248 results about "Common mode noise" patented technology

The invention belongs to the technical field of wind power generation equipment state monitoring and intelligent fault diagnosis, and discloses a wind turbine generator blade acoustic fault detection method based on transfer learning, and the method comprises the steps: building a standardized sample through acoustic signal simulation and multi-dimensional data enhancement, and extracting weak fault features through an STFT-Mel frequency spectrum; a dual-scale time-frequency attention module is introduced into the lightweight MobileNetV3, so that the focusing and recognition capability on early crack features is improved; by combining transfer learning with MMD domain difference and entropy minimization regularization, efficient alignment of a simulation domain and actually-measured wind field data is achieved, and the generalization performance of the model under the small sample condition is enhanced; a transverse difference spectrogram and longitudinal historical baseline self-evolution double-flow feature fusion mechanism is adopted, common-mode noise is suppressed, and single-blade positioning, progressive degradation early warning and synchronous aging recognition are achieved. The method is small in parameter quantity, low in calculation overhead and suitable for high-precision and low-cost intelligent detection of early damage of the wind turbine generator blades.

The invention relates to the technical field of gas detection, in particular to a dual-wavelength-based adaptive methane detection method and system, and the method comprises the following steps: collecting environmental interference characteristics of a to-be-detected gas environment in real time; synchronously emitting a first laser beam and a second laser beam to a to-be-detected gas environment according to the tunable laser source; receiving optical signals of the first laser beam and the second laser beam and converting the optical signals into electric signals; calculating a light intensity difference value of the first laser beam and the second laser beam based on the electric signal to generate a differential absorption signal; performing optical differential compensation on the differential absorption signal, outputting a methane concentration value, and performing environmental drift compensation on the methane concentration value based on environmental interference characteristics; and performing real-time threshold value judgment on the methane concentration value, and if the methane concentration value exceeds a preset threshold value, triggering a local early warning signal. According to the invention, the problem that the detection precision is reduced due to the fact that methane absorption signal common-mode noise and absorption coefficient drift cannot be synchronously inhibited due to dust concentration and temperature and humidity interference in a dynamic complex environment under a mine is effectively solved.

The invention discloses an active pen and touch screen interaction system resistant to common-mode interference and a signal demodulation method. The system comprises a signal receiving terminal and a signal transmitting terminal. The signal transmitting terminal modulates data to be transmitted by adopting a differential binary phase shift keying modulation method, and transmits a generated modulation signal to the signal receiving terminal; the analog front-end receiving module is coupled with the signal transmitting terminal, receives the modulation signal and outputs a digital square wave signal after fidelity extraction processing; and the digital demodulation processing module performs differential coherent digital demodulation on the digital square wave signal based on the prior characteristics of the modulation signal, inhibits residual noise and recovers data to be sent. The analog front end focuses strong common-mode noise suppression and analog filtering, the digital demodulation algorithm performs secondary digital purification by using signal time sequence characteristics, and the two constructs an efficient anti-interference pipeline. Meanwhile, the regular square wave signals can be directly processed through differential coherent demodulation, and the requirements for performance and power consumption of a rear-end processor are lowered.

The invention relates to the technical field of amplifiers, and discloses an analog-to-digital converter combination instrument amplifier which comprises a first-stage amplifier, the first-stage amplifier is in signal connection with a second-stage amplifier, the second-stage amplifier is in signal connection with a front-end low-pass filter (LPF), the front-end low-pass filter (LPF) is in signal connection with an analog-to-digital converter (ADC), and the analog-to-digital converter (ADC) is in signal connection with the analog-to-digital converter. And an unbalanced input-to-balanced differential circuit output module is arranged between the second-stage amplifier signal and a front-end low-pass filter (LPF). From the perspective of signal processing and conversion, a precise signal transition bridge is constructed by adding an unbalanced input-to-balanced differential circuit output module, unbalanced signals output by a second-stage amplifier are converted into double-end balanced differential signals, common-mode noise interference is effectively resisted through a differential transmission mode, the signal purity is guaranteed, and the signal quality is improved. The front-end low-pass filter and the analog-to-digital converter are adaptive to differential signals, so that the signal transmission is stable and anti-interference, and the analog-to-digital conversion is more accurate.

