Patents
Literature
Patsnap Copilot is an intelligent assistant for R&D personnel, combined with Patent DNA, to facilitate innovative research.
Patsnap Copilot

163 results about "Periodic wave" patented technology

A periodic wave generally follows a sine wave pattern, as shown in the diagram. A number of parameters can be defined to describe a periodic wave: frequency (f = 1/T) - number of cycles in a certain time, usually in 1 second.

Method for capturing object by using last pulse policy of laser seeker of unmanned aerial vehicle

ActiveCN103983145AAccurate captureOvercoming the disadvantages of laser guidanceSelf-propelled projectilesSemi activeSevere weather
The invention discloses a method for capturing an object by using a last pulse policy of a laser seeker of an unmanned aerial vehicle. According to the method disclosed by the invention, the last pulse policy is adopted, by means of effectively identifying a last pulse of an echo in a single laser period and filtering out atmosphere back scattering echo pulses, an echo signal of the object can be accurately captured within a signal gating time of a seeker detector, so that a laser semi-active seeker of an airborne guided missile of the unmanned aerial vehicle can filter out atmosphere back scattering echo signals and repeater inductive signals, can identify a real object echo pulse signal, in this way, disadvantages of laser guidance can be overcome, capturing, tracking and locking precisions for the object are greatly improved; according to the method disclosed by the invention, the last pulse policy is adopted, two sampling holders are used to perform alternative sampling and to keep gating, pulses in gates of a single laser periodic wave are all sampled, back scattering pulses or induced signal pulses which arrive before an object echo are filtered out, and the last pulse, namely the object pulse, is preserved, in this way, a signal-to-noise ratio of the object echo signal is greatly increased, and a striking effect of the airborne guided missile of the unmanned aerial vehicle under severe weather conditions is improved.
Owner:CHINA ACAD OF AEROSPACE AERODYNAMICS

Dual-frequency wideband wave absorber

The invention discloses a dual-frequency wideband wave absorber, which comprises a periodic wave absorption surface structure, a first layer medium base plate, a periodic frequency selection surface structure, a second layer medium base plate, a metal shielding floor and plastic screws used for connecting the first layer medium base plate and the second layer medium base plate, wherein the periodic wave absorption surface structure is printed on the first layer medium base plate and consists of two metal round sheets, two opening resonant rings and wave absorption structure units; the two metal round sheets are symmetrical at the left side and the right side; the two opening resonant rings are symmetrical at the left side and the right side; the wave absorption structure unit is welded between the two metal round sheet arms. The periodic frequency selection surface structure is formed by a plurality of metal resonant units printed on the second layer medium base plate. The metal shielding floor is printed on the back side of the second layer medium base plate. The opening resonant rings and the metal resonant units simultaneously act to realize the reflection characteristics in a certain frequency band range, so that the double-frequency wideband sound absorption is formed. The wave absorption band width and the wave absorption rate can be changed through regulating the distance between the first layer medium base plate and the second layer medium base plate.
Owner:UNIV OF ELECTRONIC SCI & TECH OF CHINA

Coding wave-absorbing meta-material for reflection section reduction of broadband radar

The invention relates to a coding wave-absorbing meta-material for the reflection section reduction of a broadband radar, and relates to the technical field of radar hiding and novel artificial electromagnetic materials. The meta-material comprises a plurality of periodic unit structures, and each unit structure comprises an upper conductive film layer, a dielectric substrate and a metal reflection backboard, wherein the upper conductive film layer is located on the upper surface of the dielectric substrate. The plurality of unit structures are arranged to be symmetric, thereby guaranteeing that an electromagnetic wave represents polarization insensitive characteristics. The wave-absorbing meta-material is spatially arranged, and has the symmetry breaking characteristics, wherein the arrangement mode is determined by the characteristics of the coding wave-absorbing meta-material. The wave-absorbing meta-material can achieve the RCS reduction effect (10dB or more) in a range of 6.5-20 GHz. Particularly, the target RCS reduction effect is better than the RCS reduction effect of pure periodic wave-absorbing materials in the range of 9-20GHz. The coding wave-absorbing meta-material isbetter in target RCS reduction than a conventional coding meta-material and the wave-absorbing materials. Moreover, the meta-material is simple in technology, integrates the structure with the functions, is small in areal density, and can play an important role in the field of target hiding.
Owner:AIR FORCE UNIV PLA

Control method and device of inverter and inverter system

The embodiment of the invention provides a control method and device of an inverter and an inverter system. The control method and device of the inverter and the inverter system solve the problems that in a photovoltaic grid-connected electricity generation system, in order to improve the utilization rate of direct current at the two ends of a solar panel for the inverter, common mode components are usually injected into modulating waves of the inverter for three times, and therefore the conversion efficiency of the inverter is low. The control method of the inverter comprises the steps that the voltage of the direct current currently output by a solar panel array connected with the inverter is determined, when the voltage of the direct current is larger than or equal to the current preset voltage, the modulating waves are output to the inverter, the modulating waves only contain periodic waves with a preset frequency, and the modulating waves are used for controlling the inverter to convert the direct current output by the solar panel array into alternating current, and when the inverter converts the direct current with the voltage larger than or equal to the current preset direct current into the alternating current under the control of the modulating waves, the distortion of the alternating current is located in a range currently permitted by a power grid where the inverter is connected into.
Owner:HUAWEI DIGITAL POWER TECH CO LTD

Self Cleaning Aquarium System

An aquarium system for containing water and aquatic life therein is disclosed that includes a reservoir and an aquarium that is mounted generally above the reservoir. The aquarium has an outlet in liquid communication with the reservoir through an outlet conduit that includes a discharge means, preferably an inverted U-shaped siphon conduit, that periodically discharges a portion of the water from the aquarium to the reservoir therethrough once the water has reached a maximum water level. A pumping means pumps water from the reservoir up to the aquarium through an inlet conduit that is in fluid communication with the reservoir and an inlet of the aquarium. As such, when the water reaches the maximum level in the aquarium, the siphon conduit substantially fills with water which begins to flow out through the outlet conduit, drawing a portion of water from the aquarium rapidly through the outlet conduit until the water in the aquarium reaches the open bottom end of the siphon conduit. Air in the aquarium thereafter enters the siphon conduit to break the siphon. Water leaving the output conduit enters a filter means to filter and clean the water before it is returned to the aquarium by the pump. An embodiment emulating the current of a river, wherein the aquarium takes the shape of an elongated, substantially transparent tube or trough, is further disclosed. A wave surge means may be included for producing periodic wave surges in the aquarium.
Owner:GRAD ANDREW
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products