58 results about "Passive filtering" patented technology

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 provides a defense device and method for a physical backdoor attack of a biological information identification system, and belongs to the field of information security. The biological information identification system is used for collecting and authenticating a multi-mode biological signal. The defense device comprises a coupling path blocking module which is used for cutting off or weakening the conduction of malicious noise in a physical connection path from three aspects of active shielding, passive filtering and voltage stabilization so as to guarantee the stability of a front-end physical environment. And the physical domain signal purification module forms a closed loop from real-time signal monitoring, feature analysis and interference suppression, and reduces noise transmitted from a power supply circuit to the acquisition device. And the numeric field semantic verification module is used for verifying the collected multi-mode biological signal and judging whether an abnormity or a backdoor injection attack sign exists or not. And the system control and management module is used for realizing communication between external equipment and each module and making a decision according to a numeric field semantic verification result. According to the invention, the physical interference signal injected into the back door can be effectively blocked, and the safety and reliability of the biological information identification system are guaranteed.

The invention relates to power semiconductor device on-line monitoring and power electronic system control, in particular to a SiC MOSFET conduction current extraction circuit and method, high-frequency oscillation interference is effectively suppressed through a second-order passive RC filter circuit, a measurement error less than or equal to 1.5% is realized within a current range of 50A-300A in combination with an accurate mathematical model established by a depth symbol optimization algorithm, and the measurement accuracy is improved. The requirement of the intelligent gate driver on high-precision current feedback is met, and the measurement precision is remarkably improved; the pulse width direct analysis technology is adopted, a traditional active integrator and a digital decoding link are omitted, the system response delay is smaller than or equal to 500 ns, microsecond-level over-current protection can be supported, the response speed and the real-time performance are optimized, and the system safety in a high-frequency application scene is remarkably improved.

The invention discloses a low-noise, high-precision and low-power-consumption tunnel magnetoresistance array type magnetic anomaly detection device, and relates to the field of geomagnetic field magnetic anomaly detection. In order to overcome the defects that in the prior art, the detection precision is insufficient, the noise level is high, power consumption is large, and long-time stable operation is difficult to consider, the technical scheme provided by the invention is that a signal acquisition and amplification circuit is composed of a plurality of triaxial tunnel magnetoresistive sensors, an isolation circuit, an instrument amplification circuit and a passive filter circuit; the master control and signal processing circuit is composed of a high-precision analog-to-digital conversion circuit, a clock circuit and a microprocessor circuit. The signal transmission circuit is composed of an Ethernet module and is used for transmitting the processed data to an upper computer; the power supply module is composed of a low-noise low-dropout voltage stabilizing circuit and a reference voltage circuit, and is used for providing a stable power supply and a unified reference voltage. The method is suitable for long-time high-precision geomagnetic anomaly detection work in geophysical exploration, national defense safety monitoring and complex environments.

The utility model belongs to the technical field of electronic circuit, especially relates to a passive low harmonic frequency converter special for rail transit air conditioner. The frequency converter includes: passive filter module, rectifier module, precharge module, voltage-sharing filter module, inverter module and control module. The input end of passive filter module is connected to the output end of alternating -current source, and the output end is connected to the input end of rectifier module, and the output end of rectifier module is connected to the input end of precharge module, the output end of precharge module is connected to the input end of voltage-sharing filter module, the output end of voltage-sharing filter module is connected to the input end of inverter module, and the output end of inverter module is the voltage output end of passive low harmonic frequency converter special for rail transit air conditioner, and inverter module and control module are connected through inverter control and protection circuit. The utility model can reduce the harmonic interference of frequency converter inverter to input power grid, protects the electrical equipment on power grid, and improves the security of operation.

The invention discloses a Ka-band satellite high-speed data transmission system, which adopts a Ka-band high-order modulation same-frequency dual-polarization ground high-speed data transmission design, adopts a system design method of high-order modulation, high-speed digital shaping, passive filtering and same-frequency dual-polarization transmission, and supports a double-frequency-point four-channel high-speed transmission mode. The bandwidth occupied by the system spectrum is further compressed, the transmission efficiency of the system is doubled under the strict constraint condition that the international electric connection Ka frequency band ground transmission carrier frequency meets the 1.5 GHz system bandwidth of 25.5 GHz to 27 GHz, and the frequency band utilization rate of ground transmission is effectively improved.