An active compensation device including a first element group including an integrated sensing / compensation unit configured to generate a sensing signal corresponding to at least one of common-mode noise and differential-mode noise on at least two high-current paths, and a second element group including a compensation control unit including a negative impedance converter and configured to generate a compensation signal corresponding to the sensing signal and provide the compensation signal to the integrated sensing / compensation unit. The compensation control unit further including a stabilization unit configured to prevent oscillation caused by the sensed noise. The first element group and the second element group are mounted on a single substrate.

A noise reduction circuit includes: noise canceler circuitry configured to inject a compensation current into a power line and ground to reduce a common mode noise current that flows through the power line and the ground into a commercial power supply from a power converter with a switching element connected to the commercial power supply; and overcurrent inhibitor circuitry provided on a compensation current path through which the compensation current flows, the overcurrent inhibitor circuitry being configured to inhibit application of an overcurrent to the noise canceler circuitry.

The invention provides an epitaxial growth control method and device, computer equipment and a storage medium. The epitaxial growth control method comprises the following steps: irradiating a wafer to be measured and the surface of a reference irradiation surface by adopting a super-continuum spectrum laser light source to obtain a reflected light signal; synchronously scanning and filtering the reflected light signal to output two paths of narrow-band light; the two paths of narrow-band light are converted into electric signals and then differential operation is carried out, and the reflectivity of the wafer to be measured is calculated according to a differential result; and determining growth parameters of the epitaxial layer based on the reflectivity, and adjusting process parameters of the reaction cavity according to the growth parameters so as to control epitaxial growth of the wafer to be tested. According to the super-continuum spectrum laser light source, multiple characteristic wavelengths can be scanned in one process step, synchronous monitoring of multiple growth parameters is achieved, and the monitoring requirement of a complex epitaxial structure is met; in addition, common-mode noise in the measurement process is eliminated in real time through the double-beam differential measurement technology, the signal-to-noise ratio is greatly increased, the measurement precision is improved, and accurate control over epitaxial growth is achieved.

A common mode noise filter (1) according to an embodiment comprises: a first conductor part (3); a second conductor part (4); a first barrier layer (5) electrically insulated from the first conductor part (3); and a second barrier layer (6) electrically insulated from the second conductor part (4). The first conductor part (3) has a first spiral conductor (31) and a first lead-out conductor (32). The second conductor part (4) has a second spiral conductor (41) and a second lead-out conductor (42). The first barrier layer (5) is provided at a position at which the first lead-out conductor (32) and the outermost periphery (315) of the first spiral conductor (31) overlap when viewed in the vertical direction. The second barrier layer (6) is provided at a position at which the second lead-out conductor (42) and the outermost periphery (415) of the second spiral conductor (41) overlap when viewed in the vertical direction.

The invention provides an anti-interference pressure sensor signal conditioning circuit based on a differential amplification structure, and the circuit comprises a differential input module which is used for receiving a differential signal outputted by a pressure sensor, and carrying out the amplification and filtering of the outputted differential signal, and obtaining a first differential signal; the common-mode suppression module is electrically connected with the differential input module and is used for suppressing a common-mode signal in the first differential signal to obtain a second differential signal; the programmable gain amplification module is electrically connected with the common-mode suppression module and is used for performing programmable gain amplification on the second differential signal to obtain a third differential signal; the low-pass filtering module is electrically connected with the programmable gain amplification module and is used for filtering high-frequency noise in the third differential signal to obtain a fourth differential signal; and the output buffer module is electrically connected with the low-pass filtering module and is used for converting the fourth differential signal into a single-ended signal and outputting the single-ended signal. According to the invention, external electromagnetic interference and common-mode noise can be effectively suppressed, and the stability and accuracy of signal transmission are improved.

