227results about How to "Reduce radiated noise" patented technology

A super-regenerative receiver uses controlled Q-quenching and may limit the resonant tank circuit amplitude by loading the tank circuit as soon as regenerative oscillation is detected. An amplitude detector is coupled to the regenerative amplifier and controls a Q loading circuit coupled to the tank circuit of the regenerative amplifier. The amplitude detector turns on the Q loading circuit which then stops the regenerative amplifier from oscillating, and the Q-loading remains on for a brief time to insure that the regenerative amplifier has stopped oscillating. After the brief time, the Q loading circuit is turned off and the regenerative amplifier goes into oscillation again. This cycle repeats controllably over and over, resulting in a lower self-induced noise floor and improved received signal sensitivity. The super-regenerative receiver may be used in the very low frequency (VLF), low frequency (LF), medium frequency (MF), high frequency (HF), very high frequency (VHF) and super high frequency (SHF) ranges to receive continuous wave (CW), amplitude modulated (AM) and frequency modulated (FM) radio signals.

A circuit board area is formed on a front glass substrate of a liquid crystal display (LCD) panel, and driver ICs are mounted in the circuit board section. The driver ICs are electrically connected to an external display control device via a flexible printed circuit board (FPC). A metal foil is attached to one side of the FPC for shielding unnecessary radiating noises. The metal foil has connecting flap portions and the flap portions are fixed to an outer case of a backlight unit with a metal foil tape. The metal foil tape is also bonded to an external frame of an LCD device. As a result, the metal foil is electrically connected with the external frame and the radiating noises are effectively reduced.

The differential transmission cable comprises a cable having at least one pair of differential transmission lines, one or more transmission transformers, and connectors at both ends, the transmission transformer having an integrally sintered laminate structure and a coupling coefficient of 0.65 to 0.98 at 100 MHz, the distance between a center of the transmission transformer and a tip end of the closest connector being within 0.1 m, and the distance between a center of the transmission transformer and a tip end of the farthest connector or between a center of the transmission transformer and a center of the other transmission transformer being 0.5 to 4 m. The transmission transformer is mounted onto a substrate, which is inserted into the connector or a housing of the connector having lands or a positioning holder. After wiring, the connector including the substrate is integrally resin-molded.

Flap side edge noise mechanisms have been addressed in a large number of studies during the last decades. A specific vortex system emanates from the flap side edge due to the static pressure difference between the upper and lower flap surfaces. Such pressure difference leads to a merging between the two vortex systems that are generated on the upper and lower edges of the flap side contour. The present invention intends to show the application of a perforated blade seal (21) at the lower (11) and / or upper (8) side edges of the control surface contour, such as a flap (3), with the purpose of acting as a vortex generator, making difficult for the lower vortex system to move upwards and merge with the upper vortex system. The perforated blade seals (21) are preferably arranged on the inboard and outboard edges of high lift flaps (3).

A spread spectrum clock generation circuit capable of further reducing the electromagnetic wave radiation with a simple configuration has been disclosed and, particularly in a spread spectrum clock generation circuit using a current control oscillator (ICO), a differential signal to which a spread spectrum modulation signal, the period or amplitude of which changes, is added is generated, and the differential signal is applied to the ICO and a clock is generated.

A signal receiver (11) receives an analog signal via a twisted pair cable (31). An A / D converter (12) converts the analog signal to a digital signal. A phase detection unit (14) detects the phase of the digital signal, and generates a reception timing signal. A transmission timing generation unit (15) controls, based on the reception timing signal, timing for a transmission processing unit (16) to output the digital signal such that the reception signal (point A) and a transmission signal (point D) are different in phase by a predetermined degree. The transmission processing unit (16) outputs, in accordance with the timing, a digital signal obtained by performing mapping on data inputted from a connection device (20). A D / A converter (17) converts the digital signal to an analog signal. A signal transmitter (18) transmits the analog signal via a twisted pair cable (32).

