677 results about "Input impedance" patented technology

The invention discloses a column type distribution transformer winding abnormity detection system and detection method. The detection system comprises a frequency response detection instrument, a signal coupling assembly, an impedance matching module and a data processing module. The frequency response detection instrument is used for outputting a frequency sweep excitation signal and collecting a winding response signal; the signal coupling assembly is used for isolating power frequency voltage and filtering low-frequency interference; the impedance matching module is used for adjusting output impedance and input impedance to realize matching with electrical characteristics of different windings; and the data processing module is used for constructing an equivalent detection loop model, completing frequency response simulation calculation and carrying out frequency domain analysis and anomaly identification on an actually measured response curve. According to the invention, electrified state diagnosis of distribution transformer winding structure abnormity (such as deformation and loosening) can be realized.

The invention relates to the technical field of wireless communication networks, and provides a low-channel electroencephalogram amplification circuit and brain-computer interface equipment oriented to an after-ear electroencephalogram signal, and the low-channel electroencephalogram amplification circuit comprises a dry electrode sensing module which is used for collecting an electroencephalogram signal; the front active amplification module comprises an operational amplifier circuit with high input impedance; the anti-aliasing filtering module is formed by cascading a multi-order passive filtering network and an active filtering circuit, is connected with the output end of the front active amplification module and is used for filtering high-frequency interference signals; the right leg driving feedback module comprises a programmable impedance adjusting circuit and a current limiting protection circuit, the right leg driving feedback module and the front active amplification module form a closed-loop feedback loop, and the output end of the right leg driving feedback module and the human body form a current loop through a protection resistor; the analog-to-digital conversion module adopts an integrated low-power-consumption analog front-end chip; a wireless transmission module; and the power supply management module provides independent power supply for the analog front-end chip, the operational amplifier circuit and the wireless transmission module.

The invention relates to the technical field of antennas, in particular to a multi-level intelligent overheating protection system and method based on a gallium nitride module antenna. According to the method, a thermal load optimal migration path is analyzed based on a virtual thermal capacity network model, and an input impedance matching network of a target unit is synchronously tuned according to the thermal load optimal migration path to compensate beam phase distortion caused by thermal migration; and according to the boundary constraint condition of the real-time threat scene feature injection virtual thermal capacity network model, dynamically solving a game equilibrium solution of a thermal load migration path and a beam parameter tuning amount, and generating a thermal-radio frequency combined control instruction set. According to the method, full-process closed-loop control from thermal inertia characteristic analysis, thermal network modeling to thermal-radio frequency collaborative optimization is realized, so that the gallium nitride antenna system can intelligently plan an optimal thermal migration path and compensate thermally induced performance distortion in real time in a complex thermal environment and a threat scene, and finally dual optimization of heat dissipation efficiency and radio frequency indexes is achieved.

The invention provides a method for extracting equivalent parameters of a cavity resonant wireless power transmission system. The method comprises the following steps: S1, acquiring system input impedance spectrum data; s2, taking the input impedance spectrum data of the system as input, and utilizing a trained LSTM regression model to obtain a preliminary predicted value of an equivalent parameter of the system; s3, based on the preliminary prediction value of the equivalent parameters of the system, performing regression fitting by adopting a nonlinear fitting algorithm to obtain an accurate value of the equivalent parameters of the system; the system equivalent parameters comprise cavity internal resistance and cavity equivalent inductance of the resonant cavity and a mutual inductance value between the coil and the resonant cavity. The method has the advantages that equivalent parameters of the cavity resonant wireless power transmission system in all current mainstream modes can be effectively extracted; the NLS algorithm is prevented from convergence failure or falling into local optimum due to the fact that an initial value seriously deviates from a real value, and the fitting precision and stability are extremely high.

The invention discloses a sensor array acquisition system for detecting gas, and relates to the field of gas sensors. The sensor array acquisition system for detecting gas comprises a gas sensor array, a signal conditioning circuit, an analog-to-digital conversion module, a control module and a power supply module. According to the sensor array acquisition system for detecting the gas, the voltage follower circuit with high input impedance is adopted, so that the problem of attenuation during signal acquisition of a high-impedance sensor is effectively solved, and the signal acquisition precision is improved. Through the adjustable direct-current bias circuit and the differential amplification circuit, the dynamic adjustment of the measurement range is realized, the gas detection requirements of different concentration ranges can be met, and hardware does not need to be replaced. A constant-current driving chip is adopted to control a sensor heating circuit, heating current can be accurately set by adjusting external resistance, it is ensured that the sensor works at the optimal temperature, and the stability and response speed of the sensor are improved.

