274 results about "Variable-gain amplifier" patented technology

The invention belongs to the technical field of signal acquisition and processing, and discloses a low-noise biopotential signal acquisition system and a low-noise biopotential signal processing method. An original bioelectricity signal of a human body is collected through an electrode array, and analog-to-digital conversion is carried out after the signal is processed by a multi-stage self-adaptive filtering and amplifying circuit. A digital signal is sequentially subjected to adaptive wavelet transform denoising and empirical mode decomposition to obtain a multi-level intrinsic mode function set, an intrinsic mode function of a characteristic frequency band is extracted from the multi-level intrinsic mode function set, and the signal is reconstructed. Introducing a dual noise reduction mechanism combining adaptive wavelet transform and empirical mode decomposition; a signal quality real-time evaluation system is established, and system parameters including the gain of a variable gain amplifier and the bandwidth of a dynamic band-pass filter are dynamically adjusted through closed-loop feedback. The self-adaptive optimization of the whole biopotential signal acquisition process is realized, various interferences are effectively inhibited, the signal characteristics are reserved, and the signal-to-noise ratio is remarkably improved.

The invention discloses a self-adaptive circuit, a self-adaptive method and an optical module. The circuit comprises a control module and a laser driving module, the laser driving module comprises a variable gain amplifier VGA and a continuous time linear equalizer CTLE; the control module is used for comparing the first voltage signal with a preset threshold voltage signal to obtain a comparison result; based on the comparison result, a control signal is sent to the laser driving module; wherein the first voltage signal is obtained by performing statistical analysis on a stored digital signal by the control module; the control signal is used for controlling the laser driving module to adjust register settings of the VGA and the CTLE; the laser driving module is used for adjusting register settings of the VGA and the CTLE based on the control signal; wherein registers of the VGA and the CTLE are adjusted to different register values.

The present invention relates to a duobinary signal reception device and method in which: a variable gain amplifier (VGA) amplifies a duobinary signal; a duobinary-to-non return to zero (NRZ) converter restores an NRZ signal on the basis of a differential signal of the amplified duobinary signal and a predetermined reference voltage signal; a digital regulator voltage (DRV) circuit outputs the restored NRZ signal; and the duobinary-to-NRZ converter comprises an exclusive OR (XOR) gate to which the differential signal of the amplified duobinary signal is input, and a comparator to which an output of the XOR gate and the reference voltage signal are input.

The invention discloses a high-speed serial signal linear equalization circuit which comprises an input terminal, a continuous time linear equalizer (CTLE), a super source follower, a variable gain amplifier (VGA) and an adaptive feedback. The input end is connected with a 100-ohm internal resistance differential signal source of the transmitting end through a channel; the equalization circuit CTLE is connected to the output end of the input end connection module, two groups of resistance switches (RsMF and RsHF) of the CTLE module are respectively controlled by 4-bit binary codes to enable source degeneration resistors Rs of two stages of CTLEs to be variable, two groups of capacitance switches (CsMF and CsHF) are respectively controlled by 2-bit binary codes to enable source degeneration capacitors Cs of the two stages of CTLEs to be variable, and the two groups of capacitance switches (CsMF and CsHF) are respectively controlled by 2-bit binary codes to enable source degeneration capacitors Cs of the two stages of CTLEs to be variable. The change of a zero pole of the circuit is realized through the change of the source degeneration resistor Rs and the source degeneration capacitor Cs, and the adjustability of the difference between the high-frequency gain and the low-frequency gain of the circuit is realized, so that the multi-gear adjustability of the equalization capability is realized.

A beamforming front end (BFFE) for a receiver performs beamforming without needing to perform phase-shifting on each of a plurality of received signals. The BFFE comprises first variable gain amplifiers (VGAs) that respectively amplify the received signals by first gain values and second VGAs that respectively amplify the received signals by second gain values. Outputs of the first VGAs are combined into a first combined signal, and outputs of the second VGAs are combined into a second combined signal. The first and second combined signals are then used to produce an output signal corresponding to phase-shifting the received signals by amounts corresponding to the respective first and second gain values and then summing the results of the phase shifting. The output signal may be produced by mixing the first combined signal with an in-phase local oscillator signal and mixing the second combined signal with a quadrature local oscillator signal.