A lighting apparatus for visible light communication includes at least one luminaire body and a visible-light-communication-signal-outputting part. The luminaire body includes a light source that includes an LED. The visible-light-communication-signal-outputting part is configured to output a modulation signal to the luminaire body. The luminaire body further includes: a power supply circuit configured to dim the light source; a switch element for modulating an output current that is supplied from the power supply circuit to the light source; a resistor connected in parallel with the switch element; and a photo-coupler configured to receive the modulation signal output from the visible-light-communication-signal-outputting part. The visible-light-communication-signal-outputting part is provided outside the luminaire body, and is configured to transmit the modulation signal via the photo-coupler.

An air cleaner is provided with a housing, a filter element disposed inside the housing for filtrating air introduced into the housing, and an adsorption element disposed in the housing for adsorbing gasified fuel in the housing, the adsorption element including an adsorbing member adsorbing gasified fuel and a frame surrounding the adsorbing member to hold the adsorbing member. The air cleaner further includes a plurality of first fusing projections projecting from one surface of the frame, a plurality of ribs formed to an inner surface of the housing so as to project therefrom and extending laterally and transversely to cross each other, and a plurality of second fusing projections formed to the inner surface of the housing at positions corresponding to the location of the first fusing projections formed to the frame of the adsorption element, each of the second projections being surrounded by a pair of crossing ribs.

A shielding plate is made of a conductive material connected to a ground. The shielding plate is arranged between a photo timer for measuring an amount of the radiation and a radiation-sensitive semiconductor thick film over an entire surface of an effective area for X-ray detection. The shielding plate shields a radiation noise from the photo timer, and thus the radiation noise can be released by connecting the shielding plate to the ground. As a result, the radiation noise from the photo timer which has influence on the radiation detector can be reduced.

A circuit board area is formed on a front glass substrate of a liquid crystal display (LCD) panel, and driver ICs are mounted in the circuit board section. The driver ICs are electrically connected to an external display control device via a flexible printed circuit board (FPC). A metal foil is attached to one side of the FPC for shielding unnecessary radiating noises. The metal foil has connecting flap portions and the flap portions are fixed to an outer case of a backlight unit with a metal foil tape. The metal foil tape is also bonded to an external frame of an LCD device. As a result, the metal foil is electrically connected with the external frame and the radiating noises are effectively reduced.

A driving signal is applied to a plurality of driving electrodes using the driving matrix illustrated in FIG. 5A obtained by removing a row in which a sum of codes is greatest and a column having a transposition relationship with the row in a Hadamard matrix. Distribution of capacitance in intersection portions between a sensing electrode and a plurality of driving electrodes can be obtained using an inverse matrix of the driving matrix illustrated in FIG. 5B. Further, when decoding is performed using an extended matrix obtained by replacing “0” with “−1” in FIG. 5B, it is possible to average noise and to improve an S / N ratio.

The invention provides a method for obtaining engine radiation noise and an engine design optimization method, comprising the steps as follows: calculating main bearing load of an engine crankshaft through establishing a finite element model of an engine, applying the main bearing load of the engine crankshaft on the finite element model of the engine, calculating accelerated velocity of a shell of the engine to be designed, then extracting the surface of the finite element model of the engine, creating a boundary element mesh model of the engine, applying the vibration acceleration on the surface of the shell of the engine on the boundary element mesh model of the engine; finally creating a radiation noise analytical calculation model of the engine and calculating the engine radiation noise according to the radiation noise analytical calculation model of the engine. The method of the invention prolongs the service life of engine and components thereof, reduces finished automobile vibration noise, improves the comfortableness of an automobile and has played excellent effect.

The invention provides a damping vibration-attenuation and noise-reduction method as well as a pored damping sheet. The damping vibration-attenuation and noise-reduction method is characterized in that: the damping sheet which is periodically and uniformly pored is adhered to the outer side of a pipeline or a board, wherein the row distances and the column distances of holes which are opened on the damping sheet are the same. By structurally adhering the periodically pored damping sheet, the vibration and the radiation noise of a structure can be effectively reduced, particularly the vibration-attenuation effect below 800 Hz ranges from 8 to 10 dB. The pored damping sheet disclosed by the invention is simple in structure. Compared with the traditional damping layer, the material and the cost are saved and the structural weight is further lightened.