The utility model discloses an optical filter and a spectrograph, the optical filter (100) comprises multiple stages of passive filtering units (300), in two adjacent stages of passive filtering units (300), the output end of the previous stage of passive filtering unit (300) is connected with the input end of the next stage of passive filtering unit (300), and the output end of the next stage of passive filtering unit (300) is connected with the output end of the next stage of passive filtering unit (300). The passive filtering unit (300) is used for filtering and modulating an incident optical signal, so that the optical signal processed by the previous-stage passive filtering unit (300) enters the next-stage passive filtering unit (300), and the passive filtering unit (300) is used for filtering and modulating the incident optical signal; and the multiple stages of passive filtering units (300) are respectively used for modulating light with different wavelengths. The optical filter and the spectrometer provided by the utility model have the advantages of low power consumption and miniaturization.

The invention provides a multi-tuning composite passive filtering device and an intelligent switching control system and method thereof, and belongs to the field of passive filtering. The device comprises a plurality of groups of single-tuned filters and a group of C-type filters which are connected in parallel to a traction network, the front end of each branch is provided with a fling-cut switch which is used for cooperatively inhibiting multi-frequency harmonic waves and providing reactive compensation, and the system is used for controlling the switching of passive filters of each branch. By collecting system voltage, current of each branch, element temperature and switching state in real time and utilizing a digital signal processor to carry out fast Fourier transform and comprehensive state diagnosis, faults such as detuning, failure and overload of filter branches and the change trend of system harmonic waves can be intelligently judged; based on a diagnosis result, the system can automatically execute a protective removal or optimization switching strategy; according to the invention, upgrading from passive filtering to active early warning and intelligent treatment is realized, and the problem of system resonance risk possibly caused by filter performance reduction and continuous access is fundamentally solved.

The invention relates to the technical field of power supply filtering, and discloses a power supply filter with a signal masking function, which comprises a shell module for packaging each functional module and providing electromagnetic shielding; the passive filtering module performs primary filtering on a power supply signal to reduce low-frequency and intermediate-frequency noise; the signal sampling and spectrum analysis module samples and analyzes the frequency domain characteristics of the power supply signal, and extracts a target frequency band signal; the abnormal signal identification module identifies and judges abnormal coupling signals; the interference signal generation module generates a masking signal to suppress an abnormal signal; the closed-loop feedback control module adjusts parameters of the passive filtering and interference signal generation module in real time; and the output and verification module outputs and verifies the processed signal effect. The closed-loop feedback control technology is adopted, the technical effect of optimizing the system performance is achieved by monitoring the working state of the system in real time and dynamically adjusting the parameters of the filter and the interference signal module, and the defect that a traditional method cannot adapt to different working conditions in real time is overcome.

The present application relates to the technical field of wireless communication networks, and provides a low-channel EEG amplification circuit and a brain-computer interface device for behind-the-ear EEG signals, comprising: a dry electrode sensing module for acquiring EEG signals; a pre-active amplifier module comprising an operational amplifier circuit with high input impedance; an anti-aliasing filter module composed of a multi-order passive filter network and an active filter circuit in cascade, connected to the output end of the pre-active amplifier module, for filtering out high-frequency interference signals; a right leg drive feedback module comprising a programmable impedance adjustment circuit and a current limiting protection circuit, forming a closed-loop feedback loop with the pre-active amplifier module, and the output end of the right leg drive feedback module forming a current loop with the human body through a protective resistor; an analog-to-digital conversion module using an integrated low-power analog front-end chip; a wireless transmission module; and a power management module providing independent power supply to the analog front-end chip, the operational amplifier circuit, and the wireless transmission module.

