78 results about "Band-stop filter" patented technology

The invention belongs to the technical field of image processing, and particularly relates to a cable shielding layer weaving density detection system based on image analysis, which comprises an image correction module, a frequency domain analysis module, a self-adaptive filtering module and a density defect detection module, obtaining the maximum peak point of the centralized complex frequency spectrum; constructing a band elimination filter according to the maximum peak point, filtering the centralized complex frequency spectrum through the band elimination filter to obtain a filtered complex frequency spectrum, executing inverse Fourier transform to obtain a filtered space image, and binarizing the filtered space image through a threshold segmentation algorithm to obtain a pore mask; the porosity is obtained according to the ratio of the non-pore pixel points to the total number of the pixel points; and judging the weaving defect of the shielding layer according to the porosity. According to the method, the strong periodic signals of the weaving textures are automatically identified and filtered in the frequency domain, so that non-periodic defects such as pores are effectively highlighted, the technical problem that periodic textures cover defect signals is solved, and the accuracy of defect detection is improved.

The application belongs to the technical field of image processing, and particularly relates to a cable shielding layer weaving density detection system based on image analysis, which comprises an image correction module, a frequency domain analysis module, an adaptive filtering module and a density defect detection module; a maximum peak point of a centralized complex frequency spectrum is obtained; a band-stop filter is constructed according to the maximum peak point, and the centralized complex frequency spectrum is filtered through the band-stop filter to obtain a filtered complex frequency spectrum and perform inverse Fourier transform to obtain a filtered spatial image, and the filtered spatial image is binarized through a threshold segmentation algorithm to obtain a pore mask; a porosity is obtained according to the ratio of non-pore pixel points to the total number of pixel points; and the shielding layer weaving defect is judged according to the porosity. The application automatically identifies and filters the strong periodicity signal of the weaving texture in the frequency domain, effectively highlights the non-periodic defects such as pores, solves the technical problem that the periodic texture covers the defect signal, and improves the accuracy of defect detection.

The invention discloses a tunable band elimination filter based on a quantum well structure photon time crystal and a method. The tunable band elimination filter comprises the quantum well structure photon time crystal; the quantum well structure photon time crystal comprises a first photon time crystal section, a time domain quantum well section and a second photon time crystal section which are connected in sequence; when an electromagnetic signal is propagated, the electromagnetic signal sequentially passes through the first photon time crystal section, the time domain quantum well section and the second photon time crystal section, so that a stable band gap region and a controllable resonance response are formed in a momentum space; a fitting relation between a local state equivalent wave vector and a time structure parameter is established by adjusting a time section proportion parameter and a refractive index contrast ratio in a quantum well structure photon time crystal, so that the local state quantity and momentum position of an electromagnetic signal are regulated and controlled; and frequency spectrum regulation of the electromagnetic signal is realized through a corresponding relation between the momentum space and the frequency domain space. The frequency spectrum regulation and control precision and the system stability are improved.

The invention provides an elastic wave CT (Computed Tomography) signal denoising method for improving the inversion precision of karst cave exploration, which belongs to the technical field of engineering exploration and comprises the following steps of: performing normalization preprocessing on a received signal, suppressing random noise by adaptive filtering, converting a time domain signal into an F-K domain and identifying a surface wave, filtering a surface wave signal by a Gaussian band elimination filter, and converting the F-K domain signal back to the time domain. The method comprises the following steps of: highlighting a take-off characteristic of a weak P wave covered by a strong surface wave through normalization; using a minimum mean square error adaptive filter to accurately filter random noise; subsequently converting to an F-K domain, and smoothly attenuating the surface wave through a Gaussian band elimination filter by utilizing the frequency wave number distribution difference of the surface wave and the P wave; the method realizes layered removal of random noise and surface waves, finally outputs high-purity direct P-wave signals, greatly improves P-wave travel time pickup and wave velocity calculation precision, and remarkably improves inversion precision of an elastic wave CT exploration method in detection of geologic bodies such as karst caves and fracture zones.

