51results about How to "Self noise reduction" patented technology

A partial optical fiber discharge detecting system comprises a light source, an acoustic-optic modulation device, a sensing light path and a demodulating system. Frequency shifting and delaying are carried out on light emitted by the light source through the acoustic-optic modulation device, and only two paths of light with the same optical path can interfere in the sensing light path and a reference light path. When partial discharge signals occur outside, the generated sound waves act on the sensing light path, the phase position of the interference signals changes, and the related information (intensity, position and the like) of outside partial discharge signals can be obtained by demodulating the variable quantity. Compared with traditional electromagnetic sensing and piezoelectric sensing, optical fiber sensing is insulated from electromagnetism essentially, the sensing optical fiber can be arranged in insulating oil of a transformer, the sensitivity for detecting the partial discharge signals is further improved, multiplexing can be formed easily, and the partial discharge signals can be precisely positioned.

The invention provides a water surface rainfall intensity measurement method based on rain sound spectrum and a device thereof, relates to water surface rainfall intensity measurement, and specifically provides a water surface rainfall intensity measurement device which is based on a DSP digital acquisition system and has the advantages of high anti-interference, low self noise, high reliability, high bandwidth and data mass memory as well as a method. The device is provided with a gas-tight silo, a gas-tight silo float, a hydrophone, a hydrophone float and a circuit. In the measurement method, frequency range division and shape of underwater rain sound spectrum are adopted in combination with the least square method and the non-linear method to invert water surface rainfall intensity; according to log-linear change principle of the sound spectrum at the frequency range ranging from 15kHz to 30kHz, rainfall is divided into 3 types: no rain, light rain and heavy rain; an S-type growth model is adopted to study the sound spectrum principle in the process of the light rain and quantize rainfall intensity in the process of light rainfall; a log-linear model is adopted to study the sound spectrum principle in the process of heavy rainfall and the low frequency range of 2-10KHz of the rain sound spectrum and parameter value of the log-log model are adopted to quantize the rainfall intensity in the process of the heavy rainfall.

The invention discloses an oceanic capacitive electrode and is applied to ocean electric field measurement in the field of geophysical exploration. The oceanic capacitive electrode mainly comprises a capacitive electrode body made of metal materials and a protecting structure, and an insulating layer is arranged on the surface of the capacitive electrode body and is high in insulating property and corrosion resistance. The oceanic capacitive electrode has the advantages that direct contact between the capacitive electrode body and external environment media is avoided by the insulating layer, the electrode body and external electrolyte form a capacitor, and an external electric field is measured by means of capacitive coupling; in the presence of the insulating layer, chemical reaction between the electrode and ions in seawater is avoided, electrochemical noise generated during the chemical reaction is further avoided, and the electrode can achieve lower noise level; meanwhile, stabilization time for the electrode to establish balance is shortened, and continuous consumption during electrode use is avoided.

The invention provides a low-noise vector hydrophone. The low-noise vector hydrophone comprises an underwater sensitive probe (1), a lead wire (3), a sealing housing (4), an installation pedestal (6), a conditioning chamber (7), a conditioning circuit (8) and a cable (9), wherein the underwater sensitive probe (1) is connected with the sealing housing (4) through an internal vibration damping structure (2), a first sealing ring (5) is arranged between the sealing housing (4) and the installation pedestal (6), the conditioning circuit (8) is installed in the conditioning chamber (7), a second sealing ring is arranged between the conditioning chamber (7) and the installation pedestal (6), and signals subjected to amplification filtering conditioning through the conditioning circuit are transmitted via the cable (9). According to the invention, self-noise from the inside of the vector hydrophone is effectively reduced, the capability of resisting interference from external vibration and electricity, electromagnetism and sound is improved, the equivalent self-noise acceleration spectrum level is of the low-noise vector hydrophone is enabled to reach lowest level, and the pick-up demand of underwater sound field weak signals can be satisfied.