The utility model relates to a three-phase input filter circuit, which comprises three multi-stage filter units and three discharge units, a, B and C phases of a power supply side are respectively connected with the three-phase bridge rectification unit through the three multi-stage filtering units; the A phase, the B phase and the C phase of the power supply side are respectively connected with the N phase of the power supply side through the three multi-stage filtering units and the three discharging units; according to the utility model, the three filtering units are arranged at the input side of the three-phase power supply, the three filtering units are used for filtering the three input phases of the three-phase power supply, i.e., the A, B and C phases respectively, the current harmonic pollution at the power grid side is reduced, the reactive power is reduced, the filtering circuit is introduced at the input side, and the harmonic pollution is eliminated through the passive filtering technology. Therefore, power quality is improved.

The application discloses a boost circuit capable of realizing adjustable charging and discharging frequency, comprising a charging and discharging circuit main body, three groups of optional passive RC filter circuits, a secondary passive filter and source follower circuit, a combination logic and differential pulse generation circuit and a negative feedback circuit. The charging and discharging circuit main body comprises two sub-circuits, the three groups of optional filter circuits are combined by switches and resistors and capacitors, and the negative feedback circuit controls the differential pulse signal by a comparator to adjust the charging and discharging. The circuit can realize the switching of three charging and discharging frequencies of 30 MHz, 100 MHz and 400 MHz, is stably boosted to 1.6 V-2.2 V, effectively controls dynamic noise and is suitable for application scenarios of low power supply voltage.

This invention proposes a design method for a full-band compact hybrid EMI filter circuit based on current feedback. The method includes: constructing an electromagnetic interference test circuit to obtain the common-mode EMI spectrum required for attenuation by the PWM converter, and establishing a high-frequency equivalent circuit for the PWM converter; obtaining the optimal hybrid EMI filter topology based on the high-frequency equivalent models of active and passive EMI filter circuits and the noise attenuation characteristics of the hybrid EMI filter circuit topology; designing the active EMI filter topology and its high-frequency equivalent model based on the noise cancellation principle of the active EMI filter and the common-mode EMI spectrum; designing the active EMI filter topology based on the noise cancellation principle of the active EMI filter and the common-mode EMI spectrum; designing the passive EMI filter structure based on the common-mode EMI noise spectrum after adding the active EMI filter; and designing the hybrid EMI filter circuit based on the hybrid EMI filter topology, the active EMI filter topology, the passive EMI filter structure, and the high-frequency equivalent models of the active and passive EMI filter circuits.

The embodiment of the invention relates to the technical field of direct current power supply, and discloses an active and passive hybrid filter circuit of a direct current bus. Comprising a passive filtering module, an active filtering module and a power supply module, and the power supply module is used for providing electric energy for the active filtering module; the passive filtering module is used for filtering interference signals on the direct-current bus by adopting a passive device; and the active filtering module is used for detecting current on the direct current bus by adopting an active device, outputting reverse injection current to the direct current bus and inhibiting interference signals on the direct current bus. The passive filtering module adopts CLC or LCLC filtering to suppress alternating current interference on the direct current bus, and the active filtering module adopts a current detection and current injection mode to offset direct current interference on the direct current bus, so that the direct current stability of the direct current bus is improved, and specified requirements are met.

The embodiment of the utility model provides a dynamic filtering compensation system and a low-voltage power distribution system, and the system comprises a passive filtering unit which is connected with the low-voltage power distribution system and is configured to output a first filtering current according to the harmonic wave of the first frequency of the low-voltage power distribution system; the monitoring unit is connected with the low-voltage power distribution system and is configured to output a compensation control signal for compensating the low-voltage power distribution system according to the electrical information of the low-voltage power distribution system; and the active filtering unit is connected with the monitoring unit and the low-voltage power distribution system and is configured to output compensation current to the low-voltage power distribution system according to the compensation control signal. Harmonic waves with specific frequencies can be basically filtered out through the passive filtering unit, the active filtering unit dynamically generates compensation current according to control signals of the monitoring unit, rapid and accurate compensation is carried out on the harmonic waves and reactive power, the problems that passive filtering is slow in response and inaccurate in control are solved, and parallel resonance can be effectively avoided.