The invention discloses an LPO wired receiver adopting adaptive CTLE based on a genetic algorithm, and the receiver comprises an analog front end, a data sampler, an edge sampler, an error sampler, a 1: 32 demultiplexer, a verification module, an eye pattern monitor, a genetic algorithm module, clock recovery logic, and a clock path. The eye pattern monitor is used for calculating the eye pattern closure degree according to the data of the data sampler and the error of the error sampler and outputting the eye pattern closure degree to the genetic algorithm module; and the genetic algorithm module is used for realizing parameter adaptive control of a continuous time linear equalizer CTLE and a variable gain amplifier VGA in the analog front end. The invention aims to apply the genetic algorithm to the adaptive equalization of the adaptive continuous time linear equalizer, so that the adaptive continuous time linear equalizer has stronger global search capability and lower power consumption and is not easy to fall into local optimum, and the complexity and power consumption of the adaptive continuous time linear equalizer are reduced. And the real-time and energy-saving requirements are met.

The invention provides an automatic gain control method and circuit of an ultrasonic flow metering device, and aims to improve the accuracy and stability of flow metering. According to the method, the gain is automatically adjusted by measuring the pulse width of an echo signal and comparing the pulse width with an expected value. The circuit comprises a transmitting circuit, an ultrasonic transducer, a variable gain amplifier, a variable threshold comparator, a zero-crossing comparator, a flight time measuring unit, a pulse width measuring unit, a time-to-digital converter and a calculation and control unit. According to the scheme, independent gain configuration of uplink and downlink flight time and a fine gain adjustment strategy based on echo amplitude change can be realized. In addition, by setting the allowable maximum pulse width change value, whether the measurement error is within a reasonable range can be automatically judged, and re-measurement can be carried out when necessary. According to the integrated design scheme, the flexibility and the response speed of measurement are improved, the signal processing flow is optimized, and an innovative solution is provided for ultrasonic flow metering.

The invention provides an ultra-wideband bidirectional active phase shifter based on reconfigurable PPFs, and belongs to the technical field of microwave radio frequency, the bidirectional active phase shifter adopts a symmetrical structure, and comprises two groups of single-ended to differential ultra-wideband Marchand baluns, two two-order reconfigurable PPFs, four bidirectional variable gain amplifiers and a digital control module; wherein the PPF adopts a two-order adjustable resistor and adjustable capacitor structure, the bandwidth can be expanded to realize the ultra wide band, and when the phase shifter carries out steering operation, the impedance is changed due to switching of a switch, so that an error is introduced, and the impedance is adjusted and the error is reduced by adjusting the resistor and the capacitor. According to the phase shifter, the advantages of an active phase shifter and a passive phase shifter are combined, the area can be further reduced while bidirectional phase shifting operation is achieved and the phase shifting precision is guaranteed, and the problems that a traditional active vector synthesis phase shifter can only conduct unidirectional phase shifting operation, and the area of a passive phase shifter is large are solved.

A phased-array transmitter system includes a plurality of signal paths and a power amplifier. Each of the signal paths comprises: a phase-shifter configured to generate a phase-shifted signal; a first mixer configured to mix the phase-shifted signal with a baseband signal to generate a first mixed signal; a variable gain amplifier (VGA) configured to perform phase-invariant gain-controlled amplification on the first mixed signal; a second mixer configured to mix the amplified first mixed signal with a radiofrequency local oscillator (RFLO) signal to generate a radiofrequency (RF) signal; and a power amplifier configured to amplify the RF signal and feed the amplified RF signal to an antenna.

The invention discloses an MEMS resonator low ripple error temperature measurement system based on voltage feedback compensation, and the system comprises a trans-impedance amplifier, an analog-to-digital converter, a frequency detection module, a PI controller, a variable gain amplifier, a Schmitt trigger, a first digital-to-analog converter, a biasing circuit, mode switches S1 and S2, and a voltage feedback compensation loop. The compensation loop comprises an amplitude detection module, a lookup table, a second digital-to-analog converter and an adder; the amplitude detection module receives the digital signal from the analog-to-digital converter and outputs a vibration amplitude signal in real time; the lookup table receives the vibration amplitude signal, inquires and outputs a corresponding digital compensation voltage, and converts the digital compensation voltage into an analog voltage through a second digital-to-analog converter; the adder adds the analog voltage and a fixed bias voltage to generate a dynamic bias voltage and applies the dynamic bias voltage to a drive electrode of the MEMS resonator. According to the system, an amplitude-driving end bias voltage feedback compensation loop is introduced, so that the periodic ripples of the resonant frequency are effectively suppressed.