The invention discloses a cable defect detection method and device, and relates to the field of power equipment fault detection, and the method comprises the steps: generating N electric signals with different frequencies in a preset frequency range, inputting the electric signals into a target cable, testing the input impedance of the target cable under the N electric signals with different frequencies, the broadband impedance of the target cable in the frequency range is obtained; according to the broadband impedance, generating an impedance amplitude and an impedance phase of the target cable at each preset frequency point, and constructing an impedance matrix; inputting the impedance matrix into a fault classification model, and identifying and outputting the category of the target cable through the fault classification model; and if the target cable has a fault, extracting the resonant frequency with the maximum amplitude in the broadband impedance amplitude spectrum of the target cable, and determining the fault position of the target cable through a fault positioning model according to the resonant frequency with the maximum amplitude and the typical wave velocity of the target cable. According to the invention, the fault of the target cable can be automatically, quickly and accurately identified, and the fault position can be positioned.

Methods and apparatus for a signal isolator that mitigates the effects of CMTI strikes. In embodiments, a first die comprises a transmit module and the first die has a first voltage domain; and a second die comprises a receive module including a receive amplifier configured to receive from the transmit module a transmit signal that includes a differential signal and a common mode current. The second die may have a second voltage domain with the first and second die being separated by an isolation barrier. In embodiment, the receive amplifier includes a differential amplifier to receive the differential input signal from the transmit module; and a common mode module configured to sense the common mode current and sink or source the common mode current and minimize changes to an input impedance of the receive amplifier.

Aspects of the present disclosure provide a circuit configured to adjust an input impedance of an amplifier such as a low-noise amplifier. In certain aspects, the circuit is coupled to a node, wherein the node is between a first transistor and a second transistor of the amplifier. The circuit may include an inductor and a capacitor coupled in series, wherein the inductor is coupled with one or more load inductors of the amplifier through negative magnetic coupling.

A radio-frequency system including: a self-complementary antenna characterized by an input impedance substantially independent of signal frequency across an operational frequency band; a passive coupling device characterized by a characteristic impedance and configured to couple the self-complementary antenna to a signal generator and a set of signal processors; a resistive matching network electrically connected between the self-complementary antenna and the passive coupling device configured to match the characteristic impedance of the passive coupling device to the input impedance of the self-complementary antenna; and a back-coupling line characterized by a substantially constant group delay across the operational frequency band configured to electromagnetically couple the signal generator to the set of signal processors.

The invention discloses a cable high-frequency impedance characteristic analysis method based on bipolar trapezoidal wave excitation, and belongs to the technical field of power equipment state monitoring and fault diagnosis. In order to solve the problems of low test efficiency, insufficient high-frequency parameter modeling precision and weak anti-interference capability in cable high-frequency impedance characteristic analysis of a traditional sine wave excitation method, the method comprises the following steps: generating an odd-symmetry bipolar trapezoidal wave excitation signal with specific frequency and amplitude, and injecting the signal into the head end of a cable to be tested through a coupling device after power amplification; synchronously acquiring a high-frequency response signal of the key position of the cable under the excitation of the bipolar trapezoidal wave by using a data acquisition system; preprocessing the high-frequency response signal, converting the high-frequency response signal into a frequency domain through Fourier transform, calculating input impedance of the cable under different harmonic frequencies, and synthesizing a broadband impedance spectrum; based on the broadband impedance spectrum, the amplitude-frequency characteristic and the phase-frequency characteristic of impedance are analyzed, and cable state evaluation, partial discharge detection, insulation defect diagnosis or fault point positioning are realized. The method is used for an electric power system.