The utility model belongs to the technical field of thickening agent processing equipment, and particularly relates to a filtering device for thickening agent processing, which comprises an equipment main body, a supporting pulley block, a sliding control table and a cylinder, the supporting pulley block is arranged at the upper end of the equipment main body, the sliding control table is arranged at the upper end of the supporting pulley block, and the cylinder is arranged at the upper end of the sliding control table. Through the arrangement of the sliding rail, the sealing cover, the spring column, the extrusion disc and the collection bin, when the equipment is used, an operator controls the air cylinder through the sliding control table, the operator firstly pours a thickening agent into the screen in the equipment main body, then closes the sealing cover and pushes the sliding control table, and then the thickening agent is squeezed out. The sliding control table slides on the sliding rail under the supporting of the supporting pulley block, so that the equipment can actively apply pressure to the filtering operation of the thickening agent, compared with a traditional passive filtering mode, the active pressure applying filtering can greatly improve the filtering speed of the thickening agent, the automation degree of the step is high, and extra labor cost does not need to be input.

A multi-band passive filtering circuit shaft voltage diagnosis and suppression device and method, which relates to the technical field of electrical equipment state detection and diagnosis, and solves the problem of how to measure and suppress abnormal shaft voltage under different operating conditions during the operation of a large generator; one end of an electrostatic effect discharge switch is connected in parallel with one end of multiple filtering frequency selection switches, the other end of the electrostatic effect discharge switch is connected to one end of a current-limiting resistor, and the other end of the current-limiting resistor is grounded; one end of a fuse is connected to the large shaft of the generator's excitation end, and the other end of the fuse is connected to the common point of the parallel connection of the electrostatic effect discharge switch and multiple filtering frequency selection switches; the other ends of multiple filtering frequency selection switches are respectively connected to the input ends of multiple passive band-pass filters, and the output ends of multiple passive band-pass filters are respectively connected to the common point of the connection between the electrostatic effect discharge switch and the current-limiting resistor; a voltmeter is connected in parallel across the current-limiting resistor; the circuit structure is simple, the measurement range is wide, it is convenient to find out the cause of abnormal shaft voltage, and the effective management of shaft voltage is realized.

The present invention provides an air conditioning apparatus provided with a radar sensor and a processing device, the air conditioning apparatus comprising: an active intervention module comprising: a passive filtering unit configured to filter coarse interference in detection data; the coarse interference comprises that the movement information coordinate exceeds a preset physical area, the collection time of the movement information exceeds a preset activity time period, and / or the movement information track exceeds a moving object of a preset track area, and establishing an original data set; the collection unit is configured to allocate suspiciousness for areas in the air-conditioned room based on the motion trail of the moving object in the original data set, and establish a suspicious area set according to a suspiciousness preset condition; the active filtering unit is configured to supply air to the suspicious area set when the moving object is not detected, and judge the moving object detected under the air supply condition as a passive interference source; and the active filtering unit takes the moving object after the passive interference source is filtered as an effective element. The method can improve the long-term accuracy of detection.

The invention discloses an intelligent self-cleaning oil smoke interception system based on a bionic cilium array, which realizes graded efficient interception of oil smoke particles through the bionic multi-stage cilium array, and integrates intelligent control modules for self-adaptive vibration cleaning, cilium surface functional modification and airflow and temperature collaborative sensing. The system can sense the oil smoke load and cilium pollution state in real time and dynamically adjust the cleaning strategy; a micro-nano composite structure super-oleophobic coating is constructed on the surface of the cilia; and meanwhile, auxiliary electrostatic adsorption and a local heat energy field are introduced, so that the capture rate of ultrafine particles is remarkably increased, and oil drop desorption is accelerated. The interception efficiency, the self-cleaning capability and the intelligence are remarkably improved, and the passive filtering mode of a traditional range hood is thoroughly changed.

The invention provides a signal processing method, a controller and a building control system, and relates to the technical field of building control. The method comprises the following steps: receiving a to-be-processed signal of a sensor, wherein the to-be-processed signal comprises a target signal and an interference signal collected by the sensor; analyzing the to-be-processed signal to determine an interference signal feature in the to-be-processed signal, the interference signal feature in the to-be-processed signal including at least one of a peak fluctuation feature and a waveform similarity feature; judging whether the to-be-processed signal contains a periodic interference signal or not according to the interference signal characteristics in the to-be-processed signal; and under the condition that the to-be-processed signal contains the periodic interference signal, the filter circuit is regulated and controlled according to the characteristics of the periodic interference signal. Through the method, the interference signal of the sensor signal can be accurately identified in real time, and filtering is performed in a targeted manner, so that the problems of sensor signal loss and non-ideal filtering effect caused by passive filtering can be solved.