Methods, systems, and devices for wireless communications are described. Generally, the described techniques may enable a user equipment (UE) to disable a sleep mode or awake from sleep earlier for channels or bandwidths that have a frequency spur compared to channels or bandwidths without a frequency spur. Awaking from sleep earlier may enable a band stop filter of the UE to receive more samples to suppress the frequency spur and reduce sensitivity degradation of the UE for decoding control messages. The UE may disable the sleep mode or wake earlier based on a signal-to-noise ratio (SNR) of received signal, a magnitude of the frequency spur, a coding rate of the control message, a bandwidth of the control message, or any combination thereof.

The invention discloses a superconducting microwave resonant cavity, a band elimination filter and a frequency control method, and relates to the technical field of superconducting microwave resonant cavities. The superconducting microwave resonant cavity comprises a thin film layer, a first superconducting electrode, a second superconducting electrode, a third superconducting electrode, a first port and a second port. The first superconducting electrode is arranged on the first surface of the thin film layer; the second superconducting electrode is arranged on one side of the second surface of the thin film layer, a gap exists between the second superconducting electrode and the second surface, and the first end of the second superconducting electrode is connected with the first end of the first superconducting electrode; the third superconducting electrode is arranged on the first surface; the first port is coupled with the first end of the first superconducting electrode and is coupled with the first end of the second superconducting electrode, and the first port receives an external input signal and outputs a target signal; and the second port is connected with the third superconducting electrode and receives an external direct current control signal. The resonant frequency of the microwave resonant cavity is adjustable.

The invention provides an electronic wire harness anti-interference optimization method and system, and the method comprises the steps: S2, blocking a DC component and low-frequency interference through employing a band elimination filter according to the initial spectrum distribution, and extracting a core frequency band of high-frequency signal transmission from a filtered signal; s4, acquiring demand data of voltage grade separation from the signal output, designing an electrical isolation layer through a multi-layer shielding structure, and determining isolation boundaries among different voltage grades; s5, according to the isolation boundary, a space optimization algorithm is adopted to adjust wire harness arrangement in the compact layout, and structural parameters considering isolation and coupling balance are obtained; and S8, according to the final scheme, a time domain reflection method is adopted to detect the distortion rate in signal transmission, the actual effect of improving the anti-interference capability is judged from the detection result, and optimized operation parameters are obtained. The anti-interference capability and the signal transmission quality of the electronic wire harness in a complex electromagnetic environment are effectively improved.

The present disclosure provides a method and device for determining filters in a superconducting quantum chip, and related equipment, relating to the technical field of quantum computing, and particularly to the technical field of superconducting quantum chips. The specific implementation scheme is as follows: determining the center frequencies of two band-stop filters based on the center frequency of a quantum bit of the superconducting quantum chip; determining the lengths of the two band-stop filters based on the center frequencies of the two band-stop filters; and determining the line segment length of a target line segment of a readout line between the two band-stop filters as the distance between the two band-stop filters based on the operating frequency range of the quantum bit; wherein the two band-stop filters are connected to the readout line, and the readout line between the two band-stop filters is coupled to a readout cavity so that the two band-stop filters are distributed on both sides of the readout cavity. In the present disclosure, based on the center frequency of the quantum bit, the key parameters of the band-stop filter can be designed to improve the decoherence time of the quantum bit, and the entire process design is simple and easy to implement.

The application discloses a microwave generation method and device, a microwave generator and a storage medium. The method comprises the following steps: acquiring an optical signal output by an adjustable laser and inputting the optical signal to a preset modulator through a polarization controller; loading a driving signal on the preset modulator and adjusting the power size, and outputting first positive and negative second-order sidebands and second positive and negative second-order sidebands; inputting the first positive and negative second-order sidebands and the second positive and negative second-order sidebands into a polarization maintaining Bragg grating through a circulator, making the sidebands orthogonal to each other through a band-stop filter, and obtaining the first positive and negative second-order sidebands and the second positive and negative second-order sidebands after the orthogonalization; respectively performing modulation processing on the sidebands after the orthogonalization, and obtaining a target signal; and performing spread spectrum on the target signal, and generating a microwave signal. The application acquires two pairs of sidebands through an optical signal and performs modulation, generates a microwave signal after spread spectrum on the target signal obtained, solves the problem of a small adjustable frequency range, and generates an arbitrary waveform phase microwave signal with a large adjustable frequency range and low noise.