Systems and methods for operating phased arrays are described. A circuit can receive an index associated with an antenna among a plurality of antennas in a phased array. The circuit can use the index to identify at least a phase value and a gain value of a known beam. The circuit can receive at least one static configuration of the antenna and at least one beam transformation parameter. The circuit can transform, based on the at least one beam transformation parameter and the at least one static configuration, the phase and gain values of the known beam into phase and gain values of a desired beam. The circuit can map the phase value of the desired beam to a phase shifter setting of the antenna and the gain value of the desired beam to a variable gain amplifier setting of the antenna to generate the desired beam.

Bidirectional variable gain amplifiers (VGAs) for radio frequency (RF) communication systems are provided. In certain embodiments, a bidirectional VGA includes a first amplifier having an input coupled to a transmit / receive port, a second amplifier having an output coupled to a transmit port, a third amplifier having an input coupled to a receive port, a fourth amplifier having an output coupled to the transmit / receive port and to the input of the first amplifier, and a switch circuit that connects an output of the first amplifier to an input of the second amplifier in a transmit mode, and that connects an output of the third amplifier to an input of the fourth amplifier in a receive mode.

The invention specifically discloses an ultrasonic guided wave edge real-time communication method and system based on an FPGA (Field Programmable Gate Array), and the method comprises the following steps: the FPGA of a guided wave communication transmitting circuit receives data needing to be transmitted, completes the data package construction and carrier modulation, and outputs a digital signal; after digital-to-analog conversion, a multi-stage power amplification circuit and a matching network circuit, the ultrasonic guided waves are transmitted to an excitation piezoelectric transducer, and the excitation piezoelectric transducer generates ultrasonic guided waves to be transmitted in a metal medium; the receiving piezoelectric transducer converts ultrasonic guided waves transmitted in a metal medium into piezoelectric signals, the piezoelectric signals sequentially pass through the active filter circuit, the variable gain amplification circuit and the analog-to-digital conversion circuit and are transmitted to the FPGA of the guided wave communication receiving circuit in the form of digital quantity, and the FPGA operates a demodulation algorithm to restore effective binary data. And the data is transmitted to other equipment. According to the technical scheme, the FPGA serves as a processing unit, high-frequency carrier modulation and real-time operation of a complex demodulation algorithm can be completed, and the high-speed communication requirement can be met.

The invention provides an on-chip calibration source circuit and a chip for a radio frequency direct acquisition receiving link, the on-chip calibration source circuit comprises a clock signal output circuit and a differential current signal output circuit, the output end of the clock signal output circuit is connected with the input end of the differential current signal output circuit; the output end of the differential current signal output circuit is movably connected with the input end of the variable gain amplifier; the clock signal output circuit is used for outputting a clock signal to the differential current signal output circuit; the differential current signal output circuit is used for generating a first calibration signal according to an input clock signal and outputting the first calibration signal to the variable gain amplifier, and the first calibration signal is a differential current signal; the first calibration signal is used for performing error calibration on the variable gain amplifier; the variable gain amplifier is used for outputting a second calibration signal to the time-interleaved analog-to-digital converter according to the first calibration signal; the second calibration signal is used for performing error calibration on the time-interleaved analog-to-digital converter.

The invention discloses a multi-channel multi-band universal intermediate frequency receiving and processing device, which relates to the field of communication and comprises a switch, a splitter, a variable gain amplifier, a temperature compensation attenuator, an amplifier, a filter, a frequency synthesizer, a frequency mixer, a numerical control attenuator, an FPGA (field programmable gate array) processor and the like. The system has the advantages of miniaturization, low power consumption, low cost, high jump speed, multiple channels, multiple frequency bands, full localization, high environment adaptability and the like, and can meet the application requirements of various working scenes such as a fixed station, a vehicle-mounted station, an airborne station, a portable station and the like. Rapid frequency hopping, multiple frequency bands, multiple channels and 100% localization are the key of the invention. Through the multi-channel and multi-frequency-band design, a plurality of independent receiving channels can be realized, a plurality of intermediate frequency working frequency bands such as 70MHz, 140MHz and extended L frequency bands are supported at the same time, and the universality and the integration degree of the intermediate frequency receiving channels are remarkably improved.