The invention relates to an anechoic tile based on a composite material, in particular to an anechoic tile made of a foam metal material and a rare-earth supermagnetostrictive material, and belongs to the technical field of anechoic. It is composed of foamed metal material sheet with certain radian and thickness, rare earth super magnetostrictive material sheet, and synthetic rubber sheet which is vulcanized and packaged into an integral structure after they are bonded to each other. The shapes of the metal foam material sheet and the rare earth super magnetostrictive material sheet are consistent, and their radians are consistent with the surface radian of the underwater moving body. After being encapsulated by a synthetic rubber sheet, they jointly form an anechoic tile. The invention can not only absorb the sound waves of the active sonar, significantly reduce the reflection intensity of the sound waves of the active sonar, but also suppress the vibration generated by the underwater moving body itself, isolate the machine noise in the underwater moving body from radiating to the underwater moving body, and significantly reduce the Self-noise of underwater moving bodies, reducing the passive sonar range of the detection side, etc.

The invention discloses a real-time processing system of modularized array acoustic signals, and belongs to the technical field of ocean acoustic signal collection. The system comprises a mounting base, and data collection modules, a signal processing module, a storage module, a clock module, a control module and a power supply module mounted on the mounting base; the data collection modules receive analog electric signals output by an acoustic sensor, and process the analog electric signals; the signal processing module makes data interaction with the data collection module, and carries out time-frequency conversion, weak signal detection and target signal identification on data; the control module is used for synchronous management of the data collection modules and communication among the modules; the power supply module supplies power for the modules; and the data collection module, the signal processing module, the storage module, the clock module, the control module and the powersupply module are integrated on PCBs respectively, and each PCB is provided with the same data input and output ports. Thus, the signal to noise ratio as well as the collection consistency of an underwater acoustic signal collection array circuit can be improved.

The invention discloses a wide-band high-sensitivity planar optical fiber vector hydrophone. The wide-band high-sensitivity planar optical fiber vector hydrophone mainly comprises optical fiber acceleration sensing units; four optical fiber acceleration sensing units are connected in series so as to form the hydrophone; a 2*2 coupler and Faraday rotation mirrors are fixed in an interferometer box; the acceleration sensing units and the interferometer box are fixed on a polyurethane foam board; fixing screws are distributed at four corners of the polyurethane foam board; the input and output optical fibers of the hydrophone are led out by an optical cable; the outermost layer of the hydrophone is sealed through filling a polyurethane adhesive layer; the optical fiber acceleration sensing unit is mainly composed of optical fiber discs, a sensitizing structure and shells, wherein two optical fiber discs are bonded at the upper surface and lower surface of the sensitizing structure, and the sensitizing structure is bonded to the upper shell and the lower shell through an epoxy adhesive. As for the requirements of work bandwidth and high sensitivity of a conformal array hydrophone, the acceleration sensing units are adopted, and the optical path and structure of the hydrophone of the invention are optimized, and therefore, technical problems in corresponding process implementation and assembly can be solved.

The invention discloses a low self-noise stainless steel wire. The diameter of the low self-noise stainless steel wire is 5.9-6.1 mm. The low self-noise stainless steel wire comprises, by mass percentage, 0.01-0.03% of carbon, 13-17% of chromium, 4-8% of nickel, 0.1-0.12 % of copper, 0.4-0.5 % of magnesium, 1-1.2% of manganese, and the balance iron. The prepared low self-noise stainless steel wire greatly improves the abrasion resistance and corrosion resistance performance, is easy to machine and form, has certain vibration reducing performance, is low in self-noise, better solves the problems that steel wires are likely to be corroded, rusted and abraded and large in noise, and prolongs the service life.

