11results about How to "Wide frequency response range" patented technology

This invention proposes a hysteresis compensation control method for high-speed switching valves based on PWM, belonging to the field of high-speed switching valve control. Its key feature is that the working cycle of the high-speed switching valve is divided into four stages. The rising and falling edges of the reference PWM control the opening and closing times of the high-speed switching valve, while the loading signal consists of on-compensation PWM, excitation PWM, opening-hold PWM, and closing compensation PWM. By varying the pressure before the valve, the critical voltage values ​​for opening and closing the valve core are obtained, thereby controlling the amplitudes of the on-compensation PWM and opening-hold PWM to reduce the hysteresis time and current consumption of the valve core response. The duty cycle of the excitation PWM is determined by the derivative of the pressure before the valve, and the duty cycles of the on-compensation PWM and closing compensation PWM are obtained based on the coil current, accelerating the valve core response speed and optimizing current consumption. This invention can improve the response speed of high-speed switching valves, reduce energy consumption, and expand the frequency response range, offering advantages such as high response, low power consumption, low cost, and small footprint.

The invention provides a superconducting parameter amplifier and a preparation method thereof, and the superconducting parameter amplifier comprises a Josephson junction array which is used for providing resonance nonlinearity; the ground capacitor is used for impedance matching; the linear cavity is used for phase matching; the coupling capacitor is used for coupling the linear cavity and the Josephson junction array; the first end of the Josephson junction array is connected with a signal source and used for receiving a pumping signal and an input signal, the second end of the Josephson junction array is connected with the first end of the ground capacitor and the first end of the coupling capacitor, the second end of the ground capacitor is grounded, the second end of the coupling capacitor is connected with the first end of the linear cavity, and the second end of the linear cavity is grounded. By optimizing the design and preparation process of the superconducting parameter amplifier, the linear cavity and the coupling structure are effectively improved, and the frequency response range of the superconducting parameter amplifier is greatly expanded, so that the quality of microwave quantum optics and superconducting quantum bit measurement signal processing can be effectively improved.

The invention relates to a frequency modulation damper for a double-layer steel chimney, which comprises an inner cylinder, an outer cylinder, a frequency modulation mass block, a spring and a damper, the inner cylinder and the outer cylinder are coaxially arranged, the frequency modulation mass block is arranged between the inner cylinder and the outer cylinder, the spring is connected between the inner cylinder and the frequency modulation mass block, and the damper is connected between the outer cylinder and the frequency modulation mass block. The damper is simple in structure and convenient to install and maintain, the practicability of the damper is improved, meanwhile, the damping parameters of the damper can be adjusted according to the function of the vibration frequency of the steel chimney, and then the stability of the damping effect of the damper is guaranteed.

The invention provides a composite cone as well as a preparation method and application thereof. The composite cone comprises a first surface layer, a second surface layer and a core layer arranged between the two surface layers, the ratio of the total mass of the first surface layer and the second surface layer to the mass of the core layer is 1: (0.5-4); the first surface layer and the second surface layer are prepared from wood pulp and / or bamboo pulp; the bulk of the core layer is greater than 2.0 cm < 3 > / g; the preparation raw materials comprise a second plant fiber, cationic polyacrylamide and an optional non-plant-based filler. Through the design and mutual compounding of the two surface layers and the core layer, the composite cone has the advantages of low density, high rigidity, high modulus, high strength, excellent interlayer binding force and excellent acoustic characteristics. When the composite cone is applied to the loudspeaker, the frequency response range of the loudspeaker can be expanded, the high-frequency segmentation vibration of the loudspeaker is suppressed, and the frequency response curve of the loudspeaker is smoother.

The invention discloses a solid damping material for a passive tension viscous damper and a preparation method of the solid damping material, and relates to the field of damper damping materials, the solid damping material for the passive tension viscous damper comprises the following components by mass: 60-70 parts of a polymer matrix; 8-12 parts of a reinforcing material; 3-5 parts of a plasticizer; 1-2 parts of a cross-linking agent; 5 to 10 parts of a microencapsulated self-repairing agent; and 3-8 parts of modified nano clay. By introducing the reinforcing material and the modified nano clay, the frequency response range of the solid damping material is obviously expanded; by means of the microencapsulated self-repairing agent, the material can be self-repaired when damaged, and historical dependence caused by the memory effect is reduced; the use of the cross-linking agent helps to form a more stable three-dimensional network structure, and the hysteresis effect caused by strain history is reduced.

The application discloses a wake classification and identification method based on a triboelectric sensor, and the method comprises the following steps: collecting a voltage time sequence signal through a fish tail-shaped triboelectric sensor; performing time domain filtering processing on the voltage time sequence signal, presetting corresponding wake category labels and different wake intensity level labels corresponding to the same wake category, and obtaining sample data; performing data segmentation on the sample data to obtain a data sample set; constructing a wake classification and identification model; performing model training on the constructed wake classification and identification model through the data sample set to obtain an optimal wake classification and identification model; and performing wake classification and identification and wake intensity grading according to the optimal wake classification and identification model. The method can effectively capture weak wake signal and suppress background noise, and can identify the nonlinear relationship and multi-scale time dependence hidden in the waveform.