The present application discloses a low-cost and high-performance radio-frequency amplifier, comprising an input stage circuit, a common-gate stage circuit, and an output load circuit. The input stage circuit implements conversion from a single-ended signal to a differential signal, implements input impedance matching, and converts an inputted radio-frequency voltage signal into a radio-frequency current signal. The input stage circuit comprises a first three-coil transformer, consisting of a primary coil, a secondary coil, and a third coil. The common-gate stage circuit transmits the radio-frequency current signal outputted by the input stage circuit to the output load circuit, increases the withstand voltage and equivalent output impedance of the circuit, and implements gain control in at least two modes. The output load circuit converts the radio-frequency current signal from the common-gate stage circuit into a radio-frequency voltage signal, implements conversion from a differential signal to a single-ended signal, and outputs an amplified radio-frequency voltage signal. The present application provides a radio-frequency amplifier having a small size, broadband matching, high linearity, a large dynamic range, and low design complexity.

The invention discloses a dual-frequency compatible constant-current constant-voltage wireless charging system and a parameter tuning method thereof.The whole wireless charging system comprises a transmitting end and a receiving end, and the transmitting end comprises a direct-current voltage source Vdc, a high-frequency full-bridge inverter circuit, a primary side resonance compensation network and a transmitting coil Lp which are sequentially connected; and the receiving end comprises a receiving coil Ls, a secondary side resonance compensation network, a full-bridge rectification filter circuit and a direct-current load Ro which are connected in sequence. According to the invention, the hybrid compensation network is constructed in the system and parameter tuning is carried out on the hybrid compensation network, so that the resonant operation conditions of the system under two different frequencies can be met under the condition that inherent parameters of the system are not changed or complex control and additional devices are not used; on the basis, constant-current and constant-voltage hybrid wireless charging and input impedance zero-phase-angle operation can be achieved only through switching control over the two resonant frequencies, and the technical advantages of being high in efficiency, low in cost and easy to achieve are achieved.

The invention provides a radio frequency power division unit, a radio frequency power division module and a radio frequency receiving system. The radio frequency power division unit comprises a first low noise amplifier, a first single-pole single-throw radio frequency switch, a second single-pole single-throw radio frequency switch, a third single-pole single-throw radio frequency switch, a power divider, a fourth single-pole single-throw radio frequency switch and a fifth single-pole single-throw radio frequency switch; the input impedance of the input end of the power divider, the impedance of the first output end of the power divider and the impedance of the second output end of the power divider are all the same. According to the radio frequency power dividing unit in the embodiment, the impedance of the two output ends of the power divider can be completely matched with the input impedance of the transceiver connected with the rear stage of the power divider, so that the transmitted radio frequency energy cannot be reflected, and the maximum transmission of the radio frequency energy is realized.

The invention discloses a radio frequency matching method, a radio frequency matcher and a storage medium, which are used for solving the problems of matching dead zone and overlong time. Load impedance is detected through a load state sensor, input impedance is adjusted through an impedance adjusting network, and the impedance adjusting network comprises adjustable capacitors C1 and C2; and constructing a loss function L based on the modulus square of the reflection coefficient gamma, calculating the gradient and iteratively adjusting the capacitance parameter. The main control module drives the vacuum capacitor to continuously adjust, dynamic optimization is carried out in combination with a gradient descent algorithm, discrete limitation and dead zones of a traditional table look-up method are eliminated, pulse mode microsecond-level rapid matching is adapted, and radio frequency overshoot is restrained. The method improves the matching precision and speed under a dynamic load (such as plasma), gives consideration to the stability of a complex process, and is suitable for the technical processes of semiconductor etching and the like.

The utility model aims to provide the testing device based on the arm model heat flow, which is low in cost, can meet uv-level voltage testing requirements, can realize voltage testing of a plurality of channels, and can improve the testing efficiency. The device comprises an arm model, a heat flux sensor, a temperature sensor, an operational amplifier, an instrumentation amplifier, an analog-to-digital converter and a main control board, the heat flux sensor and the temperature sensor are both mounted on the surface of the arm model, the temperature sensor is mounted on the surface of a product, the temperature sensor is connected with the main control board, and the operational amplifier is connected with the main control board. The heat flux sensor is connected with the input end of the operational amplifier, the operational amplifier increases input impedance, the output end of the operational amplifier is connected with the input end of the instrument amplifier and amplifies and converts signals into differential analog signals, the output end of the instrument amplifier is connected with the 24-bit analog-to-digital converter, and the analog-to-digital converter is connected into an external upper computer through the main control board. The device is applied to the technical field of heat flux testing.