The invention discloses an impedance-invariant vector synthesis phase shifter, an array element and a phased array, and relates to the technical field of phased array design. According to the impedance-invariant vector synthesis phase shifter provided by the invention, two capacitive compensation branches are arranged in each Gilbert unit of a variable gain amplifier, and the capacitive compensation branches are connected to a circuit only when bits are turned off, so that the output impedance of the unit is kept unchanged when the bits are turned on and turned off, and the output impedance of the unit is not changed when the bits are turned off. The phase shifting precision of the phase shifter is effectively improved, the root mean square phase error of the phase shifter is reduced to be within the acceptable range of the engineering field, phase shifting is directly carried out according to the most ideal condition based on IQ orthogonal signals, complicated calibration work is avoided, and the calibration problem of the vector synthesis phase shifter is solved. The invention further provides an array element which adopts the impedance-invariant vector synthesis phase shifter, the continuous time linear equalizer and the current mode attenuator and has the advantage of being convenient to deploy.

The embodiment of the utility model provides a bidirectional variable gain amplifier and a bidirectional phase shifter. The bidirectional variable gain amplifier comprises a forward node and a reverse node, the first variable gain unit is used for providing variable gain when the forward node inputs a radio frequency signal; the input end of the first variable gain unit is connected with the forward node; the first switch unit is used for connecting or disconnecting the forward node, the input end of the first variable gain unit and a first path between the output end of the first variable gain unit and the reverse node; the second variable gain unit is used for providing variable gain when the reverse node inputs the radio frequency signal; the input end of the second variable gain unit is connected with the reverse node; and the second switch unit is used for connecting or disconnecting the reverse node, the input end of the second variable gain unit and a second path between the output end of the second variable gain unit and the forward node.

A phased array transmitter system includes a plurality of signal paths and a power amplifier. Each of the signal paths includes: a phase shifter configured to generate a phase shifted signal; a first mixer configured to mix the phase shifted signal with a baseband signal to generate a first mixed signal; a variable gain amplifier (VGA) configured to perform a phase-invariant gain-controlled amplification of the first mixed signal; a second mixer configured to mix the amplified first mixed signal with a radio frequency local oscillator (RFLO) signal to generate a radio frequency (RF) signal; and a power amplifier configured to amplify the RF signal and feed the amplified RF signal to the antenna.

The invention discloses a variable gain power amplifier architecture with low phase error and high rollback efficiency, and belongs to the technical field of radio frequency front ends. Comprising a first transformer, a variable gain amplifier module, a second transformer, a power amplifier module and a coupling line output matching network, the coupling coefficient of the first transformer is k1, and the coupling coefficient of the second transformer is k2; each of the variable gain amplifier module and the power amplifier module comprises two self-adaptive bias modules, and the bias state of the power amplifier module is adjusted through the self-adaptive bias modules, so that the power additional efficiency and the linearity of the power amplifier module are improved; the phase change is offset by simultaneously adjusting the control voltage of the variable gain amplifier module and the grid voltage of the adaptive bias module. Due to good phase error, high output power and high rollback efficiency, the antenna is suitable for a millimeter wave phased array transmitter.

Systems and methods for intelligent re-drivers capable of link monitoring and link training in accordance with embodiments of the invention are illustrated. A re-driver in accordance with a first embodiment includes a programmable linear equalizer capable of equalizing a transmitted analog signal to generate an equalized signal, and a variable gain amplifier capable of amplifying the equalized signal to produce an amplified signal. The re-driver further includes a line driver capable of generating an output signal based upon the amplified signal, and digital link adaptation circuitry that is capable of sampling the amplified signal to produce a sampled signal, generating programming parameters for the programmable linear equalizer based upon the sampled signal, and programming the programmable linear equalizer.