The invention relates to the technical field of band elimination filters, and discloses a V-band H-plane rectangular waveguide TE20 mode band elimination filter which comprises a body and a cover plate installed on the body. A main waveguide cavity is arranged on the body, a plurality of TE20 mode rectangular resonant cavities are symmetrically distributed on two sides of the main waveguide cavity, and each TE20 mode rectangular resonant cavity is communicated with the main waveguide cavity through an H-surface capacitance coupling window; a tuning screw is arranged on the cover plate, the tuning screw comprises a threaded part and a light pillar part, the light pillar part extends into the TE20 mode rectangular resonant cavity, and the threaded part is matched and fixed with a threaded hole in the cover plate; the band elimination filter solves the problems that an existing band elimination filter is wide in transition band and large in loss.

The present application relates to the technical field of electric power metering, and especially relates to a kind of electric energy meter state in network monitoring method, device, terminal and storage medium, the electric energy meter state in network monitoring method disclosed by the present application is loaded harmonic through trunk line, harmonic and the waveform of the current of trunk line and branch line line have obvious difference, by opening the band-stop filter in each branch line line, so that the harmonic current of trunk line only passes through the electric energy meter for detection, then by comparing the data of the electric energy meter to be detected with the data of total meter, whether the electric energy meter to be detected meets the precision requirement can be obtained, therefore, after applying the method of the present application, the electric energy meter can be completed online detection without disassembly, equipment resources and human resources are saved, and the reliable operation and measurement accuracy of the electric energy meter are also guaranteed.

A radio frequency front-end circuit includes a first diplexer, an extractor, and a second diplexer. First diplexer is coupled to an antenna for receiving a radio frequency signal and configured to separate radio frequency signal into a first signal within low, mid and high bands of a wireless wide area network and a second signal within an ultra-high band of WWAN. Extractor is coupled to first diplexer. Extractor includes two band pass filters and a band rejection filter. Two band pass filters are configured to extract two global navigation system signals within two global navigation system bands from first signal. Band rejection filter is configured to allow a third signal within the mid and high bands of WWAN in first signal to pass. Second diplexer is coupled to first diplexer and extractor and configured to combine second and third signals into a WWAN signal.

This invention discloses an IPMSM position estimation method and system based on rotating high-frequency injection, comprising: (1) injecting a high-frequency voltage signal into the stationary α-β coordinate axis of the motor; (2) sampling the three-phase current and obtaining the two-phase stationary coordinate system through Clark transformation; (3) obtaining the fundamental current through a notch filter; (4) obtaining the high-frequency response current of the stationary α-β coordinate axis; (5) rotating the transformation and obtaining the high-frequency response negative sequence current through low-pass filtering; (6) designing and modulating the compensation phase; (7) cross-multiplying the compensation phase vector with the modulated compensation phase vector to obtain the estimated angular velocity and rotor position of the motor. This invention uses a notch filter to process the signal, eliminating the band-stop filter in the d-axis and q-axis current feedback loop in the control loop, thus simplifying the system complexity; by compensating for the rotor position lag angle, it increases the system stability and improves the rotor position identification accuracy.

Enhancing spurious rejection in an acoustic filter circuit is provided. Specifically, the filter circuit includes an acoustic bandpass filter circuit and an acoustic bandstop filter circuit. In embodiments disclosed herein, the acoustic bandpass filter circuit and the acoustic bandstop filter circuit can be integrated into either a single semiconductor die or a single system-in-package (SiP). By integrating the acoustic bandstop filter circuit with the acoustic bandpass filter circuit, it is possible to enhance spurious rejection with minimum impact on insertion loss and passband performance to thereby improve overall performance of the acoustic filter circuit. Moreover, it is possible to reduce fabrication variation and cost of the acoustic filter circuit as well.

The invention discloses a large-range coupling adjustable structure of a band elimination filter, and belongs to the field of band elimination filters. A large-range coupling adjustable structure of a band elimination filter comprises a cavity and further comprises an input connector and an output connector which are arranged on the outer walls of the two sides of the cavity respectively. The cover plate is arranged on the cavity, and a plurality of groups of frequency tuning screws are arranged on the cover plate; the plurality of groups of resonant columns are fixedly connected in the cavity, and the plurality of groups of resonant columns are respectively matched with the plurality of groups of frequency tuning screws; the copper sheet is arranged in the cavity, and the two ends of the copper sheet are matched with the input connector and the output connector respectively; the auxiliary tuning screw is arranged on the cover plate, and the bottom of the auxiliary tuning screw penetrates through the cover plate and is arranged in the cavity; according to the invention, the problems of difficult design and debugging, long debugging time span and the like of the band elimination filter in the design, assembly and debugging process are solved, and the characteristics of stability, consistency, reliability, operability, low cost and the like are improved.