The invention discloses a broadband reflection amplification circuit design method based on a real frequency matching method, which comprises the following steps: firstly designing a reflection amplification circuit, designing a real frequency matching network based on the real frequency matching method, and finally inserting the real frequency matching network into the input end of the reflection amplification circuit to construct the broadband reflection amplification circuit based on the real frequency matching method. According to the method, the input impedance of the reverse amplification circuit is tested through the load traction technology, then the parameter characteristics of the matching network are calculated through the optimization algorithm, and finally the structure and parameter values of the matching network are obtained through the circuit synthesis method, so that the method is not limited by a specific matching network architecture, the performance of the matching network can be greatly improved, and the reliability of the matching network is improved. The problem of broadband matching between the transmitting-receiving antenna and the reflection amplification circuit is solved, so that the reflection amplification circuit can realize high gain under different input powers and input frequencies, the working bandwidth of the reflection amplification circuit is expanded, and the purpose of expanding the application scene of the reflection amplification circuit is achieved.

The invention relates to the technical field of wireless communication, and provides a power synthesis circuit and a power amplifier. Comprising a first signal input end, a second signal input end, an input impedance matching circuit, a first harmonic suppression circuit, a second harmonic suppression circuit, a first high-pass filter circuit, a second high-pass filter circuit, a low-pass filter circuit and a signal synthesis output end, the low-pass filter circuit comprises a first inductor, a second inductor and a first capacitor; the first end of the first inductor serves as the first input end of the low-pass filter circuit, the first end of the second inductor serves as the second input end of the low-pass filter circuit, the second end of the first inductor is connected with the first end of the first capacitor and the second end of the second inductor and serves as the output end of the low-pass filter circuit, and the second end of the first capacitor is grounded. The power synthesis circuit has the impedance conversion characteristic, and has the advantages of low cost, high isolation, high integration and the like.

The utility model provides a sampling circuit, an analog circuit and electronic equipment, and the sampling circuit comprises an input processing unit which is connected with the output end of a target circuit, and is used for collecting the common-mode output voltage of the target circuit, and carrying out the sampling input processing of the common-mode output voltage, and obtaining a first operational amplifier in-phase sampling signal and a first operational amplifier anti-phase sampling signal; the signal amplification unit is connected with the input processing unit and is used for respectively amplifying the first operational amplifier in-phase sampling signal and the first operational amplifier anti-phase sampling signal to obtain a second operational amplifier in-phase sampling signal and a second operational amplifier anti-phase sampling signal; and the signal stabilization unit is connected with the signal amplification unit and the control circuit, and is used for keeping the second operational amplifier in-phase sampling signal and the second operational amplifier anti-phase sampling signal, generating a feedback signal according to the second operational amplifier in-phase sampling signal and the second operational amplifier anti-phase sampling signal, and outputting the feedback signal to the control circuit. In this way, the input impedance and the sampling precision are improved.

The invention discloses an AFE analog front-end circuit applied to a multi-channel high-speed optical receiver. The circuit comprises an SF-TIA, a single-ended to differential circuit and a CLTE. The SF-TIA, the single-ended to differential circuit and the CLTE are connected in sequence; the SF-TIA is used for converting an input current signal into a voltage signal and transmitting the voltage signal to the single-ended to differential circuit; wherein the current signal is obtained by converting an input optical signal; the single-ended to differential circuit is used for converting the voltage signal into a differential voltage signal and transmitting the differential voltage signal to the CLTE; and the CLTE is used for compensating the high-frequency gain of the differential voltage signal to obtain a compensated voltage signal and outputting the compensated voltage signal. The amplifier has the advantages of being high in gain, low in power consumption, low in input impedance, low in noise, low in requirement for power supply voltage and simple in structure.

The invention discloses a power amplifier and circularly polarized antenna integrated structure which comprises a power amplifier and an antenna which are integrated together, and the antenna is a circularly polarized antenna. The input impedance of the antenna is directly matched with the output impedance of the power amplifier at the center frequency 1.9 GHz and the center frequency 2.6 GHz through the feed point position of the microstrip line in the antenna and the impedance of the microstrip line; the dual-frequency dual-band antenna has the advantages of being small in occupied size, high in integration level, small in transmission loss, high in transmission efficiency in high-frequency, broadband and high-power application scenes, capable of achieving dual-frequency work and capable of meeting the requirements of a wireless communication system for multi-frequency and high-quality transmission.