The invention discloses a miniature three-dimensional optical electric field sensing system, comprising a tunable fiber laser, a 1×3 fiber coupler, a three-dimensional electric field probe, a photodetector and an oscilloscope; wherein the tunable fiber laser is connected to the 1×3 fiber coupler through an optical fiber, the 1×3 fiber coupler is connected to the three-dimensional electric field probe through an optical fiber, the three-dimensional electric field probe is connected to the photodetector through an optical fiber, and the photodetector is connected to the oscilloscope through a cable; wherein the three-dimensional electric field probe comprises an x / y / z direction electric field sensor and a shell for packaging; the x / y / z direction electric field sensor comprises a pair of fiber self-focusing lenses and an electric field sensing probe arranged between the two fiber self-focusing lenses, the x / y / z direction electric field sensors have the same posture in the shell, and the electric field sensitive directions of the electric field sensing probe of the x / y / z direction electric field sensor are respectively in the x direction, the y direction and the z direction. The three-dimensional electric field probe of the system has a small volume, is not affected by electromagnetics in measurement, has a wide frequency response range and a large dynamic range.

In a vibration sensor and a microphone provided in this specification, both ends of a vibration beam are fixed on a base, and a middle portion is suspended in a cavity and generates deformation in response to external vibrational excitation. According to the vibration sensor and the microphone, portions, suspended in the cavity, of a plurality of vibration beams have different dimensions by changing a structure and a dimension of the cavity and a dimension and a position of each vibration beam, so that different vibration beams have different natural frequencies, and resonance peaks of different frequencies are generated under vibrational excitation, forming a wider frequency response range. In addition, a vibration signal selected by the vibration sensor and the microphone is a vibration signal within a preset range near the resonance peak, and sensitivity is higher. Moreover, in the vibration sensor and the microphone, a dimension of the cavity of the base is designed to realize multi-resonance peaks and a wide frequency band. The structure is simple, processing difficulty is low, processing costs are low, and a more accurate collection result of the vibration signal may be obtained.

The utility model discloses a compound pendulum type piezoelectric energy recovery device which is compact, practical, higher in environmental adaptability and better in broadband response capability. The single-degree-of-freedom forced vibration device comprises a shell, a base is arranged in the shell, a first piezoelectric plate unit is obliquely installed on the base, a first mass swing block is fixed to the upper end of the first piezoelectric plate unit, when the shell is shaken and vibrated, the first mass swing block shifts, the first piezoelectric plate unit is equivalent to a spring element, and therefore a single-degree-of-freedom forced vibration system is formed; the upper end of the first piezoelectric plate unit is fixed to the lower end of one side of the first mass swing block, the lower end of the other side of the first mass swing block is vertically provided with a second piezoelectric plate unit, the lower end of the second piezoelectric plate unit is fixedly provided with a second mass swing block, the second mass swing block is suspended in the air in the initial state and is perpendicular to the base, and the second mass swing block serves as a second free swing block. Therefore, the compound pendulum type piezoelectric energy recovery device forms a two-degree-of-freedom compound pendulum system. The energy recovery device is applied to the technical field of energy recovery.

The invention discloses a method for testing shielding attenuation and transfer impedance of a high-voltage cable in a vehicle, and the method comprises the steps: preparing equipment, preparing a testing environment, carrying out a transfer impedance test, carrying out a shielding attenuation test, analyzing and recording data, and carrying out the cleaning and arrangement after the test. Therefore, the test process is simpler, more convenient and quicker, current signals under different frequencies can be accurately measured, the shielding attenuation performance of the high-voltage cable under different frequencies can be comprehensively evaluated, the current probe covering various frequency signals has higher sensitivity, weak current signals in the high-voltage cable can be detected, and the shielding attenuation performance of the high-voltage cable under different frequencies can be comprehensively evaluated. Potential problems are found in time, corresponding measures are taken for improvement, the shielding attenuation effect of the high-voltage cable is evaluated more accurately, compatibility with other equipment is good, technicians can observe, analyze and record measurement results conveniently, and the device is suitable for various testing environments.

The invention belongs to the technical field of LED movie screens, and particularly provides a design method of an LED display module PCB, a PCB and an LED movie display screen, according to the method, sound transmission holes of the LED display module PCB are generated in a PCB double-face drilling mode, region matching is conducted on the sound transmission holes and pixel points on the LED display module, and each sound transmission hole of the PCB is in a two-way split horn shape. Through the design of the hole shape and the punching direction of the punched PCB, the overlapping of sound waves is effectively reduced, the return of sound is reduced, and the utilization rate of the sound is improved. And the holes are trumpet-shaped, so that the propagation direction of the sound can be effectively controlled, the sound dispersion is reduced, and the directness of the sound is improved.