A high-frequency tunable bandstop filter based on a YIG substrate belongs to the field of microwave magnetic device technology. It includes a YIG substrate, functional metal layers and ground metal layers formed on the front and back sides of the YIG substrate; the functional metal layers include a microstrip line structure penetrating the YIG substrate, and a square open-loop resonant ring structure disposed on one side of the microstrip line structure. This invention utilizes the tunable permeability of the YIG substrate as a tuning source, overcoming the limitations of traditional fixed resonant structures and methods using semiconductor varactor diodes, ferroelectric materials, or piezoelectric materials, which cannot meet the poor adaptability to high-frequency scenarios and environments. It achieves precise suppression of dynamic electromagnetic interference frequencies at their source; by employing a composite structure of a square open-loop resonant ring and a microstrip line, and YIG substrate-compatible semiconductor wafer technology, it achieves real-time high-frequency signal tuning processing, meeting the current low-cost and high-integration industrial application value.

The invention provides a double-frequency cavity band-stop filter based on a defect ridge waveguide, relates to the technical field of wireless communication, and solves the problems that a waveguide band-stop filter in the prior art is usually formed by loading stub resonators on a main waveguide transmission line at an interval of odd number times of 1 / 4 waveguide wavelength, and although the performance is good, the band-stop filter cannot be used normally. However, the additional resonant cavity causes the technical problems of large structure size and complex processing. According to the technical scheme, through grooves with step widths are etched in a metal ridge in the transmission direction to construct defect ridge waveguide band elimination units, and the double-frequency band elimination filter based on the defect ridge waveguide structure is provided. According to the invention, an extra resonant cavity is avoided, the size of the device is reduced, the passband insertion loss is relatively low, the stopband suppression level is good, and excellent performance is shown.

This invention relates to a method and apparatus for suppressing synchronous oscillations in a power synchronous control converter. The method involves obtaining a first difference ΔP between a reference value of active power and a measured value of active power at the grid connection point of the power synchronous control converter; obtaining a first difference ΔQ between a reference value of reactive power and a measured value of reactive power at the grid connection point of the power synchronous control converter; limiting the synchronous frequency component of the first difference ΔP using a first band-stop filter to obtain a second difference ΔP; obtaining a reference phase of a modulation signal based on the second difference ΔP; limiting the synchronous frequency component of the first difference ΔQ using a second band-stop filter to obtain a second difference ΔQ; calculating a reference voltage amplitude of the modulation signal based on the second difference ΔQ; and generating a modulation signal for controlling the power synchronous control converter based on the reference phase and reference voltage amplitude of the modulation signal. This invention can effectively suppress synchronous oscillations during the operation of a power synchronous control converter.

The invention discloses a self-adaptive predictive control method for a synchronous reluctance motor system with a sine wave filter, and belongs to the field of motor control. The method comprises the following steps: sampling information of a synchronous reluctance motor system with a sine wave filter at a k moment, and establishing a fixed parameter prediction model of the system by adopting a first-order Runge-Kutta discrete method; establishing a self-adaptive prediction model of the system, constructing a self-adaptive parameter estimation function, and solving a self-adaptive parameter estimation law according to a minimum value principle; filtering inductive current least-beat prediction control is carried out on the self-adaptive prediction model, and an obtained self-adaptive prediction control instruction is input into a band elimination filter to realize resonance suppression; and performing synchronous rotation inverse transformation on the self-adaptive prediction control instruction, and then sending the self-adaptive prediction control instruction to a space vector modulation generation pulse to act on an inverter switching tube so as to realize self-adaptive prediction control. Compared with a traditional predictive control method, the method is easy to implement and has high robustness and stability for model parameter mismatch.

