112 results about "Medium frequency" patented technology

The invention relates to the technical field of robot control. A humanoid robot gait generation system based on hierarchical control is characterized by comprising a multi-layer control system operating at different refresh frequencies, and the multi-layer control system comprises a high-layer gait and trajectory planning layer operating at a low frequency and used for generating a macroscopic motion instruction; the middle-layer whole-body motion optimization layer runs at medium frequency, serves as a bridge of high-layer planning and bottom-layer control and is used for converting expected plantar and trunk tracks into reference motion of all joints of the whole body; the bottom joint servo control layer runs at the highest frequency and is responsible for accurately tracking a joint-level instruction output by the whole-body motion optimization layer; the state sensing and feedback closed-loop layer is used for feeding back state information, obtained in real time, of the body state of the robot to all the layers, providing a basis for track re-planning of a high layer and providing a real-time state initial value for optimization of a middle layer; and a feedback signal is provided for servo control of a bottom layer.

The invention relates to the technical field of sound insulation materials, in particular to a high-performance sound insulation material for buildings and a preparation method thereof, and the high-performance sound insulation material comprises the following raw materials in parts by weight: 60-80 parts of polypropylene, 15-25 parts of filler, 10-20 parts of talcum powder, 5-15 parts of flexibilizer, 0.2-1 part of antioxidant and 0.2-0.4 part of light stabilizer. According to the invention, the SEBS with high damping performance is utilized to provide a main viscoelastic effect, and the density performance of the material can be directly increased by combining the barium sulfate material with high density, so that the low and medium frequency sound insulation function is improved, and the hollow glass beads can utilize the spherical surfaces to cause scattering and refraction of sound waves and disturb the propagation direction of the sound waves in the hollow glass beads; meanwhile, in cooperation with the high radius-thickness ratio state of the mica sheet, sound waves are further dispersed and refracted in combination with the hollow glass beads, the conduction path of the sound waves is prolonged, and therefore the medium-high frequency sound insulation performance is improved, and the sound insulation performance of the material is effectively improved.

The invention relates to a fringe projection high-reflection surface phase unwrapping method based on frequency reuse. The fringe projection high-reflection surface phase unwrapping method comprises the steps of collecting a multi-frequency fringe image and dividing the multi-frequency fringe image into an overexposure area and a non-overexposure area, solving a wrapped phase in the non-overexposure area by adopting a generalized phase shift method, obtaining an initial unwrapping phase based on a multi-frequency heterodyne algorithm, and performing block filtering and interpolation processing to obtain a fringe projection high-reflection surface phase unwrapping phase. A continuous unwrapped phase containing a high-reflection area is obtained, a complementary Gray code consistent with a wrapped phase period is constructed in combination with a multi-threshold constraint and is used for correcting the stripe level of an overexposure area, brightness attenuation design is further carried out on low and medium frequency stripes, frequency reuse is achieved, and the high-reflection area is obtained. Obtaining an unwrapped phase of an overexposure point in a non-high-frequency stripe and mapping the unwrapped phase to a high frequency; the method comprises the following steps of: extracting and fusing a wrapped phase by adopting one-dimensional Fourier and Hilbert transform for areas with overexposure of each frequency, and selecting and inhibiting spectrum leakage through a complete period, so that effective correction of the wrapped phase and stripe level of an overexposure point is realized, and a reliable unwrapped phase is obtained.

The invention provides a multimode radio frequency power amplifier module, a radio frequency chip and a mobile terminal. The module comprises two power amplifiers, four switching circuits and a control circuit, an input GSM low-frequency-band radio-frequency signal and a low-frequency-band radio-frequency signal of other communication systems are input into the low-frequency-band power amplifier through the first input switch circuit, and the output of the low-frequency-band power amplifier is connected with one of the low-frequency-band radio-frequency output ports through the first output switch circuit. An input GSM high-frequency-band radio frequency signal and a medium-frequency-band radio frequency signal of other communication systems are input into the medium-frequency-band power amplifier through a second input switch circuit, and the output of the medium-frequency-band power amplifier is connected with one of the medium-frequency-band radio frequency output ports through a second output switch circuit; and the control circuit provides proper working voltage for the low-frequency-band power amplifier and the middle-frequency-band power amplifier respectively. The integration level of the radio frequency amplifier module is improved, the area is reduced, and the cost of the mobile terminal is reduced.