The invention relates to a sound eliminating tile made of a piezoelectric material. An arc-shaped piezoelectric material block is vulcanized and encapsulated into novel synthetic rubber and used for underwater moving body shell surface and bridge surface. According to the basic principle that the density of piezoelectric material surface charge is in proportion to applied stress, an active sound eliminating tile for a hollow cavity type or a filler type underwater moving body shell surface is designed. By using the piezoelectric material as a core, the invention reduces the reflecting strength of a sound wave of an active sonar, inhibits vibration generated by an underwater moving body, isolates machine noise in the underwater moving body from being radiated to an underwater moving body and can obviously reduce the reflecting strength of the sound wave of the active sonar and the radiating noise and self noise of the underwater moving body and provide basis for the design of hidden and silent type underwater moving bodies.

The invention discloses a preparation method for a low-self-noise stainless steel wire. The diameter of the low-self-noise stainless steel wire is 5.9-6.1 mm. The low-self-noise stainless steel wire comprises, by mass, 0.01%-0.03% of carbon, 13%-17% of chrome, 4%-8% of nickel, 0.1%-0.12% of copper, 0.4%-0.5% of magnesium, 1%-1.2% of manganese and the balance iron. According to the low-self-noise stainless steel wire prepared through the preparation method, the abrasion resistance and the corrosion resistance of the stainless steel wire are greatly improved; machining and forming are easy; a certain damping performance is achieved; the self noise is low; the problems that a steel wire is prone to being corroded, rusted and abraded and large in noise are well solved; and the service life of the low-self-noise stainless steel wire is prolonged.

The invention, which relates to the deep-sea subsurface buoy positioning, provides a three-point type deep-sea subsurface buoy positioning method. Longitudes and latitudes at different positions within response distances of three releasers and corresponding ranging values are obtained; data are introduced into a designed geometric model; and calculation is carried out by a calculation program to obtain calculation values and sketch maps of a longitude, a latitude, and a depth of a weight block. A scientific and effective method that can be implemented simply and conveniently is provided for positioning work in deep-sea subsurface buoy recycling; and only with the three-point positioning, the actual position of the subsurface buoy in water is obtained and then recycling is carried out, so that time needed by recycling is saved to the great extent and the risk of subsurface buoy losing is reduced.

The utility model relates to a sandwich type sound-permeable window structure form of a ship's wind deflector. The main body is a sandwich structure, including inner and outer constrained layers and a sandwich core. The constrained surface layer is made of fiber-reinforced resin-based composite material or titanium alloy, and the core layer is made of viscoelastic material. The constrained surface layer is closely bonded to the core layer. The invention comprehensively considers the requirements of the structure in terms of strength and acoustic characteristics. In addition to satisfying the structural strength, it also has good sound transmission performance, small insertion loss, large damping factor, and high specific strength, which reduces the noise generated under the excitation of surface turbulent pulsation. Self-noise, thereby reducing the signal interference of flow noise to the sonar antenna.

The invention belongs to the technical field of noise elimination, vibration reduction and noise reduction, and relates to a volcanic rock noise elimination tile, in particular to a noise elimination tile made from volcanic rocks and synthetic rubber. The volcanic rock noise elimination tile is composed of a natural volcanic rock hollow frame, multiple natural volcanic rock cones arranged in the natural volcanic rock hollow frame, and a synthetic rubber block for vulcanization and package of an assembled and combined body of the natural volcanic rock hollow frame and the multiple natural volcanic rock cones, wherein outer walls of both the upper surface board and the lower surface board of the natural volcanic rock hollow frame have certain radian; holes of the selected volcanic rocks are formed naturally in a non-uniform manner; the radian of the volcanic rock noise elimination tile is consistent with that of the surface of an underwater moving body; after packaged by the synthetic rubber, the volcanic rock hollow frame and the volcanic rock cones form the noise elimination tile together. The volcanic rock noise elimination tile can absorb sound waves of active sonar, remarkably reduce reflection strength of sound waves of the active sonar, suppress vibration generated by the underwater moving body itself, prevent machine noise inside the underwater moving body from radiating to the underwater moving body, remarkably lower self noise of the underwater moving body, reduce operating range of passive sonar of a detection side and the like.