The present disclosure provides a plasma processing apparatus comprising: a plasma processing chamber; a substrate support; an electrode or an antenna; a radio frequency power supply; a power receiving coil electrically connected to the at least one power-consuming member; a power transmitting coil electromagnetically inductively coupled with the power receiving coil; a power transmitting unit electrically connected to the power transmitting coil to supply a power to the power transmitting coil; and a controller. The power transmitting unit includes a voltage detector and a current detector, and the controller is configured to determine a required power level corresponding to a parameter value including an input impedance obtained from the input voltage and the input current or a load resistance value of the at least one power-consuming member, and to control the power transmitting unit to output an output power having the required power level.

The invention discloses an optimization method of a butterfly-shaped UHF antenna, and the method comprises the following steps: determining a preset angle range of a semi-apex angle based on the matching relation between the characteristic impedance of the butterfly-shaped antenna and the working frequency band width, so as to achieve the stable change of the input impedance and the broadening of the frequency band; according to the wavelength of the low-frequency end of the working frequency band, a preset proportional relation between the arm length and the wavelength is established to determine the value of the arm length, so that the requirement of the antenna impedance bandwidth on low-frequency-band signal receiving is met; a butterfly antenna is arranged in a metal back cavity to form a back cavity type antenna, the height of the back cavity is determined according to the wavelength corresponding to the strongest frequency of a signal so as to suppress back radiation and enhance forward radiation gain, and systematic improvement of electromagnetic wave signal receiving performance is realized through collaborative optimization of structural parameters of the butterfly antenna and the back cavity.

The invention discloses a radio frequency power amplifier, a radio frequency power amplifier module and a radio frequency power amplifier module, and the radio frequency power amplifier comprises a four-stage power amplifier structure which is used for amplifying an input signal to preset output power; the inter-stage matching network is used for completing impedance matching between the output impedance of each stage of array and the output impedance of the rear-stage array and impedance matching between the input impedance of each stage of array and the output impedance of the front-stage array through an impedance matching technology; the protection circuit comprises a temperature protection unit and a standing-wave ratio protection unit. The temperature protection unit is used for monitoring the temperature of the GaN power amplifier unit in each array in real time and comparing the temperature with a preset temperature, and generating a logic instruction for cutting off the power supply of the corresponding array when the number of overtemperature units is judged to be greater than a preset number; the standing-wave ratio protection unit is used for detecting the output standing-wave ratio and generating a logic instruction for switching power supply when it is judged that the detected standing-wave ratio is larger than a preset ratio. According to the invention, high-performance communication requirements and simple and effective exception protection can be met.

The invention relates to a broadband impedance spectroscopy cable fault identification method and system and a storage medium, and the method comprises the steps: building a cable equivalent model according to any preset cable fault type; frequency sweep signals are input into the model, parameters of a cable core, a sheath and a steel armor under different frequency sweep signals are obtained, input impedance of the head end of the cable under different frequency sweep signals is calculated based on a cable modulus matrix and an input impedance formula, and a fault broadband impedance amplitude spectrum and a phase spectrum are drawn; repeating the steps to obtain a broadband impedance amplitude spectrum and a phase spectrum of the cable fault; the input impedance of an actual cable is collected in real time, a real-time broadband impedance amplitude spectrum and a real-time broadband impedance phase spectrum are drawn and compared with a cable fault broadband impedance amplitude spectrum and a cable fault phase spectrum, and the cable fault type and the distance between a fault point and the head end are recognized. Compared with the prior art, rapid cable fault identification and fault point determination are realized.

A method can include wireless circuits that, by operation of transmit switch circuits, include a transmit component in an output signal path between a transmit amplifier and an antenna port, the output signal path including a shared matching network. By operation of a transmit amplifier, an output signal can be generated for transmission over an output signal path to an antenna port. In a receive mode, by operation of the transmit switch circuits, an input impedance of the transmit component can be excluded from an input signal path between the antenna path and a receive amplifier. An input signal path can include the shared matching network. By operation of the receive amplifier, amplifying the received input signal. Corresponding devices and systems are also disclosed.