This invention discloses a medium-frequency heating quenching and forming device for steel pipe clamps, belonging to the field of quenching and forming technology. It includes a base plate with a supporting leg installed at the lower corner. A medium-frequency heating coil is installed at the upper end of the base plate. A feeding mechanism is provided on one side of the upper end of the base plate, and a spray quenching mechanism is provided on the other side. The feeding mechanism includes a second cylinder. A connecting block is installed on the side of the base plate, and a second piston rod is installed at the output end of the connecting block. A slider is installed at the other end of the second piston rod. A slide rail corresponding to the slider is opened inside the base plate, and a control component is installed inside the side of the slide rail. A first cylinder is installed at the upper end of the slider. This invention, by setting up a feeding mechanism, combined with an infrared sensor and controller, achieves automatic clamping, precise feeding, and automatic positioning, replacing manual feeding, reducing labor intensity, improving feeding accuracy and heating uniformity, and increasing production efficiency.

The invention discloses a novel non-Newtonian fluid driven fixed abrasive polishing disc, and relates to the technical field of optical element polishing. The fixed abrasive polishing disc comprises an eccentric adjusting frame, a metal back plate, a caliber adjusting ring, a non-Newtonian fluid layer, a rubber sleeve, a fixing ring and a fixed abrasive polishing pad. The metal back plate is matched with the eccentric adjusting frame through the connecting shaft to achieve the adjustable eccentric distance, the caliber adjusting ring can be replaced with different calibers to meet different requirements, the rubber sleeve is filled with the non-Newtonian fluid layer, the fixed abrasive polishing pad is fixed with cerium oxide abrasive, and the size of the fixed abrasive polishing pad is slightly larger than that of the rubber sleeve. The dynamic stiffness characteristic of the non-Newtonian fluid layer is utilized to realize effective correction of full-band errors; the rigidity and efficiency are improved through the fixed grinding material, and hydration reaction is avoided; and multi-structure collaborative optimization of pressure transmission and fringe effect ensures process stability. Experiments show that the fixed abrasive polishing disk can reduce the intermediate frequency error of a fused quartz workpiece to 0.1 mu m and the Ra value to 1.6 nm, is suitable for diversified machining scenes and is high in practicability.

The invention provides an aspheric optical element partition processing path generation method based on an improved Lloyd algorithm, and belongs to the field of aspheric optical element processing.The aspheric optical element partition processing path generation method comprises the steps that firstly, on the basis of surface shape error data of an aspheric optical element, a processing area is divided into a high residual area, a low residual area and a non-processing area through self-adaptive double threshold and adjacent connectivity analysis; and combining the isolated regions. An improved Lloyd algorithm is adopted, high-order iteration and low-order iteration are carried out in a high residual error region and a low residual error region respectively, and a Voronoi grid which is adaptive to the region shape and controllable in density is generated. A spiral path is designed in each Voronoi unit on the basis of the center of mass, and a spiral path based on the Voronoi shape is formed, so that sufficient machining is ensured. According to the method, sudden rotation angles and curvature sudden changes in the path can be effectively avoided, and the processing density can be adaptively adjusted according to the surface shape error, so that the intermediate-frequency error is effectively inhibited, and the surface shape processing quality and efficiency of the aspheric optical element are improved.