An element placement check system for checking element placement on a printed wiring board having wiring by which a power supply terminal of an integrated circuit and a power supply decoupling element for the power supply terminal are connected on a mounting surface on which the integrated circuit is mounted, wherein the wiring is connected to a power supply plane for providing a direct current power supply to the power supply terminal through a power supply via hole, including: element distance detecting means detecting a first wire length between the power supply decoupling element and the power supply terminal; power supply via hole distance detecting means detecting a second wire length between the power supply via hole and the power supply terminal; and determination means determining a positional relationship of the power supply decoupling element and the power supply via hole to the power supply terminal based on the first and second wire lengths, thereby providing a check system and a printed wiring board design system capable of checking a connection sequence of a power supply decoupling element such as a bypass capacitor and the power supply via hole connected to the power supply plane feeding a direct current power supply to the power supply terminal as viewed from the power supply terminal of an integrated circuit.

Aircraft are provided with a perforated blade seal at the lower and / or upper side edges of a control surface contour, such as a flap, with the purpose of acting as a vortex generator, thereby making it difficult for the lower vortex system to move upwards and merge with the upper vortex system. The perforated blade seals are preferably arranged on the inboard and outboard edges of high lift flaps.

The invention relates to the technical field of marine power, in particular to a magnetorheological elastomer thrust bearing base dynamic vibration absorber and a use method. The dynamic vibration absorber is arranged on a thrust bearing base and comprises magnet yoke sets, a magnetism isolating support shaft, a magnetic conductive shaft sleeve, magnetorheological elastomers and an electromagnetic assembly. The outer layer of the magnetism isolating support shaft is sleeved with the magnetic conductive shaft sleeve. The two ends of the magnetic conductive shaft sleeve are provided with the parallelly arranged magnet yoke sets correspondingly. The joints of the magnetic conductive shaft sleeve and the magnet yoke sets are provided with the magnetorheological elastomers. At least one electromagnetic assembly is arranged around the part, between the two magnet yoke sets, of the magnetic conductive shaft sleeve. According to the magnetorheological elastomer thrust bearing base dynamic vibration absorber and the use method, longitudinal vibration of the thrust bearing base is controlled effectively, then the transmitting ratio of pulsating force of a propeller through the bearing base to a boat body is lowered, and the purpose of reducing of radiation noise is achieved.

The invention relates to a low noise thrust bearing device for a ship. The low noise thrust bearing device comprises a thrust bearing base, thrust bearing assemblies are installed on the thrust bearing base in the axial direction, one end of each thrust bearing assembly is connected with a prime motor through a high elasticity shaft coupling, and the other end of each thrust bearing assembly is connected with a stern shaft; the thrust bearing base is further fixedly connected with a ship body stern structure; multiple longitudinal vibration isolator assemblies are installed among the thrust bearing assemblies and the thrust bearing base and are all arranged in the axial direction; multiple radial vibration isolator supporting and hanging parts used for supporting connection are further installed among the thrust bearing assemblies and the ship body stern structure and are arranged in the radial direction with the thrust bearing assemblies being the center. The thrust bearing assembliesare in circumferential symmetry after the thrust bearing base is assembled, and the nonuniformity of transferring exciting force of a propulsion axis system ship body structure and vibration responsecaused by the nonuniformity are lowered.