To provide a system and a method for accurately detecting recovery from the loss of a signal in an optical receiver.SOLUTION: An optical device, which is part of an optical receiver 310, comprises: a photodiode 311 configured to receive optical signals; and a linear trans-impedance amplifier (TIA) 312 having an input stage 313, an output stage 315, and at least one variable gain amplifier (VGA) 314 provided between the input stage and the output stage. The optical device also comprises: an automatic gain control loop 331 configured to rectify an output of the at least one VGA and compare the rectified output with a threshold gain setting to generate an automatic gain control voltage; and a detection circuitry 330 being configured to detect a rate of change in the automatic gain control voltage and being configured to determine a first state indicative of an absence of the optical signals at the photodiode. At least in response to the determined first state, the detection circuitry is configured to disable the output stage of the linear TIA.SELECTED DRAWING: Figure 3

The invention relates to the technical field of wireless communication, and provides a low-noise down-conversion signal processing method and system, and the method comprises the steps: collecting an I / Q baseband signal, carrying out the processing of a signal branch and a mirror image branch of a dual-branch decoupling convolutional neural network, and obtaining a signal feature vector and a mirror image feature vector; decomposing the feature vector into a real part, an imaginary part, amplitude and phase components, and constructing a state vector by combining temperature, frequency and device parameters; inputting the state vector into a radio frequency sensing deep reinforcement learning network to output a gain control strategy; environment change is monitored through the meta-learning network, and network weight is adjusted based on performance feedback; and regenerating a final gain control strategy by using the updated weight, controlling the variable gain amplifier to carry out gain adjustment on the I / Q signal, and outputting a signal after low-noise gain control. According to the invention, low-noise, high-precision and adaptive gain control processing of I / Q baseband signals in a complex radio frequency environment is realized, and the signal-to-noise ratio and control precision of down-conversion signals are improved.

The invention discloses a high-precision calibration amplitude-phase control device and a transceiver, the amplitude-phase control device and the transceiver are composed of one or more circuit devices of a phase shifter, an attenuator, an amplifier, a power combiner, a power divider and a transceiving switch, and a high-precision calibration circuit of the amplitude-phase control device comprises a calibration adjustment unit. The calibration adjusting unit is composed of one or more of a resistance network, a capacitance network, an inductance network, a transistor network and a switch element network. An adjustable resistance network is introduced into a phase shifter orthogonal signal generation circuit, an adjustable capacitance network is introduced into a variable gain amplifier of the attenuator, performance parameters of the phase shifter and the attenuator are adjusted by regulating and controlling the resistance network and the capacitance network, an amplitude-phase control device and a transceiver are regulated and controlled through a calibration adjustment unit, and the amplitude-phase control device and the transceiver are adjusted and controlled through a calibration adjustment unit. And high-precision calibration and optimization of performance parameters of the amplitude-phase control device and the transceiver are realized.

The invention provides a gain-reconfigurable active phase shifter with a low phase error, and relates to the technical field of phase shifters, and the phase shifter comprises a quadrature coupler which converts a radio frequency input signal into a shunt radio frequency signal; the input matching Balun converts the shunt radio frequency signal into a shunt differential signal; the digital control signal received by the phase inversion variable gain amplifier is used for controlling the on-off state of a differential pair in each differential group, and determining a differential combination current corresponding to a differential pair combination in a conduction state based on a shunt differential signal corresponding to each differential pair; the differential combination current is used for representing a gain state corresponding to the differential pair combination; the input impedance and the output impedance of the phase inversion variable gain amplifier in different gain states are kept unchanged; the vector synthesis module determines a phase shift differential signal based on the differential combined current; the output matching Balun converts the phase shift differential signal into a radio frequency output signal. The antenna has a wide gain adjustable range and a low phase error.

The utility model discloses a channel processing module based on an HF / VHF dual-band autonomous frequency selection communication system, which comprises an antenna feeder unit, a radio frequency receiving channel, an MCU module, a frequency transmitting channel and a post-stage power amplifier unit which are sequentially connected, the front end of the radio frequency receiving channel is provided with a high-speed numerical control sub-band filter, and the channel processing module is also provided with an AGC composed of an LNA, a fixed attenuator and a step attenuator. The LNA and the fixed attenuator form-10dB,-20dB, 0dB and + 15dB gain attenuation circuits, the AGC controls two SP4T to switch, the stepping attenuator is a digital control variable 1dB stepping attenuator, the transmitting frequency path is provided with an ALC formed by a voltage-controlled variable gain amplifier and a low-distortion amplifier, and the variable gain amplifier provides-14dB-+ 17dB radio frequency signal adjustment. According to the utility model, a zero intermediate frequency scheme is adopted, signals are directly converted from RF to baseband, intermediate frequency modulation is not needed, the circuit is simple, the control is flexible, the stability and reliability are high, the development and production cost is low, the circuit can be used after assembly, and repeated debugging is not needed.