The invention relates to a low and medium frequency acoustic measurement and correction method in a high temperature environment, which comprises the following steps of: performing a calibration experiment on an acoustic conduit measurement system under a normal temperature condition to obtain an amplitude correction curve; acoustic measurement is carried out in a high-temperature environment, an inlet end area of a sound conduit is heated to a target high-temperature state through a heating device, a sound source generator is kept to output an excitation signal which is the same as that of a calibration experiment, and sound pressure data of an inlet microphone and sound pressure data of an outlet microphone are synchronously collected; sound pressure data of the inlet microphone and the outlet microphone are converted into frequency domain spectrums through a fast Fourier transform aggregation method, 1 / 3 octave spectrum analysis is carried out, and uncorrected sound pressure levels of all frequency bands are obtained through calculation; and according to the amplitude correction curve, carrying out band-by-band correction on the uncorrected sound pressure level of each frequency band, and synthesizing the corrected sound pressure level of each frequency band into a full-frequency sound level to obtain a corrected high-temperature acoustic measurement result. Compared with the prior art, the accuracy of acoustic measurement of middle and low frequency bands is improved.

The utility model discloses an improved bell gold pendant which comprises an outer shell, a plurality of hollow open grooves are formed in the surface of the outer shell, a bell tongue ball is arranged in the outer shell, an inner cavity shell is arranged in the outer shell, and the bell tongue ball is located between the outer shell and the inner cavity shell. A bell tongue ball is arranged in the inner cavity shell, the bell tongue ball can collide with the inner cavity shell and the outer shell to generate sound when shaking, a plurality of openings are formed in the surface of the inner cavity shell, a solid ball is arranged in the inner cavity shell, and the solid ball can collide with the inner wall of the inner cavity shell to generate sound when shaking. According to the utility model, the bell tongue ball impacts the housing and the inner cavity housing at the same time to generate two independent sound waves, and the sound waves are diffused outwards through the hollowed-out slots to form a high-frequency (housing) and intermediate-frequency (inner cavity housing) superposed sound effect, so that the stereoscopic impression and layering sense of sound are remarkably improved.

The utility model relates to the technical field of sound insulation plasterboards, in particular to a honeycomb sandwich structure of a low-density sound insulation plasterboard, which comprises an upper surface layer, a lower surface layer and a honeycomb core layer, the honeycomb core layer is clamped between the upper surface layer and the lower surface layer and is formed by arranging a plurality of continuous honeycomb units along the plane direction; a resonance dissipation assembly is arranged in each honeycomb unit; the resonance dissipation assembly comprises a closed shell, gradient filling media and an elastic connecting piece, a plurality of through holes are formed in the closed shell, the gradient filling media are arranged in the closed shell in a layered mode, and the elastic connecting piece is elastically connected with the closed shell and the honeycomb unit, so that the resonance dissipation assembly is elastically hung in the honeycomb unit. According to the utility model, the low and medium frequency sound insulation performance can be improved while the light weight is maintained.

The invention belongs to the technical field of satellite communication, and particularly discloses an integrated KaKu dual-frequency transceiver, which comprises an all-in-one machine main body, and is characterized in that the all-in-one machine main body is internally provided with an intermediate frequency selection network used for selecting and separating intermediate frequency signals with different frequencies; the KaKu dual-band BUC module is used for performing up-conversion on the intermediate-frequency signal and amplifying the intermediate-frequency signal into a radio-frequency signal of a Ka or Ku band; the KaKu dual-band LNB module is used for down-converting the radio frequency signal of the Ka or Ku band to an intermediate frequency; and the KaKu dual-band feed network is used for separating and synthesizing the radio frequency signals of the Ka or Ku band which are down-converted to the intermediate frequency. According to the invention, receiving and transmitting duplex of Ka and Ku dual-band signals in one device can be realized, and the problems of single-frequency work, complex device and heavy weight of a traditional terminal can be solved.

The invention discloses a multi-dimensional prediction method and system for periodic weighting of a coal mine working face for edge calculation, which are applied to the field of coal mine down pressure early warning and aim at solving the problems that the false alarm rate of the existing weighting early warning is high, the early warning time delay is relatively high, and sufficient time cannot be provided for speed reduction of a coal mining machine, secondary pressure supplement of a hydraulic support, personnel evacuation and the like. According to the method, whether impact noise exists or not is judged by calculating the standard deviation of collected data, when the impact noise exists, online HP filtering processing is carried out on the collected data, LSTM reasoning is carried out on an intermediate frequency fluctuation item after filtering processing, and early warning is carried out based on a reasoning result and a long-term trend item after filtering processing.

