38results about How to "Improved noise attenuation" patented technology

A filter network having the capability of establishing multiple, tunable notch frequencies. A notch filter path is established for each notch frequency and includes a bandpass filter and inverter. An input RF signal covering a wide frequency range is applied to all the notch filter paths. Each notch filter path produces an output spectrum that is equal in magnitude and 180.degree. out of phase with respect to an undesired frequency spectrum. A combiner circuit combines the outputs of each notch filter path in parallel with the RF input signal to produce an RF output signal with all desired spectra unchanged and all undesired spectra attenuated.

A device comprising a voice activity detector for detecting voice activity in a speech signal using digital data formed on the basis of samples of an audio signal. The voice activity detector comprises a first element adapted to examine whether the signal has a highpass nature. The voice activity detector also comprises a second element adapted to examine the frequency spectrum of the signal. The voice activity detector is adapted to provide an indication of speech when the first element has determined that the signal has a highpass nature or the second element has determined that the signal does not have a flat frequency response.

A liner assembly for a fan case includes a noise attenuation layer covered by a face sheet. The face sheet includes openings to the underlying noise attenuation layer. The face sheet and noise attenuation layer include acoustically transparent joints. The noise attenuation layer includes a first side joined to a second side at a seam by an adhesive strip. The adhesive strip bonds the first side to the second side without filling any chambers. The face sheet includes a joint filled with an adhesive providing the desired uninterrupted surface within the fan case. Openings are formed through the joint and the adhesive to communicate with the underlying noise attenuation layer. The joint and seam become essentially transparent acoustically to improve noise attenuation performance.

A flexible noise attenuating cutting line for use in rotary vegetation trimmers formed by extruding a pair of molten monofilament strands in proximate disposition through a rotating die so as to form a line comprised of two monofilament polymer strands bonded together in a twisted disposition about a central longitudinal axis so as to define a pair of substantially V-shaped opposed troughs extending helically along and about the line.

This method comprises the following steps in the frequency domain:a) estimating a probability that speech is present;b) estimating a spectral covariance matrix of the noise picked up by the sensors, this estimation being modulated by the probability that speech is present;c) estimating the transfer functions of the acoustic channels between the source of speech and at least some of the sensors relative to a reference constituted by the signal picked up by one of the sensors, this estimation being modulated by the probability that speech is present;d) calculating an optimal linear projector giving a single combined signal from the signals picked up by at least some of the sensors, from the spectral covariance matrix, and from the estimated transfer functions; ande) on the basis of the probability that speech is present and of the combined signal output from the projector, selectively reducing the noise by applying variable gain.

An automotive exhaust gas noise attenuating device which treats exhaust gas emissions, the device having (a) a ceramic substrate for passing an automotive exhaust stream therethrough, the substrate having (i) an inlet face and an outlet face with a plurality of aligned thin porous channel walls defining channels extending between the faces, and (ii) a three dimensional aspect relationship where depth of the substrate between said faces is generally the same as either the height of width of a face, the substrate having first alternates of the channels blocked at the outlet face and second alternates of the channels blocked at the inlet face to promote lateral flow through the porous walls between each first channel and a multiple of second alternate channels while permitting laminar flow within such channels; (b) hollow shell pellets packed into and trapped in at least some of the first alternate channels which cooperate to define porous Darcy flow surfaces therein; and (c) dolomitic carbonate and catalyzing material on or in the surfaces of the channel walls and Darcy flow surfaces.

The invention relates to a silencer being designed with sound absorptive material (13, 23) and a conduit section (1, 2) with one or more conduits (1) for leading gas flow into the silencer and with one or more outlets (2) for leading gas form the silencer. The sound absorptive material (13, 23) and the conduit section (1, 2) constitutes a protrusion extending from part of an outer shell (4) such as from an end cap (5, 6) constituting part of the shell for the silencer, or from an internal member, such as a baffle (9, 10) possibly separating at least two through-flowed chamber (12) of the silencer. Not-through-flowed cavities (17, 27) are arranged essentially adjacent to or at least partly surrounding said sound absorptive material (13, 23), thereby constituting one or more resonators acoustically communicating with said at least one through-flowed chamber. The silencer may also be designed so as to act as a spark-arrestor. Also, the invention relates to a combustion engine provided with such silencer.

Embodiments of a noise attenuation device comprise a plurality of stacked plates that form channels to reduce energy in a flow of working fluid that transits the noise attenuation device. In one embodiment, the stacked plates include plates having openings in different patterns. Orientation of the plates align the patterns in a housing to form the channels. In one example, the plates are disposed in a fluid coupling (e.g., a valve and / or flow regulator) that includes a throttling element. The plates are spaced apart from the throttling element, thereby permitting the working fluid to flow through all of the channels whether the throttling element is fully or partially open.