The invention belongs to the field of signal detection, and provides a photovoltaic hybrid array detection system which is low in self-noise, high in sensitivity, large in dynamic range and strong in anti-interference capacity. According to the technical scheme, the photovoltaic hybrid array detection system comprises a data recording center, data transmission modules, data collecting modules, a light source module, a photovoltaic conversion module, fiber optic hydrophones and optical fibers. On the one hand, the data recording center is responsible for sending control commands to all the data transmission modules. On the other hand, the data recording center is responsible for receiving detection data transmitted by all the data transmission modules and carrying out storage and corresponding processing on the data. The signal collecting modules and the data transmission modules are in data communication through RS485 interfaces or SPI interfaces or in a level matching direct connection mode. The data transmission modules are connected in series in sequence, and the control commands sent by the data recording center are transferred to the data transmission module at the last end in sequence. The photovoltaic hybrid array detection system is mainly applied to gas detection.

The invention discloses a transmitter converting current to voltage. The transmitter comprises a current source circuit, a current converting circuit, and a voltage converting circuit. The current source circuit is used to provide stable direct current for the current converting circuit. The current converting circuit is used to convert an input first current range to a second current range. The voltage converting circuit is used to convert the second current range to a preset voltage range. The transmitter is a universal transmitter which can convert a standard 4-20 mA current signal output by a sensor to a 0-5 V voltage signal which meets input requirements of an analog-digital converter. The transmitter is suitable to be used in operation temperature of 25 DEG C to 85 DEG C, and is small in volume and high in converting precision.

The invention belongs to the technical field of noise elimination, vibration reduction and noise reduction, and relates to a combined-type anechoic tile, in particular to the anechoic tile made of conic vesuvianite, porous light-weight metal material and synthetic rubber. The anechoic tile is formed by the porous light-weight metal material block with certain radian and thickness, conic vesuvianite and the synthetic rubber block used for sulphurating and packaging the porous light-weight metal material block and the conic vesuvianite into an integral structure; the selected vesuvianite and vesuvianite holes are formed naturally, and are uneven; the radian of the porous light-weight metal material block is consistent with the surface radian of an underwater moving body; and the anechoic tile is formed after packaging of the synthetic rubber block. The anechoic tile can absorb acoustic waves of active sonar, remarkably reduces the reflection strength of acoustic waves of the active sonar, can further restraint vibration generated by the underwater moving body, isolates the noise of the machine, radiating to the underwater moving body, inside the underwater moving body, remarkably reduces the self noise of the underwater moving body, and reduces the operating range of passive sonar of the detection party.

The invention provides a dot-matrix sandwich sound-permeable window structure for a ship-used wind deflector, which belongs to the technical field of ship-used acoustics. The marine dome lattice sandwich sound-permeable window structure includes an inner constraining surface layer, an outer constraining surface layer and an intermediate core layer; the core layer is tightly bonded between the inner constraining surface layer and the outer constraining surface layer; The inner constraining surface layer and the outer constraining surface layer are made of carbon fiber reinforced composite material, and the core layer is composed of a three-dimensional lattice layer formed by a collection of one or more three-dimensional lattice structures; the material of the core layer Same material as the inner and outer constraining surfaces. The sound-transmitting window and the air guide cover are integrated, which is convenient for integrated installation and avoids the influence of the installation structure of the split-type sound-transmitting window on the performance of the transducer.

The invention discloses an inflatable water-jet propeller which comprises a pump shell, a nozzle is arranged at one end of the pump shell, an impeller and an inlet runner are arranged in the pump shell, the impeller is arranged between the nozzle and the inlet runner, the impeller is fixed on a shaft capable of driving the impeller to rotate. The inflatable water-jet propeller is characterized in that an inflating device is arranged in the inlet runner; and the inflation device is connected with an air storage device through an air supply pipeline. According to the inflatable water-jet propeller, the cavitation performance of the water-jet propeller is improved, and the cavitation noise of the water-jet propeller is reduced.