The present application relates to a kind of heat treatment processes for improving H13 mandrel impact energy, comprising the following steps: after forging ultrafine treatment, medium frequency quenching, first tempering, second tempering, after forging heat treatment adopts ultrafine treatment process, eliminates reticular structure, obtains good spheroidizing structure, prepares good organizational condition for subsequent quenching and tempering, performance heat treatment adopts medium frequency quenching and tempering, because medium frequency induction coil heating is carried out by skin effect, heating speed is fast, grain is more fine, product heating and cooling stress is small, product straightness is good, using the heat treatment mode of after forging ultrafine treatment+medium frequency quenching and tempering can make the refining steel diameter≤φ200mm specification mandrel obtain higher strength and good impact energy, better solve the problem of low impact energy of H13 mandrel forgings below specification ≤φ200mm of vacuum refining steel production using conventional heat treatment process, meet product design and use requirement, under the premise of strength satisfying design requirement, room temperature average impact energy KV2≥20J.

The present application relates to the technical field of control system, and especially relates to a vacuum medium frequency furnace operation regulation and control method and system for gas atomization powder production. The method comprises the following steps: acquiring the furnace body inclination angle, the actual residual mass of the metal liquid in the crucible and the actual flow rate of the crucible in the gas atomization pouring process of the vacuum medium frequency furnace in real time; determining the crucible erosion index at the current time; determining the fluid sensitivity factor at the current time; determining the dynamic scaling coefficient for adjusting the fuzzy PID controller output gain at the current time; and performing the operation regulation and control of the vacuum medium frequency furnace based on the improved fuzzy PID controller. By constructing the crucible erosion index and the fluid sensitivity factor, the present application dynamically optimizes the fuzzy PID control gain, matches the crucible state change in real time, solves the problem of poor adaptability of the fixed rule, improves the regulation and control precision and stability of the vacuum medium frequency furnace, and ensures the stable operation of the gas atomization powder production process.

The invention discloses a method for obtaining the thickness and refractive index of a film, a test system, a storage medium and application. The method for obtaining the thickness and the refractive index of the thin film comprises the following steps: obtaining an intermediate frequency signal carrying transmission phase information by using two groups of nonlinear transmission line terahertz frequency comb generators and a broadband mixer, and obtaining an actually measured phase curve based on the intermediate frequency signal; constructing an equivalent multi-optical-path interference model of the thin film, performing coherent superposition on multiple reflection components of a measured wave signal in the thin film in a complex field to obtain a complex phase of a total transmission field, and obtaining a phase-frequency change spectrum based on the complex phase as a model phase curve; and an error function of the model phase curve and the actually measured phase curve is constructed, and a parameter combination enabling the error function to take the minimum value is solved by scanning the parameter combination of the refractive index n and the thickness d of the thin film. According to the method, thermal drift or time drift of the phase is avoided, and then calculation errors caused by phase jump are avoided.

The invention discloses a parallel lithium ion battery fault diagnosis method based on complete ensemble empirical mode decomposition and a time sequence convolutional network. The method comprises the following steps: step 1, acquiring a voltage signal; 2, decomposing the voltage signal by adopting a complete set empirical mode decomposition algorithm to obtain a plurality of intrinsic mode functions and residual errors; 3, based on the information entropy change of each intrinsic mode function component, selecting the intrinsic mode function component with relatively significant entropy change in a low frequency or an intermediate frequency, and reconstructing the original signal to obtain a reconstructed fault signal; 4, inputting the reconstructed fault signal into a time convolution network fused with an attention mechanism for training and diagnosis, and carrying out feature extraction and prediction on the signal; and step 5, fault types are diagnosed and distinguished. According to the invention, rapid and accurate fault detection can be realized under the condition of small voltage change, and the fault diagnosis accuracy is improved.