The invention belongs to the field of Tesla coil distribution parameter circuit model design, and discloses a Tesla coil distribution parameter circuit model based on half-wavelength segmentation. The model construction method comprises the following steps: (1) carrying out segmented modeling on a high-voltage coil according to wavelength; (2) respectively establishing a high-voltage winding circuit model and a low-voltage winding circuit model of the Tesla coil, and combining the complete Tesla coil circuit models; (3) calculating resistance, inductance, mutual inductance and capacitance parameters in the model by using an analytical expression; and (4) constructing a T parameter two-port network based on the established circuit model, and analyzing frequency characteristics such as input impedance and voltage gain. The model established by the invention can accurately analyze the frequency characteristic and the output characteristic of the Tesla coil, is wide in application range, can be applied to all specifications of Tesla coils, is high in model precision, small in error and high in operation speed, and expands the field in which a lumped parameter circuit model cannot be applied.

A bioimpedance measurement circuit for determining a corrected body impedance is disclosed having a set of terminals, a control circuit (200), an evaluation circuit (300), and a signal processing circuit (400). The control circuit (200) is configured to control: a measurement of body impedance (Zb) in which a stimulation current (iin) is applied through the first terminal and the second terminal, and an input voltage (vin) between the third terminal and the fourth terminal is measured; measuring a first body part impedance (Zw), in which a stimulation current (iin) is applied through the first terminal and the third terminal, and an input voltage (vin) between the first terminal and the third terminal is measured; and measurement of a second body part impedance (Zf), in which the stimulation current (iin) is applied through the second terminal and the fourth terminal, and the input voltage (vin) between the second terminal and the fourth terminal is measured. The signal processing circuit (400) is configured to determine an error impedance (Zerr) based on a measured first body part impedance (Zw), a measured second body part impedance (Zf), a stored first parasitic body part impedance (Zwp), a stored second parasitic body part impedance (Zf), and a stored input impedance (Zin), and determining a corrected body impedance (Zbcorr) based on the measured body impedance (Zb) and the error impedance (Zerr).

The invention discloses an underwater wireless transmission system multi-parameter online identification energy efficiency improvement method, which comprises the following steps: firstly, constructing a topological graph of an underwater wireless power transmission system, when the system works normally, acquiring voltage U1 and current I1 of a transmitting coil, and calculating input impedance; determining an equivalent circuit, and establishing an equation of a mutual inductor M, a bridging capacitor Ce and an equivalent load RLe through the voltage U1 and the current I1; and solving the mutual inductance M, the bridging capacitor Ce and the equivalent load RLe to realize multi-parameter identification. According to the technology, the driving frequency of a system does not need to be changed, a complex circuit does not need to be added, and the identification requirements of mutual inductance, bridging capacitance and load can be rapidly and accurately met. Afterwards, the working state of the system is judged according to the obtained bridging capacitance value, the method can accurately control the power and efficiency of the system, and the stability and reliability of the charging process are improved.

The invention discloses a system for simultaneously measuring residual voltage and discharge capacitance of an electric appliance plug. The system comprises a phase detection unit, a measurement control unit, an electronic disconnection unit and a multi-input impedance measurement unit. According to the system, a conventional residual voltage test is carried out once, plug discharge voltage curves at different moments can be obtained by using the high-impedance measurement unit and the low-impedance measurement unit, discharge time constants during high-impedance measurement and low-impedance measurement are respectively calculated through curve fitting, the optimal estimated values of discharge capacitance and discharge resistance are obtained, and the test accuracy is improved. And reversely calculating whether the action of the electronic circuit participates in the discharge process after the peak value is switched off, thereby achieving a primary electric appliance plug discharge test and obtaining three measurement parameters. Therefore, the system disclosed by the invention can be used for conformity judgment on whether the charged capacitor on the plug pin of the electrical product can cause the electric shock danger, and has the characteristics of accurate test, simple operation and the like.

A transmit (TX) local oscillator (LO) leakage calibration circuit, the circuit comprising: a transceiver having a transmit portion and a receive portion; an interface circuit connected to the transmitting portion and the receiving portion; an impedance control circuit connected to a low noise amplifier (LNA) in the receiving portion, the impedance control circuit configured to adjust an input impedance of the LNA; a power detector coupled to an output of the LNA; and a local oscillator cancellation element connected to the power detector, the local oscillator cancellation element configured to adjust an input of the transmit section based on a TX LO leakage detected by the power detector.