The invention relates to a wind power generating device, in particular to a horizontal-shaft wind machine with a blade tip winglet, more particular to a horizontal-shaft wind machine blade tip tooth-shaped winglet device which has an automatic speed-reduction regulatory function, can improve the wind wheel aerodynamic characteristic, the structural dynamic characteristic, the blade surface dynamic load distribution and the blade tip vortex shedding frequency of the wind machine and can reduce the radiation noise of a wind wheel. The horizontal-shaft wind machine blade tip tooth-shaped winglet device comprises a blade (2), a hub (3), an engine room (4) and a tower base (5), wherein the blade tip of the blade of the wind wheel is provided with a winglet (1) which is in a flat plate shape and is also in a similar triangle shape, and the sloping edge (S) of the blade tip winglet (1) is in a comb shape. The invention improves the combination property of the wind machine by simply installing a winglet in a flat plate shape on the blade tip of the wind machine under the premise of no alteration of the structural parameters of an original wind machine; the blade tip winglet adopts a flat plate type structure; and the invention has the advantages of simple structure, short process flow, less working procedure, low manufacturing cost and simple installation.

Aiming at the problem of the electromagnetic noise of a switch power supply, the invention starts from two aspects of electromagnetic noise attenuation and insulation and electromagnetic noise forming source blockage and lays stress on destroying the basic condition generating the electromagnetic noise so as to eliminate the noise. A basic idea is as follows: the voltage and the current variable amount of a circuit is smoothed by a physical law that inductive current in a switch power supply can not be changed suddenly and the mutual match of the following current of a plurality of inductors, thereby eliminating or weakening the electromagnetic noise of the power supply. The conducted noise and the radiated noise output by the switch power supply can be reduced to a lower degree and approach the output noise level of a linear power supply by combining a combined noise eliminating technology on the basis of the traditional electromagnetic noise inhibiting technology, and the invention provides a technical way for replacing the linear power supply by the switch power supply.

A printed circuit board includes a printed circuit board, a semiconductor device mounted on the printed circuit board, a capacitor element mounted on the printed circuit board 2, a ground conductor plane to which a ground terminal of the semiconductor device is connected, and first and second power source conductor planes which are arranged so as not to contact with each other. The second power source conductor plane and the ground conductor plane are arranged so as to oppose to each other to form a planar capacitor. The printed circuit board has a first connecting conductor which connects a power source terminal of the semiconductor device with the second power source conductor plane, and a second connecting conductor which connects the first power source conductor plane with the second power source conductor plane through a first terminal of the capacitor element. Thereby, an electromagnetic radiation noise is reduced.

An air cleaner is provided with a housing, a filter element disposed inside the housing for filtrating air introduced into the housing, and an adsorption element disposed in the housing for adsorbing gasified fuel in the housing, the adsorption element including an adsorbing member adsorbing gasified fuel and a frame surrounding the adsorbing member to hold the adsorbing member. The air cleaner further includes a plurality of first fusing projections projecting from one surface of the frame, a plurality of ribs formed to an inner surface of the housing so as to project therefrom and extending laterally and transversely to cross each other, and a plurality of second fusing projections formed to the inner surface of the housing at positions corresponding to the location of the first fusing projections formed to the frame of the adsorption element, each of the second projections being surrounded by a pair of crossing ribs.

An electronic apparatus is provided which causes less radiation noise leakage through an aperture with a shielding box in a compact size. The apparatus has a shielding box encasing a printed circuit board connected to a cable. The shielding box has a cable-regulating portion which seals the aperture of the shielding box for leading out the cable connected to the printed board and presses the cable against the bottom plate of the shielding box. Thereby the radiation noise caused by common-mode current in the cable is also reduced.

The present invention provide a kind of X-ray detection system, which includes one detector for detecting X-ray passing through inspected body and generating analog electric signal corresponding to the X-ray for each channel; one data acquisition unit comprising several circuit modules with circuits in the number corresponding to the channel number to convert the analog signals into digital signal for output; and one phase control unit for controlling the phase the circuit modules in the data acquisition unit and dividing the circuit modules into several groups operating synchronously with the clock signal possessing different phases in different groups.