1. Name of the product in this design: Medium Frequency Modulation Therapy Device. 2. Application of this design: It has the functions of electrotherapy, thermotherapy, and phototherapy. 3. The key design feature of this product is its shape. 4. The image or photograph that best illustrates the design's key points: 3D view 1.

The present application provides a kind of quantitative evaluation method of the influence of wind tunnel inner surface roughness on airflow quality, belongs to the technical field of wind tunnel, the present application is collected by laser confocal scanner wall roughness multi-resolution point cloud data, high frequency, medium frequency and low frequency roughness component is extracted by wavelet decomposition, power spectral density function and fractal dimension are calculated to establish random roughness field probability distribution model, local velocity field and vorticity distribution are obtained by using lattice Boltzmann algorithm to simulate rough wall near flow field, the uniformity of airflow is calculated by generating equivalent random roughness field sample using Monte Carlo method for statistical analysis, the polynomial mapping function of roughness statistical characteristic parameter and airflow quality degradation index is established, when degradation index exceeds allowable threshold, wall roughness is over standard, solve the technical problems of low precision and insufficient calculation efficiency in quantitative evaluation of the influence of multi-scale random roughness on wind tunnel airflow quality.

The present application relates to a kind of seismic waveform classification calculation methods based on multi-frequency data body, belong to the high-quality reservoir prediction technical field of energy exploration field such as oil and gas field exploration, shale gas exploration, geothermal exploration, the method is first based on the 3D seismic data of target interval in study area, using time-frequency analysis method calculates 3 common frequency data bodies such as low frequency, medium frequency, high frequency, then sequentially carries out waveform clustering analysis method based on neural network training for 3 common frequency data bodies and carries out the binary analysis of seismic waveform, the study area is divided into 8 sub-regions, then using original data body carries out waveform overall correlation analysis and merging of 8 sub-regions, finally using different color scale represents the value of sub-region, drawing, using image representation waveform classification result.

1. The name of the design product: interference electric therapeutic instrument. 2. The use of the design product: for two or three ways of medium frequency sine alternating current cross input to human body by outputting low and medium frequency current. 3. The design points of the design product: in shape. 4. The picture or photo that can best show the design points: perspective view.

The invention relates to the technical field of solid waste pyrolysis, in particular to an organic solid waste pyrolysis system based on electromagnetic medium-frequency heating, which comprises an intelligent control unit, a feeding unit, a vibration screening unit, a gradient magnetic suction unit, an eddy current separation unit and a pyrolysis unit, when the humidity sensor signal indicates that the real-time humidity exceeds a preset humidity threshold value, the vibration frequency of the vibration screening unit is improved, the micro-amplitude vibration amplitude of the gradient magnet set is increased, and the space arrangement angle of the gradient magnet set and the screen inclination angle of the vibration screening unit are reduced; and when a signal of the metal content sensor indicates that the real-time metal content exceeds a preset content threshold value, firstly, the space arrangement angle of the gradient magnet group is reduced, the vibration frequency of the vibration screening unit is improved, and then the eddy current frequency of the eddy current sorting unit and the inclination angle of the sorting groove are increased. The separation precision, the processing efficiency and the system stability can be remarkably improved.

The application discloses a vibrating sound production device and electronic equipment. The vibrating sound production device comprises a shell, a sound production unit and a vibrating unit. The sound production unit comprises a magnetic circuit system and a vibrating system matched with the magnetic circuit system. The magnetic circuit system is hollowly arranged to define a mounting hole. The vibrating system comprises a vibrating diaphragm assembly and a voice coil. The vibrating diaphragm assembly surrounds the outer periphery of the vibrating unit. The vibrating diaphragm assembly comprises a vibrating plate, a first folded ring and a second folded ring. One end of the voice coil is connected with the vibrating plate. The other end of the voice coil is inserted into a magnetic gap of the magnetic circuit system. The first folded ring extends along a horizontal direction and is arranged on the side of the vibrating plate away from the vibrating unit. The second folded ring extends along a vertical direction and is arranged on the side of the vibrating plate close to the vibrating unit. One end of the second folded ring is connected with the vibrating plate. According to the vibrating sound production device, the second folded ring is arranged along the vertical direction, thereby prolonging the arrangement length of the vibrating plate, increasing the radiation area of the vibrating plate and improving the medium frequency sensitivity of the sound production unit.