The invention provides a vehicle-gauge-level dynamic equalization SerDes system and a working method, and belongs to the technical field of high-speed serial communication, and the method is characterized in that the system comprises an environment feedback module which collects temperature, cable impedance and common-mode noise data in real time; the dynamic equalizer is used for adjusting parameters of the pre-emphasis, the continuous time linear equalizer and the decision feedback equalizer based on the data acquired by the environment feedback module; the link health monitoring unit is used for counting the bit error rate through a hardware counter and triggering a self-repairing process; and the repair controller is used for executing a self-repair process which comprises redundant channel switching, transmission rate degradation and link retraining operation. According to the invention, the hardware-level environment adaptive equalization and millisecond-level self-healing capability of the SerDes link can be realized, and meanwhile, the redundancy design cost is reduced.

The invention relates to the technical field of electric power facility monitoring, and discloses an electric power line detection system based on a three-dimensional inertial gyroscope and deep learning, which comprises a data acquisition module, a segmented preprocessing module, a trajectory resolving module, a trajectory correction module, a deviation analysis module and a risk early warning module. According to the application, the electromagnetic shielding and common-mode noise suppression technology is adopted to overcome high-voltage electromagnetic field interference, and the data acquisition quality is ensured; precise adaptation of different line features is realized through segmented adaptive preprocessing; inertial navigation error accumulation is effectively inhibited by utilizing topological constraint and multi-source data fusion; the problem of deviation identification under the small sample condition is solved by combining an attention mechanism and transfer learning; and finally, intelligent risk assessment and early warning are realized through deep reinforcement learning, so that whole-process intelligent processing from original data to risk assessment is realized, and the precision and efficiency of power line detection are improved.

A power converter can include a switching bridge having two input terminals that receive an input voltage and a switch node coupled to a primary winding of a transformer; at least one rectifier device coupled between a secondary winding of the transformer and an output of the power converter; and a common mode noise compensation capacitor. A first terminal of the common mode noise compensation capacitor can be coupled to a connection between the secondary winding of the transformer and the at least one rectifier device, and a second terminal of the common mode noise compensation capacitor can be coupled to one of the two input terminals. The common mode noise compensation capacitor can be coupled to an energized or a grounded input terminal. The common mode noise compensation capacitance can be selected to be equal to the turns ratio of the transformer times the parasitic capacitance of the transformer.

A dual tank LC-tuned Voltage Controller Oscillator (LC VCO) comprising a differential pair of cross-coupled transistors (M1, M2, M3, M4) produces a negative impedance by keeping a lower drain swing and a sufficient gate swing. The gate terminals of first and second transistors M1, M2 and third and fourth transistors M3, M4 are separated through a series of two inductors L1, L2 and two cross-coupled capacitors are connected between the drain and gate terminals of cross-coupled transistors to attenuate the output swing. The VCO tank further comprises two R2R Digital to Analog Converters (DAC) to bias both NMOS and PMOS cross-coupled pairs of transistors, to produce a common mode noise.

A resonant converter is provided. The resonant converter includes a primary circuit, an integrated transformer, a secondary circuit, a local ground, a first Y capacitor and a second Y capacitor. The primary circuit has a first positive line and a first negative line. The integrated transformer is electrically connected to the primary circuit. The secondary circuit is electrically connected to the integrated transformer and has a second positive line and a second negative line. The first Y capacitor is coupled between the local ground and the first positive line or the first negative line of the primary circuit. The second Y capacitor is coupled between the local ground and the second positive line or the second negative line of the secondary circuit. The first Y capacitor, the second Y capacitor and the local ground are configured to circulate common mode noise currents between the primary circuit and the secondary circuit.

Disclosed in the present invention is a filter circuit. A first PCB layer consists of a power line, a power interface, a second filter capacitor, and a first filter capacitor; the power line comprises a power supply network and a GND network; the second PCB layer is provided with a conductor plane; the power interface is connected to the GND network and is further connected to the conductor plane; the GND network, the second filter capacitor, and the conductor plane are sequentially connected; the power supply network, the first filter capacitor, and the conductor plane are sequentially connected. The circuit design of the circuit structure and the overall layout design idea in the present invention have a good suppression effect on common-mode noise, differential mode noise, radiation noise and conduction noise.