The invention discloses a filtering method and system for suppressing high-frequency oscillation of a flexible direct current converter, and the method comprises the steps: arranging a band elimination filter in an inner loop current controller of the flexible direct current converter, and carrying out the filtering of the high-frequency oscillation of the flexible direct current converter when the high-frequency oscillation of the flexible direct current converter and an alternating current power grid connected with the flexible direct current converter is detected; the center frequency of the band elimination filter is adaptively adjusted based on the high-frequency oscillation frequency and the high-frequency oscillation type of the flexible direct-current converter, so that the impedance characteristic of the flexible direct-current converter can be effectively enhanced in a high-frequency band, and high-frequency oscillation suppression of the flexible direct-current converter is realized. And the multi-frequency-point oscillation problem caused by different alternating-current power grid operation modes can be solved.

The invention discloses a microstrip band-stop filter with a wide upper passband, and relates to the technical field of radio frequency passive devices, and the microstrip band-stop filter comprises an electromagnetic shielding cavity, a dielectric substrate, a microstrip circuit located on the front surface of the dielectric substrate, and a grounding metal layer located on the back surface of the dielectric substrate. The microstrip circuit is composed of an input feeder line, an output feeder line and a four-stage cascade filter network located between the input feeder line and the output feeder line. The stopband center frequencies of the four filtering units are distributed in a staggered manner so as to broaden the stopband bandwidth; each filtering unit is composed of two U-shaped micro-strips and an interdigital capacitor, and symmetrical rectangular split ring resonators loaded with the interdigital capacitors and double-path arc-shaped parallel micro-strip lines are adopted at the interstage connecting positions of the filtering units respectively. According to the invention, the low insertion loss, high selectivity and miniaturization design of the filter are realized, and the technical problem that the existing band elimination filter is difficult to adapt to a complex and changeable signal environment due to the limited passband width is solved.

The application relates to the technical field of electric energy metering, in particular to a wide-frequency alternating-current power measuring device and method based on thermoelectric converters, wherein the device comprises a band-pass filter and a band-stop filter, and the fundamental wave voltage, the fundamental wave current, the harmonic wave voltage and the harmonic wave current are obtained based on the measured voltage signal and the measured current signal; the first adder and the second adder and the first subtractor and the second subtractor output the fundamental wave component and the harmonic wave component; the first to fifth thermoelectric converters perform electric-thermal conversion to obtain equivalent direct-current parameters corresponding to the fundamental wave component and the harmonic wave component; and the sampling microcontroller obtains the fundamental wave power, the harmonic wave power and the fundamental wave power factor. According to the application, the measurement of the fundamental wave power and the harmonic wave power can be realized based on the thermoelectric converters under the condition that the voltage and current signals have harmonics, the fundamental wave power factor is obtained, the range width of the frequency response is improved, the cost of the high-frequency power measurement is reduced, and the accuracy and the practicability are higher.

The application provides a direct-drive wind turbine active damping control method suitable for extremely weak power grids, comprising: a first oscillation stability improvement control strategy of a grid-side converter of a direct-drive wind turbine, and a second oscillation stability improvement control strategy of a machine-side converter; the first oscillation stability improvement control strategy is to apply d-axis and q-axis current components to corresponding voltage channels after damping compensation through the combination of a high-pass filter and a virtual impedance link; meanwhile, the q-axis current components are cross-compensated to the d-axis voltage channel after passing through a band-stop filter and a virtual impedance link; the second oscillation stability improvement control strategy is to apply d-axis and q-axis current components to corresponding voltage channels after damping compensation through the combination of a band-stop filter and a virtual impedance link. Through the grid-side converter control strategy and the machine-side converter control strategy, the oscillation stability of the direct-drive wind turbine is improved under the condition of extremely weak power grids, and the dynamic performance is not affected.

The embodiment of the invention provides a quasi-plane band elimination filter based on a wide and narrow side hybrid coupling structure, and relates to the technical field of filters, the quasi-plane band elimination filter comprises a rectangular micro coaxial line, a conductor inner core and a shell, the conductor inner core is arranged in the shell, a gap exists between the conductor inner core and the shell, and the gap is filled with an air medium. The plurality of resonator structures are positioned between the conductor inner core and the shell, are arranged at the top and the side part of the conductor inner core, and are used for loading the rectangular micro coaxial line through electromagnetic coupling; and an opening is formed in a shell area opposite to the resonator structure arranged at the top of the conductor inner core on the shell. And the conductor inner core and the shell of the rectangular micro coaxial line and the plurality of resonator structures are all made of copper. According to the embodiment of the invention, the requirements of miniaturization, light weight and high integration level can be met, and the filtering performance is ensured.