The invention provides an IFA-based spurious coupling multi-band antenna and communication equipment. The IFA-based spurious coupling multi-band antenna comprises a base material and an antenna structure, the base material is provided with a feeding point, an antenna foot and a parasitic foot. The antenna structure comprises a connecting arm, a first radiation arm, a second radiation arm and a third radiation arm, wherein the connecting arm, the first radiation arm, the second radiation arm and the third radiation arm are all arranged on a base material; the connecting arm comprises a first connecting part and a second connecting part which are connected with each other. Compared with the prior art, the IFA-based parasitic coupling multi-frequency-band antenna has the advantages that through the multiple radiation arms and the two gaps, the antenna generates multiple resonances, the working frequency band is widened, the antenna efficiency is better, the low-frequency, intermediate-frequency and high-frequency working frequency bands can be covered, and multi-frequency-band full coverage is achieved; under the condition of not increasing the occupied internal space of the communication equipment, the working frequency band is wider, the space occupied by the antenna is very small, and the cost is reduced.

The invention relates to the technical field of control systems, in particular to a vacuum intermediate frequency furnace operation regulation and control method and system for gas atomization powder preparation. The method comprises the steps that the furnace body inclination angle of the vacuum intermediate frequency furnace in the gas atomization pouring process, the actual residual mass of molten metal in a crucible and the actual flow rate of the crucible are obtained in real time; determining a crucible erosion index at the current moment; determining a fluid sensitivity factor at the current moment; determining a dynamic scaling coefficient used for adjusting the output gain of the fuzzy PID controller at the current moment; and performing operation regulation and control on the vacuum intermediate frequency furnace based on the improved fuzzy PID controller. By constructing the crucible erosion index and the fluid sensitivity factor, dynamically optimizing the fuzzy PID control gain and matching the crucible state change in real time, the problem of poor adaptability of a fixed rule is solved, the regulation and control precision and stability of the vacuum intermediate frequency furnace are improved, and stable operation of the gas atomization powder preparation process is guaranteed.

The present application relates to the technical field of induction heating, in particular to an electromagnetic induction brazing process and device for manufacturing a spiral-welded pipe by using a layered composite metal strip, the electromagnetic induction brazing process and device for manufacturing a spiral-welded pipe by using a layered composite metal strip is a welding method using ultra-high frequency or high frequency, medium frequency induction current as a heat source, high frequency heating is suitable for welding thin-walled pipe fittings, the medium frequency induction brazing equipment can replace the backward preheating means such as oxyacetylene heating, coal oven heating, box-type electric furnace heating and resistance heating, and can be used as a preheating equipment before brazing, the cooperation of the two can greatly improve the product quality, effectively save more than 60% of electric energy, and improve the labor conditions.

The invention relates to the technical field of mine pressure early warning, and discloses an AI algorithm-based mine pressure intelligent monitoring and early warning system and a dynamic analysis method thereof, and the AI algorithm-based mine pressure intelligent monitoring and early warning system comprises a distance sensitive spectrum information extraction module which obtains distance sensitive spectrum information; the radial sequence determining module is used for determining a radial sequence; the radial graph generation module is used for generating a radial graph; the node-level risk quantity calculation module is used for generating node-level risk quantity; the alarm triggering state determining module is used for determining an alarm triggering state; and the spatial positioning module identifies the maximum value position of the continuous risk field as a spatial positioning result. According to the method, distance sensitive spectrum information is extracted, medium frequency dispersion characteristics are fused, association rules of signals and propagation distances are captured, an ordered radial graph is constructed in combination with an energy centroid and a radial sequence, and the internal relation between spatial distribution and spectrum characteristics among nodes is mined through a neural network, so that false alarm and missing alarm conditions are reduced, and the reliability of the system is improved. And the safety production guarantee capability is improved.