The invention provides a photoacoustic gas measurement method and a photoacoustic gas measurement system based on a series sensibilization technology, and relates to the technical field of optical gas sensing. The first-stage light absorption enhancement structure is used for carrying out maximum photoacoustic conversion on target gas to generate an initial photoacoustic pressure signal, the second-stage acoustic resonance structure is introduced to carry out resonance amplification on sound waves with specific frequency, a tandem cascade sensibilization framework of light absorption enhancement and acoustic resonance amplification is constructed, and through mutual verification analysis, the sensitivity of the target gas is improved. Calculating coherence outside preset noise analysis frequency band data, identifying and inhibiting common-mode noise interference caused by environment vibration and the like, generating feedback control parameters while calculating final gas concentration, adaptively adjusting intensity modulation frequency and wavelength modulation depth, and realizing high-precision and high-precision measurement. The measurement reliability, the dynamic range and the adaptive capacity of the system under complex working conditions are improved, and multiplier-level breakthrough of the sensitivity of the system and collaborative optimization of the performance are achieved.

This invention provides a planar transformer and a power conversion circuit, comprising a first composite winding layer, a second composite winding layer, a third composite winding layer, a fourth composite winding layer, and a primary winding, arranged sequentially from top to bottom. The first composite winding layer includes a first winding and a second winding; the second composite winding layer includes a third winding; the third composite winding layer includes a fourth winding; and the fourth composite winding layer includes a fifth winding and a sixth winding. The advantages of this invention are: it provides a planar transformer with a reasonable structure that can effectively suppress common-mode noise. This planar transformer does not have a shielding winding between the primary and secondary windings; by adjusting the structure of the secondary winding, it achieves the purpose of reducing common-mode noise, reducing the number of PCB layers, lowering production costs, and reducing debugging time, thus possessing good practical and application value.

The invention belongs to the technical field of EMI (Electro-Magnetic Interference) suppression, and relates to an EMI filtering method based on dual-frequency spread spectrum and dual-frequency recombination common-mode noise cancellation waveform, which comprises the following steps of: selecting a frequency as a composition frequency; enabling the EUT to work normally by taking a selected frequency as a switching PWM frequency, and obtaining common-mode noise amplitude data of multiple times of the frequency; acquiring a common-mode voltage amplitude, and calculating an amplitude transformation ratio and an amplitude of an injected offset waveform; acquiring a common-mode voltage amplitude, and calculating the phase of the injected offset waveform; injection offset waveform data is obtained through calculation, and the common-mode voltage is offset; according to the invention, common-mode noise is taken as a main scene, and common-mode suppression can be realized while the size is reduced.

This utility model discloses a frequency converter controller, including a control unit, a first filtering topology, and a second filtering topology. The first filtering topology includes a differential-mode inductor unit, and the second filtering topology includes a common-mode inductor unit. The first filtering topology is connected to the live wire, neutral wire, and protective ground wire, and receives the input signal from the power input terminal, suppresses the differential-mode noise and common-mode noise of the input signal from the power input terminal, and generates a first electrical signal. The second filtering topology receives the first electrical signal, suppresses the differential-mode noise and common-mode noise of the first electrical signal, and generates a second electrical signal. The control unit receives the second electrical signal. Because a differential-mode inductor unit is added to the first filtering topology, the number of magnetic rings can be reduced, the number of installation steps can be reduced, and costs can be optimized.

The invention provides a piezoelectric excitation out-of-phase vibration micro electric field sensitive structure, a sensor and a detection method. The sensor comprises the piezoelectric excitation out-of-phase vibration micro electric field sensitive structure, a substrate (6), an elastic beam (7), a piezoelectric driving unit (1) and a piezoelectric feedback unit (4), the piezoelectric excitation out-of-phase vibration micro electric field sensitive structure comprises an out-of-phase vibration unit (2) and a differential sensing unit (3). Induction electrodes of the differential induction units (3) are arranged on the substrate (6); the elastic beam (7) is connected with the substrate (6) and the out-phase vibration unit (2); the piezoelectric feedback unit (4) and the piezoelectric driving unit (1) at least comprise a piezoelectric material layer and two electrode layers, one end of the piezoelectric feedback unit (4) is fixed on the substrate (6), and the other end of the piezoelectric feedback unit (4) is connected with the elastic beam (7). According to the invention, differential detection can be realized, and crosstalk and environment common-mode noise in an alternating-current excitation signal can be effectively suppressed.

