high-sensitivity front-end circuit can improve the bandwidth and sensitivity of the transimpedance amplifier remarkably and strengthen the transmission rate of the photoelectric signals or enlarge the transmission distance of the photoelectric signals.

The invention discloses a broadband amplifier of which the gain reduction is smaller than 0.5 dB within the band frequency ranging from 500 MHz to 1000 MHz. The broadband amplifier comprises a self-biasing circuit, an inner feedback circuit, an outer feedback circuit and a multi-stage current amplifying circuit, wherein the self-biasing circuit is a mirror current circuit of a last-stage current circuit of the multi-stage current amplifying circuit and determines the lower limit of the operating frequency of the broadband amplifier, the inner feedback circuit dynamically changes the bias voltage provided for a first-stage current amplifying circuit of the multi-stage current amplifying circuit according to the feedback voltage of an output end of the broadband amplifier, namely an output end of the multi-stage current amplifying circuit and the feedback voltage of an output end of the self-biasing circuit, and the outer feedback circuit feeds the changes of the output end of the multi-stage current amplifying circuit to an input end of the broadband amplifier, namely an input end of the multi-stage current amplifying circuit. The broadband amplifier is particularly suitable for the emitting and transmitting process of a cable television (CATV).

The invention provides a high-flatness broadband amplifier, comprising a distributed amplifier and a feedback compensation circuit. One end of each feedback compensation branch in the feedback compensation circuit is connected with a control end of a corresponding transistor in the distributed amplifier, and the other end is grounded. The feedback compensation branches access impedances of corresponding values to the control ends of the corresponding transistors, so parasitic parameters of the transistors are variable parameters. The parasitic parameters cause cut-off frequencies of artificial transmission lines to be changed along with the change of input signal frequencies, so the flatness of the distributed amplifier is optimized.

The invention discloses a low-power-consumption low-noise broadband amplifier, which belongs to the technical field of integrated circuits and comprises an input turn-off matching network, a negative feedback dual-stack current multiplexing amplification network, an output turn-off matching network, a switch control circuit and an enable control circuit. According to the negative feedback double-stacked current multiplexing amplification network, an input and output turn-off matching architecture is combined, so that an amplifier has an enabling turn-off function, and low noise, high linearity, high gain and broadband characteristics and good on-state standing wave characteristics in a low power consumption mode can be realized in an on state; and when the amplifier is turned off, the amplifier still keeps good turn-off standing wave characteristics.

The invention provides a portable digital storage oscilloscope based on SOPC technology. A to-be-detected signal is outputted to an RC attenuation circuit via an optocoupler, attenuation switching on the to-be-detected signal is completed, a broadband amplifier carried out buffer isolation on the to-be-detected signal after attenuation, a variable gain amplifier is used for adjusting the gain of the to-be-detected signal, the to-be-detected signal after adjustment is mixed with reference level via an ADC driver, analog-to-digital conversion is carried out via the ADC, an FPGA is used for storing and controlling a sampling signal, amplitude operation and frequency operation on the data are completed, spectrum analysis operation is carried out, and operation results are outputted to a man-machine interaction module for display. A hardware circuit is simplified, power consumption, the size and the cost are reduced, the sampling rate is high, and functions of signal waveform measurement, peak value measurement, effective value measurement, frequency measurement and signal spectrum analysis can be realized.

The invention discloses a broadband low-phase-noise step frequency synthesizer and a frequency synthesizing method. The synthesizer comprises a controller, an analog-to-digital converter, an integrated phase discriminator, an analog switch, a broadband VCO, a coupler, a broadband amplifier, a mixer, a first low-pass filter, a second low-pass filter, a radiofrequency amplifier, a comb spectrum generator and a crystal oscillator. The broadband low-phase-noise step frequency synthesizer and the frequency synthesizing method combine the comb spectrum generator and a PLL, achieves not only a broadband but also ultralow phase noise by using the frequency selection function and the frequency division function of the PLL, realize a fine stepping capability without using DDS, and can simultaneously achieve broadband low-phase-noise fine stepping and a small size and low power consumption.

The invention discloses a high-stability crystal oscillator circuit and an implementation method. The circuit comprises a broadband amplifier, a double-arm bridge network connected with the broadband amplifier, an amplifier connected with the double-arm bridge network, an amplitude limiter and an emitter follower, wherein the amplitude limiter and the emitter follower are connected with the amplifier through a DC blocking capacitor C403. The double-arm bridge network is composed of an RLC network and a crystal resonator. One end of the crystal resonator is connected with the broadband amplifier, and the other end is connected with the RLC network output end; the RLC network is connected in series with an adjustable resistor R402, an inductor L400 and a capacitor C401, and the capacitor C400 is connected in parallel with the two ends of the adjustable resistor R402, the inductor L400 and the capacitor C401 which are connected in series. The invention provides a novel oscillation circuit, which reduces the sensitivity of oscillation frequency to environmental conditions while ensuring other high-stability crystal oscillator technical means, and further improves the frequency stability index of the crystal oscillator.

The present invention relates to the geophysical exploration field, in particular relates to an analog comb filter-based magnetic resonance underground water detection device and an analog comb filter-based magnetic resonance underground water detection method. The analog comb filter-based magnetic resonance underground water detection device comprises a computer, a receiver, a synchronization unit, an emitter, an emission coil connected with the output of the emitter and a reception coil connected with the input of the receiver, wherein the computer sends an instruction to the receiver via a communication interface, the receiver processes an upper computer instruction, and the synchronization unit synchronizes the receiver and the emitter; the receiver controls the reception coil to receive a signal, the signal received by the receiver passes a prepositive amplifying unit, a bandwidth filtering unit, a comb filtering unit and a secondary amplifying unit orderly and then is transmitted by an acquisition card unit to the computer. According to the present invention, by adding a comb filter aiming at a power frequency harmonic in the passband of a broadband amplifier, the power frequency harmonic nearby the signal is suppressed very well, at the same time, the situation that the suppression to an effective signal is minimum is guaranteed.

The invention discloses an infrared radiometer applied in a vacuum low-temperature environment. The infrared radiometer comprises an outer calibration source, an optical system, an inner calibration source, a modulation fan, an infrared detector assembly, a pre-broadband amplifier, a lock-in amplifier and a data acquisition processing and control device. The inner calibration source and the outercalibration source are used for calibrating the infrared radiometer; the optical system is used for collecting target light; the modulation fan is placed between the optical system and the infrared detector assembly, modulates detected optical radiation and serves as synchronous input of the lock-in amplifier; the pre-amplifier amplifies an output signal of the infrared detector assembly and outputs the output signal to the lock-in amplifier, and after the output signal is processed by the lock-in amplifier, a signal in direct proportion to an infrared radiation quantity value of a measured target is formed, is collected by the AD and is processed by a computer and software to form a measurement result. In the invention, on-orbit multi-point, high-precision, wide-temperature-range and rapid magnitude traceability or radiation magnitude measurement of the calibration source for on-orbit calibration can be realized.