The invention provides a high-resolution double-beam fundamental transverse mode semiconductor laser chip, and relates to the technical field of semiconductor lasers. The high-resolution double-beam fundamental transverse mode semiconductor laser chip comprises a chip body, and a first ridge-type waveguide and a second ridge-type waveguide are formed on the upper side of the chip body through one-time etching. Each of the first ridge waveguide and the second ridge waveguide sequentially comprises an active oscillation waveguide area, a passive filtering waveguide area and an active amplification waveguide area in the light emitting direction. The first ridge-type waveguide and the second ridge-type waveguide intersect, and the intersection point is located in the passive filtering waveguide area. And the upper side surfaces of the active oscillation waveguide region and the active amplification waveguide region are provided with P-plane metal connected with the electrodes. An insulating layer is arranged on the upper side face of the chip body, and the P-face metal is exposed outside through an avoiding notch in the insulating layer. The output light spot of the chip is a pure fundamental mode light spot, so that the resolution of the printer can be effectively improved.

This application provides an integrated passive filter circuit, including two first filter units, two second filter units, and a third filter unit. Each filter unit includes a main path and a grounding element connected to the main path. The two second filter units are symmetrical with respect to the third filter unit. The two first filter units are symmetrical with respect to the two second and third filter units. The end of the main path of the first filter unit serves as the port of the integrated passive filter circuit. The third filter unit includes two parallel and different grounding elements. The solution provided in this application employs a semi-symmetrical structure design. The symmetrical structure on both sides effectively improves the consistency at both ends of the filter and simplifies the adjustment of the reflection characteristics on both sides of the device. The asymmetrical structure in the middle improves out-of-band rejection on both sides, reduces the number of devices, and lowers device insertion loss.

The utility model discloses a vehicle control unit high side lamp control broken line detection circuit, a sampling resistor is connected in series on a vehicle control unit high side lamp control driving circuit, and the broken line detection circuit comprises a differential amplification circuit, an active filter, a passive filter and a main detection chip which are connected in sequence; the two ends of the sampling resistor are connected with the two input ends of the differential amplification circuit, the differential amplification circuit amplifies the voltage difference between the two ends of the sampling resistor, and after first-order active filtering and first-order passive filtering are conducted, the voltage is output to an AD analog acquisition port of the main detection chip to be detected and judged. According to the vehicle control unit high-side lamp control broken line detection circuit provided by the utility model, the design of a high-side output broken line detection circuit is added, and whether a corresponding lamp control loop has abnormal conditions such as a broken line fault or overcurrent can be timely and effectively found.

The present application belongs to the field of precision testing technology and instrument, the traditional non-contact current detection meets the basic demand of power monitoring to a certain extent, but when facing the complex and changeable measurement environment and the growing measurement precision requirement, the limitation gradually appears. The present application provides a high-precision large-range current measurement device and signal processing method without switching, through a high-sensitivity signal sampling unit, high-precision sampling of small current analog signals is realized, and two-stage passive filter circuit is added to the signal sampling unit to filter most of the clutter in the analog signal, the digital signal processing method is used in MCU to filter the digital current data with higher precision, the digital signal processing technology is applied to the field of current detection, through optimizing the detection circuit structure and signal processing process, high-precision and high-efficiency current measurement is realized.