The invention relates to the technical field of aviation electric connectors, and discloses an isolation coupler, which adopts tin soldering to fix a shell and a shell cover so as to ensure the sealing performance and the stability of the shell and prevent the influence of external interference on signal transmission. And meanwhile, the shielding layers of the signal input lead and the signal output lead are welded with the shell, so that the anti-interference capability of signal transmission can be further improved. The circuit board assembly adopts the epoxy glass cloth board with the characteristic impedance of 77 ohms, so that the stability and the consistency of signal transmission can be ensured. Moreover, a leakage protection function is realized by adopting a single-point grounding structure of the first coupling transformer, a discharge path is provided for common-mode noise, the safety and reliability of the isolation coupler can be improved, and meanwhile, a ground loop can be cut off and power frequency interference can be eliminated by adopting a single-point grounding structure of the second coupling transformer, so that the accuracy of signal transmission is improved.

The invention relates to a three-phase single-stage isolation ACDC device and a server power supply, a three-phase single-stage isolation ACDC circuit is arranged on a substrate, a quiet potential assembly is arranged between the three-phase single-stage isolation ACDC circuit and a shell, and the quiet potential assembly is connected to the three-phase single-stage isolation ACDC circuit. And the first capacitor, the second capacitor and the third capacitor of the three-phase input circuit are connected to form a common end. Therefore, each moving point and the quiet potential assembly on the three-phase single-stage isolation ACDC circuit can be equivalent to a parallel plate capacitor, and after the three-phase single-stage isolation ACDC circuit operates in any phase and generates common-mode noise, common-mode current flows through the second end of the first capacitor, the second end of the second capacitor and / or the second end of the third capacitor through the equivalent capacitor, so that the common-mode noise is generated. And finally, the noise flows back to the noise source in the three-phase single-stage isolation ACDC circuit. Common-mode noise generated by the three-phase single-stage isolation ACDC circuit and the shell is avoided, and the purpose of improving and solving common-mode noise interference generated by the three-phase single-stage isolation ACDC circuit on adjacent electric equipment is achieved.

The present application relates to a communication device. A communication device having a common mode noise filter and improved heat resistance is provided. A communication device that performs data transmission based on a differential transmission method includes a first common mode noise filter including a first coil, a second coil, and a third coil; a communication control circuit that transmits and receives a signal through a first line connected to the first coil and a second line connected to the second coil; and at least one resistor disposed outside the first common mode noise filter, a first end of the resistor being connected to the third coil, and a second end of the resistor being grounded.

To provide a technique capable of suppressing differential mode noise in addition to common mode noise in a noise filter connected to a pair of power lines.SOLUTION: A noise filter disclosed in the present specification is a noise filter connected to a pair of power lines, and includes a first bypass capacitor connected between one of the pair of power lines and a ground, a second bypass capacitor connected between the other of the pair of power lines and the ground, a first resistive element connected in series with the first bypass capacitor, and a second resistive element connected in series with the second bypass capacitor.SELECTED DRAWING: Figure 2

The invention relates to a circuit and a method for measuring the threshold voltage of a PMOS (P-channel Metal Oxide Semiconductor) transistor in a radiation environment, in particular to an on-chip measuring circuit and a method for the threshold voltage of the PMOS transistor and a total radiation dose monitoring circuit, and solves the problem that the existing device for measuring the threshold voltage of the PMOS transistor cannot monitor the change of the threshold voltage on line. Or the size is large and the precision is low. According to the on-chip measuring circuit for the threshold voltage of the PMOS transistor, a differential mode is adopted, the subtracter circuit is used for sampling the voltage at the source end and the drain end of the PMOS transistor, common-mode noise generated by the outside to a measured signal can be effectively eliminated, the on-chip measuring circuit can be realized, the size and the weight of the measuring circuit are effectively reduced, and the cost is reduced. And real-time monitoring of the threshold voltage of the PMOS transistor is realized. Meanwhile, the invention further provides a total radiation dose monitoring circuit, signals are processed and amplified at the near end of the PMOS transistor, the strength and the anti-interference capacity of the measured signals can be effectively improved, and the size is further reduced.