The invention provides an integrated multi-frequency adjustable band elimination filter. The integrated multi-frequency adjustable band elimination filter comprises more than one adjustable band elimination filtering module, each adjustable band elimination filtering module comprises a 90-degree bridge and a frequency hopping combiner; the 90-degree bridge is provided with an input end IN, an isolation end ISO and two coupling ends; the frequency hopping combiner is connected between two coupling ends of the 90-degree bridge; the frequency hopping combiner comprises a combining matching unit and N frequency hopping band-pass filters which are connected in parallel through the combining matching unit, and N is an integer greater than or equal to 2; and the combining matching unit is configured to enable the N frequency hopping band-pass filters which are connected in parallel to have no influence on impedance at a common combining point, so that N independent adjustable band elimination frequencies are realized. The multi-frequency adjustable band elimination filter adopts a parallel structure, and a plurality of frequency hopping band-pass filters are connected in parallel on a shared 90-degree bridge through a frequency hopping combiner, so that multi-frequency band elimination is realized.

The utility model belongs to the technical field of partial discharge insulation detection, and particularly discloses a novel anti-interference ultrahigh frequency partial discharge detection circuit, which comprises an antenna, a balun circuit and a band elimination filter, the antenna is used for receiving ultrahigh-frequency electromagnetic wave signals generated by partial discharge, the output end of the antenna is connected with the balun circuit, the output end of the balun circuit is connected with the band elimination filter, and the output end of the band elimination filter is integrated with an SMA connector and used for outputting the ultrahigh-frequency electromagnetic wave signals. According to the utility model, the Balun, the band elimination filter and the antenna are placed together, so that partial discharge signals can be effectively received and processed, external interference signals are suppressed, and accurate detection of partial discharge of electrical equipment is realized.

The present application relates to the technical field of aero-engine control, and discloses a disturbance-resistant steady-state rotating speed control system for a micro turbojet engine based on a sliding mode variable structure, which comprises: a parameter solving unit that calculates a notch frequency based on the phase-reversed superposition relationship between a combustion branch and a bearing lubrication branch; a pre-filtering unit that processes a rotating speed deviation signal by using a band-stop filter with a center frequency of the notch frequency to generate an avoidance deviation signal; a sliding mode controller that determines a gain adjustment coefficient based on the amplitude attenuation ratio at the notch frequency, and generates a primary fuel instruction by using a continuous second-order hyper-spiral algorithm; and a post-filtering unit that performs notch filtering on the primary fuel instruction again to generate a final fuel instruction. The present application can effectively avoid the gain collapse frequency band caused by fuel shunting configuration, prevent the misinjection of control energy into a non-rotating speed channel, and improve the steady-state control precision and operation reliability of the engine.

The present specification relates to the field of signal measurement, and discloses a test method and system for high-power transmitter products to solve the problem of insufficient accuracy of harmonic and spurious amplitude measurement results of high-power transmitters in the prior art. The present application comprises: sequentially connecting the to-be-tested transmitter, the high-power attenuator and the EMI receiver through a cable; making the to-be-tested transmitter output a preset working signal; adjusting the scanning parameters of the EMI receiver to obtain the maximum indication value of the fundamental power level; replacing the high-power attenuator with a band-stop filter suitable for the frequency band to suppress the fundamental amplitude and obtain the transmission signal; scanning to obtain the antenna port harmonic and spurious conducted emission level; and comparing the preset test standard to obtain the test result. The present application improves the test method, effectively improves the measurement and evaluation of the antenna port harmonic and spurious conducted emission level of the key transmitter product, and improves the accuracy and operability of the laboratory in the antenna port conducted emission test process.

An antenna module includes a radiating element having a planar shape, a ground electrode arranged so as to face the radiating element), first and second power feeding lines, and first and second band-stop filters. The first power feeding line is configured to transmit a radio frequency signal in a first frequency band to a first feed point of the radiating element. The second power feeding line is configured to transmit a radio frequency signal in a second frequency band higher than the first frequency band to a second feed point of the radiating element. The first filter is connected to the power feeding line and configured to inhibit passage of a radio frequency signal in the second frequency band. The second filter is connected to the second power feeding line and is configured to inhibit passage of a radio frequency signal in the first frequency band.