The invention provides a power amplifier pin compatible circuit and a radio frequency front-end device, and belongs to the technical field of radio frequency communication. Wherein the universal pin compatible module comprises a plurality of radio-frequency signal lines, each radio-frequency signal line is reserved with a surface mounting position, a first input end of the universal pin compatible module is connected with a high-frequency-band radio-frequency signal, and a second input end of the universal pin compatible module is connected with a middle-frequency-band radio-frequency signal; a first output end of the universal pin compatible module is connected with a seventh pin of the power amplifier, and a second output end of the universal pin compatible module is connected with an eighth pin of the power amplifier; and when the power amplifier is the power amplifier of the target type, the universal pin is compatible with a zero-resistance conduction component on each chip position of each radio frequency signal line corresponding to the target type in the module, so that at least one radio frequency signal line is conducted. According to the invention, the development cost and the maintenance cost of the radio frequency front-end device can be reduced, and the flexibility of the radio frequency front-end device can be improved.

The utility model discloses a silent generator set with a multi-stage noise reduction mechanism. The silent generator set comprises an outer shell, a power unit, a multi-stage noise reduction assembly and an installation frame. The outer shell adopts a double-layer structure and an elastic connecting piece to reduce vibration transmission, and the power unit is installed through a damping cushion block and a sliding rail and is convenient to maintain. The multi-stage noise reduction assembly comprises a first-stage silencer, a second-stage resonant cavity and a third-stage sound absorption plate which are used for controlling high-frequency noise, intermediate-frequency noise and low-frequency noise respectively. The air inlet flow guide cover and the air outlet axial flow fan optimize the airflow path, and airflow noise is reduced. The supporting legs are adjustable and are provided with anti-skid rubber pads, so that the stability is improved. Through multi-stage noise reduction and structure optimization, the noise problem is remarkably improved, the system is suitable for industrial and civil scenes, and quiet and comfortable experience is provided.

This invention provides a comprehensive evaluation method for the mid-frequency performance of a filter field grounding system, belonging to the field of power grid equipment technology. The invention extracts the resonant frequency distribution by inputting a wideband impedance spectrum into an artificial intelligence frequency domain response identification model based on a coarse spatiotemporal attention mechanism. It then dynamically adjusts the spatial receptive field parameters according to the resonant frequency offset function. A three-dimensional electromagnetic field simulation model is established based on soil frequency domain parameters, and the ground potential and current density distribution are calculated using the radial basis function collocation method and the fast multipole algorithm. The entropy value of current distribution uniformity and the Gini coefficient are calculated to identify current concentration areas and assess local overheating risk. Finally, the analytic hierarchy process (AHP) is used to dynamically weight and comprehensively score indicators such as impedance peak value, resonant frequency, ground potential gradient, current uniformity, and overheating risk. This invention solves the technical problem of inaccurate performance evaluation of filter field grounding systems under mid-frequency impulse conditions.

The invention relates to an audio watermark embedding and extracting method for resisting a desynchronization attack, which comprises the following steps of: bearing an embedded bit by using three sections of intermediate-frequency average energy at an embedded end, implementing a triangular modulation strategy on the three sections of average energy according to the embedded bit, and introducing buffer compensation at the embedded end; uniformly scaling all frequency domain coefficients according to a proportion for the buffer expansion interval by taking a segment as a unit, carrying out inverse transformation on the whole frame to obtain frames containing watermarks, and splicing the frames containing the watermarks into audio containing the watermarks; judgment is only carried out on a target frequency band at an extraction side, clipping detection is carried out through symmetric consistency discrimination, rapid and reliable resynchronization in a clipping scene is realized in combination with double-end sliding window search, and blind detection is realized on the premise of not depending on original audio. Compared with the prior art, the method has the advantages that the balance among the watermark capacity, the robustness and the hearing feeling during desynchronization attack resistance is realized, the robustness is improved, and the like.