An object is to provide a noise filter that can achieve high reliability. A noise filter includes: a noise detection unit which detects a common mode noise flowing through an electric path; an amplification unit which, on the basis of the common mode noise detected by the noise detection unit, generates a cancellation signal for canceling out the common mode noise; an injection unit which injects the cancellation signal into the electric path; an abnormality detection unit which detects abnormality of the noise filter on the basis of output voltage or output current of the cancellation signal, and outputs an abnormality detection signal; and a protection circuit which inhibits an abnormal cancellation signal from being injected into the electric path, on the basis of the abnormality detection signal.

The invention discloses a high-temperature dynamic strain test system and method, and relates to the technical field of high-temperature vibration test and strain measurement, and the system comprises a high-temperature loading measurement unit, a signal extension shielding line and a signal conditioning unit. The high-temperature loading measurement unit comprises a high-temperature strain measurement sheet and a compensation sheet which are respectively adhered to the tested piece and the accompanying test piece, and the high-temperature strain measurement sheet and the compensation sheet are in common-ground connection through a shielding layer by adopting a five-wire wiring method; the signal conditioning unit adopts a symmetrically-arranged double constant current source power supply and differential amplification structure, so that sensitivity deviation and common-mode noise interference caused by lead resistance change are effectively inhibited; according to the method, the maximum strain point is accurately positioned through the combination of finite element simulation and test, a dynamic resistance signal is directly converted by adopting constant-current excitation, and accurate acquisition of a strain signal in a high-temperature vibration environment is realized. According to the invention, the problems of obvious lead resistance influence and insufficient noise suppression capability in traditional measurement are solved, and high-precision and high-reliability measurement of dynamic strain of high-temperature parts such as aero-engine blades is realized.

The invention provides a camera triggering circuit, method, device and equipment. The circuit comprises a coupling circuit, a differential driving circuit and a camera driving circuit which are connected in sequence, the coupling circuit comprises an optical coupler, the input end of the optical coupler is connected with an initial single-ended signal, and the output end of the optical coupler outputs a TTL signal; the differential driving circuit comprises a differential line driver chip, the input end of the differential line driver chip is connected with a TTL signal, and the output end of the differential line driver chip outputs a differential signal; the camera driving circuit comprises a differential line connector chip and a switch element which are connected, the input end of the differential line connector chip is connected with a differential signal, the output end of the differential line connector chip outputs a trigger level, and the switch element is connected with the trigger level and outputs a signal for triggering camera driving. Therefore, the optical coupler is utilized to realize electrical isolation and block common-mode noise, and differential signals are utilized to improve the anti-interference capability in a complex electromagnetic environment, so that the anti-interference capability of the whole circuit can be remarkably improved.

The application provides a metal film thickness measurement method and device for tungsten gate chemical mechanical polishing, comprising a sensor probe, a power module, a signal excitation module, a differential amplification module, a synchronous demodulation module, a data acquisition and processing module; the sensor probe comprises coaxially arranged excitation coils, detection coils and balance coils; the signal excitation module drives the three-coil resonance module to induce eddy current effect at the metal film to be measured; the differential amplification module converts the equivalent impedance change caused by the eddy current effect in the coils into a differential signal, and simultaneously improves the dynamic range through low-noise amplification; subsequently, the synchronous demodulation module multiplies the differential signal with a reference signal, and extracts a direct current component proportional to the signal amplitude through a low-pass filter; the obtained voltage amplitude signal is input into the data acquisition and processing module; the application can significantly amplify the weak signal related to the film thickness, effectively suppress common-mode noise, obtain nanometer-level thickness resolution, and has a high signal-to-noise ratio.

The factory automation equipment (10) according to the present disclosure comprises a housing electrically connected to a frame ground (102), a signal circuit provided inside the housing and having a signal ground (202), a power extraction unit (11) electrically connected to the frame ground (102) and the signal ground (202) to extract power from common mode noise generated between the frame ground (102) and the signal ground (202), and an output unit (12) that outputs information relating to the power extracted from the power extraction unit (11) for display. (Representative diagram) Figure 1