The invention belongs to the field of ship design, in particular to a novel shaft-less pump-jet thruster and an underwater vehicle containing the thruster. By arranging the propeller in front of the rudder, the uniformity of the flow field at the paddle surface can be improved, and the propeller radiated noise and the hull radiated noise caused by the exciting force of the propeller can be effectively reduced. The longer transmission shaft system is omitted and the vibration of the shaft system is basically eliminated. The vortex eliminating tail fin can reduce the vortex intensity in the wakeflow, absorb the wake flow energy, and avoid cavitation. The axially-free pump propeller of the invention can be installed on various equipments such as unmanned and manned underwater vehicles, submarines, and the like, and has wide application prospects.

A printed circuit board includes a first semiconductor package on a first surface layer of a printed wiring board and a second semiconductor package on a second surface layer where a bus signal is transmitted from the first to the second semiconductor package. A first bus wiring path from a signal terminal on an inner circumference side of the first semiconductor package via a via hole and the second surface layer to a signal terminal on an outer circumference side of the second semiconductor package and a second bus wiring path from a signal terminal on an outer circumference side of the first semiconductor package via the second surface layer and a via hole to a signal terminal on an inner circumference side of the second semiconductor package are provided, thus securing a return current path for a signal current and realizing a high density wiring while suppressing radiation noise.

The invention relates to a sucker for road sweeping equipment and the road sweeping equipment. The sucker for the road sweeping equipment comprises a sucker body (1), a suction pipe (5) and a driving part (7), wherein the suction pipe (5) is movably arranged on the sucker body (1) along the width direction of the road sweeping equipment; and the driving part (7) is used for driving the suction pipe (5) to move along the sucker body (1). When the road sweeping equipment works, the driving part can be flexibly controlled to adjust the position of the suction pipe along the width direction of the road sweeping equipment according to the garbage distribution condition and garbage weight on the road, so that pressure distribution in a sucking chamber of the sucker body is changed, a position with high vacuum degree in the sucking chamber is aligned with a pavement area with centralized garbage or heavy garbage, the sucking performance of the sweeping equipment can be improved under the condition that the fan power is not increased, and the energy consumption and radiation noise of the equipment can be effectively reduced.

The invention discloses a method for calculating the radiation noise generated by the pipe wall of a water-filling pipeline during the reverberation method. According to the method, firstly, the radiation noise and the jet noise, generated due to the vibration of the pipe wall of a water-filling pipeline, are measured based on the reverberation method. Secondly, only the jet noise of the water-filling pipeline is measured and obtained based on the reverberation method, so that the radiation noise of the underwater water-filling pipeline generated during the vibration process is obtained. The above method is simple in calculation and high in efficiency. The radiation noise and the jet noise, generated by the pipe wall of the water-filling pipeline in a single non-noise-elimination pool and measured based on the reverberation method, is subtracted by the jet noise of the water-filling pipeline measured based on the reverberation method. In this way, the radiation noise of the water-filling pipeline generated during the vibration process is obtained.

The invention discloses a centrifugal fan volute employing granular damping vibration attenuation. The centrifugal fan volute comprises a volute body, wherein the volute body is provided with an air inlet (4); a centrifugal fan (7) is arranged in the volute body and is driven by a motor (8). The centrifugal fan volute is characterized in that the volute body consists of an inner volute (1) and an outer volute (2); a vibration attenuation and noise reduction chamber is formed between the inner volute (1) and the outer volute (2) and is filled with damping vibration attenuation granules (6). According to the centrifugal fan volute, the chamber between the inner volute and the outer volute is filled with spherical granules, the non-elastic collision and the friction between the granules and between each granule and the wall of the chamber are caused by the vibration of the inner volute, the energy is consumed, and the aim of vibration attenuation is achieved; meanwhile, the radiation noise of the volute can be reduced. The centrifugal fan volute can be applied to the industrial fields of energy power, petrochemical industry, petrochemical industry and the like, and the field of national defense and military industry.

An airplane propelled by a turbine engine having at least one fan, the turbine engine being integrated in the rear of a fuselage of the airplane, extending it rearwards, the airplane further including at least one acoustic baffle forming panel connected to the fuselage of the airplane and arranged below the turbine engine.