The invention discloses an intelligent cooperative harmonic suppression method and related equipment, and the method comprises the steps: obtaining a voltage signal and a current signal, and carrying out the preprocessing, and obtaining the preprocessing data; performing spectrum analysis on the preprocessed data to obtain spectrum data of a plurality of harmonic waves; based on the frequency spectrum data, determining governance weights corresponding to the passive filtering unit, the active filtering unit and the reactor unit respectively; and based on the governance weight, respectively adjusting a capacitance parameter of the passive filter unit, a compensation current parameter of the active filter unit and an impedance parameter of the reactor unit. According to the invention, harmonic wave coverage in a wide frequency range is realized through an intelligent adaptive filtering mode, load fluctuation and power grid frequency deviation are adapted, the harmonic wave treatment effect is more stable, the defects of a traditional harmonic wave treatment technology in coverage range, scene adaptability and volume cost are overcome, and harmonic wave treatment requirements of different scenes can be met.

The invention provides a non-isolated unidirectional Boost converter and a coupling inductor design method thereof, the converter comprises a coupling inductor unit, a primary winding of the coupling inductor unit is used as an excitation inductor of the converter, and a secondary winding of the coupling inductor unit is connected in series with an auxiliary capacitor to form a passive filter branch; wherein the passive filtering branch is connected with an input power supply in parallel; the converter is configured to enable current flowing through the excitation inductor to flow bidirectionally by controlling alternate on-off of the first switch tube and the second switch tube, so that zero-voltage switching-on of the first switch tube or the second switch tube is realized; the passive filtering branch is configured to generate filtering current with the phase opposite to that of a current ripple component of the excitation inductor through the coupling effect of the coupling inductor unit; the filtered current is superimposed with the current ripple component to counteract the ripple of the input current. Zero input current ripples are realized while zero-voltage switching of the switching tube is realized.

An active filter, system, chip and electronic device, comprising: an input end of an RC filter module receives a to-be-filtered signal of the active filter to passively filter the to-be-filtered signal to obtain a passively filtered signal; an output end of a voltage follower module outputs a voltage following the rise and fall of the passively filtered signal to obtain a voltage following signal; a flip voltage follower module makes the filter output end output a voltage following the rise and fall of the voltage following signal to obtain an actively filtered signal; the filter output end is an output end of the active filter; a positive feedback module is connected between the filter output end and the RC filter module, and when the frequency of the to-be-filtered signal falls within a preset cutoff range, the positive feedback module is used to feed back the actively filtered signal to the RC filter module. By setting the flip voltage follower module, the output impedance of the active filter is reduced, so that the active filter can be applied to a high-frequency scene.

The embodiment of the utility model discloses an EMI noise current counteracting circuit and an air conditioning system, and relates to the field of noise reduction circuits. The circuit comprises a current detection module, a passive filtering module, a noise module and a current offset module. The three-phase input end of the current detection module is connected with the three-phase output end of a power grid, the three-phase output end of the current detection module is connected with the three-phase input end of the passive filtering module, the detection end of the current offset module is connected with the detection end of the current detection module, and the current offset module detects the current value of noise current through the current detection module. The offset currents are the same in output current value and opposite to the noise current in direction; the neutral end of the current counteracting module is connected with the neutral end of the power grid, the grounding protection end of the current counteracting module is connected with the grounding protection end of the power grid, and the current counteracting module inputs counteracting current into the EMI noise current counteracting circuit to counteract noise current.

This invention discloses an ultra-high frequency harmonic dynamic control system and method based on adaptive control, belonging to the field of adaptive control technology. The invention acquires ultra-high frequency harmonic signals and divides them into several independent frequency bands, obtaining the occurrence time and duration of each band to form the frequency of harmonic occurrence per unit time. The K-nearest neighbor algorithm is used to analyze this frequency, outputting frequency band classification results and assigning corresponding filtering modes to each band, then executing filtering. The frequency of occurrence per unit time for each band is updated, and the classification status change is compared with the target threshold. The operational stability of passive and active filtering is calculated, and the filtering effect deviation is further calculated. Based on both, a switching command is output. Switching to active filtering disconnects the corresponding passive branch, adjusts the active filtering parameters, and includes it in the control scope. Switching to passive filtering activates the corresponding branch, adjusts the parameters, and removes the frequency band from the active filtering range.

In an aspect, there is provided a hybrid pad set for providing concurrent active and passive filtering in an air filter housing. The hybrid pad set may include a non-pleated active filter media and a pleated passive filter media. The pleated passive filter media may be constructed of a nano-engineered material.