The invention discloses a hybrid control variable gain amplifier without a decoder and a circuit of the hybrid control variable gain amplifier. The hybrid control variable gain amplifier comprises an OPA amplifier and two CMOS arrays connected with the OPA amplifier through a switch C1 and a switch C2. The hybrid control variable gain amplifier is switched from an analog control mode to a digital control mode by closing the switches C1 and C2. According to the circuit of the hybrid control variable gain amplifier without the decoder, circuits of two groups of CMOS arrays are respectively connected with a circuit of an OPA amplifier through a switch C1 and a switch C2; a circuit of the CMOS array is formed by connecting circuits of n + 1 gain blocks in parallel. A decoding module is not needed, delay can be effectively reduced in application needing extremely high-speed response, and compared with a traditional hybrid control variable gain amplifier, the hybrid control variable gain amplifier has the advantages of being relatively simple in structure, low in complexity, higher in analog control flexibility and wide in application.

The invention relates to the technical field of amplifiers, in particular to a variable gain amplifier with a wide linear gain range and a working method, and the variable gain amplifier comprises the steps that a linear gain generation circuit receives a differential input signal and provides gain-adjustable differential output based on linear control voltage; the linear gain generation circuit comprises at least one stage of variable gain unit which comprises differential input pair transistors MN1 and MN2. The load resistor elements R1 and R2 are connected between the power supply voltage VDD and the drain electrodes of the differential input pair transistors MN1 and MN2; the tail current source MN3 provides bias current for the differential input pair transistors MN1 and MN2; the active load network is connected between the drain electrodes of the differential input pair transistors MN1 and MN2 and the ground; the active load network comprises a control tube MN8, the control tube MN8 works in a sub-threshold region, a grid electrode receives linear control voltage, equivalent impedance of the active load network is enabled to be in exponential change along with the linear control voltage through exponential I-V characteristics, and dB linear gain adjustment of the variable gain unit is achieved.

According to the non-intrusive high-frequency magnetic field sensing data acquisition method based on the high-bandwidth acquisition range, the integrity of signals in the transmission process is ensured through the broadband matching network optimization technology, reflection and attenuation are reduced through impedance matching and loss compensation, the dynamic gain control technology is used for coping with the characteristic that the amplitude change of broadband signals is large, and the high-frequency magnetic field sensing data is acquired. Real-time gain adjustment is realized by using a series variable gain amplifier and an intelligent control algorithm, analog signals are acquired by a digital signal processing enhancement technology and then are converted into digital signals through a high-speed ADC, and the digital signals are processed in real time by using an FPGA; the self-adaptive filtering algorithm further improves the signal quality, filter parameters can be dynamically adjusted to adapt to noise characteristics of different frequency bands, the multi-sensor data fusion technology integrates data of a plurality of sensors, and high-precision non-intrusive measurement can be achieved in a wider frequency range.

To provide an apparatus and a method for transceivers.SOLUTION: In a first aspect, an observation receiver is implemented to detect common-mode local oscillator (LO) leakage while the observation receiver performs other functions. In a second aspect, a transceiver is implemented with an LO leakage compensation circuit that compensates a transmitter for LO leakage using a digital filter, such as a Kalman filter, that combines differential LO leakage observations with common-mode LO leakage observations. In a third aspect, a transmitter includes multiple local loopback paths including a first loopback path after a variable gain amplifier (VGA) and a second loopback path before the VGA.SELECTED DRAWING: Figure 1

To provide an apparatus and a method for transceivers.SOLUTION: In a first aspect, an observation receiver is implemented to detect common-mode local oscillator (LO) leakage while the observation receiver performs other functions. In a second aspect, a transceiver is implemented with an LO leakage compensation circuit that compensates a transmitter for LO leakage using a digital filter, such as a Kalman filter, that combines differential LO leakage observations with common-mode LO leakage observations. In a third aspect, a transmitter includes multiple local loopback paths including a first loopback path after a variable gain amplifier (VGA) and a second loopback path before the VGA.SELECTED DRAWING: Figure 1