A liner assembly for a fan case includes a noise attenuation layer covered by a face sheet. The face sheet includes openings to the underlying noise attenuation layer. The face sheet and noise attenuation layer include acoustically transparent joints. The noise attenuation layer includes a first side joined to a second side at a seam by an adhesive strip. The adhesive strip bonds the first side to the second side without filling any chambers. The face sheet includes a joint filled with an adhesive providing the desired uninterrupted surface within the fan case. Openings are formed through the joint and the adhesive to communicate with the underlying noise attenuation layer. The joint and seam become essentially transparent acoustically to improve noise attenuation performance.

A filter assembly configured for acoustic dampening for use with compressor assemblies such as oxygen concentrators including a compartmented housing member having an inlet opening, an outlet opening, a filter member, and a plurality of noise attenuating members positioned and located therewithin. The configuration of the compartmented housing member in conjunction with the positioning and location of the filter member and the noise attenuating members therewithin all contribute to absorb and dissipate any sound waves generated within the housing member due to air flow movement therethrough. This substantially reduces and minimizes noise associated with the present filter assembly.

The suction arrangement of the present invention is for a hermetic compressor of the type which includes a hermetic shell; a cylinder block defining, in a single piece, a shell portion and a compression cylinder having an end opened to the exterior of the hermetic shell and closed by a valve plate; a head affixed to the cylinder block onto the valve plate so as to define, with the latter, at least one suction chamber receiving refrigerant gas from a gas inlet pipe external to the hermetic shell. The suction arrangement of the present invention comprises a gas inlet duct defined through the shell portion and through the valve plate and having an outer end hermetically coupled to the gas inlet pipe and an inner end opened to the suction chamber.

A laminate composite wallboard panel is disclosed having multiple layers whose cross sections may contain internal and external non-uniformities and whose surfaces may be rough and non-uniform. The wallboard panel is similar in size and weight to a standard gypsum panel and can be handled and installed in a manner similar to such a panel. The wallboard panel also provides high degrees of noise attenuation, thermal insulation, fire resistance, shear strength, mold resistance and moisture resistance.

An improved de-ghosting method and system that utilizes multi-component marine seismic data recorded in a fluid medium. The method makes use of two types of data: pressure data that represents the pressure in the fluid medium, such as sea water, at a number of locations; and vertical particle motion data that represents the vertical particle motion of the acoustic energy propagating in the fluid medium at a number of locations within the same spatial area as the pressure data. The vertical particle motion data can be in various forms, for example, velocity, pressure gradient, displacement, or acceleration. A spatial filter is designed so as to be effective at separating up and down propagating acoustic energy over substantially the entire range of non-horizontal incidence angles in the fluid medium. The spatial filter is applied to either the vertical particle motion data or to the pressure data, and then combined with the other data to generate pressure data that has its up and down propagating components separated.

An assembly for use in continuously forming a plurality of lengths of flexible noise attenuating cutting line for use in rotary vegetation trimmers. The assembly includes a breaker plate having a conically shaped inner portion and a planar outer portion. A plurality of extrusion dies are disposed in the outer portion wherein each die defines a die hold configuration at its lower end for the extrusion of one or more monofilament polymer strands therethrough, and a drive assembly is provided for rotating each of the dies at a predetermined speed such that upon directing a flow of molten monofilament polymer material onto the breaker plate, the material is directed from the inclined central portion onto the planar outer portion where it is extruded through the rotating dies to create a plurality of twisted strands of polymer material that upon cooling, stretching and heating, define lengths of flexible noise attenuating cutting line.

A vibration isolation section (20) for use in a seismic streamer system, the section (20) including: a resilient sheath (30) arranged to be connected end-to-end in a seismic streamer (16) system and receive axial loads transmitted through the system, wherein the resilient sheath (30) is configured to stretch upon receiving an axial load and substantially convert the axial load into a radial stress; and a first support structure (42) housed within a first portion (31) of the resilient sheath(30), the first support structure (42) including one or more members having substantially constant diameter under load which provides a reaction to the radial stress, thereby reacting to the received axial load; and a second support structure housed at least in part within a second portion (33) of the resilient sheath(30), the second support structure including an enclosed fixed volume fluid filled flexible chamber (46) at least partially housed within the second portion (33) of the resilient sheath (30), the fluid filled flexible chamber (46) providing a reaction to the radial stress thereby reacting to the received axial load.

The suction arrangement of the present invention is for a hermetic compressor of the type which includes a hermetic shell; a cylinder block defining, in a single piece, a shell portion and a compression cylinder having an end opened to the exterior of the hermetic shell and closed by a valve plate; a head affixed to the cylinder block onto the valve plate so as to define, with the latter, at least one suction chamber receiving refrigerant gas from a gas inlet pipe external to the hermetic shell. The suction arrangement of the present invention comprises a gas inlet duct defined through the shell portion and through the valve plate and having an outer end hermetically coupled to the gas inlet pipe and an inner end opened to the suction chamber.

A suction muffler for a reciprocating hermetic compressor, comprising a hollow body (10) provided with a gas inlet and a gas outlet (12, 14), which are respectively in fluid communication with the gas supply to the compressor and with a suction side thereof, said hollow body (10) defining a plurality of chambers comprising an innermost first acoustic chamber (50) in fluid communication with the gas outlet (14) of the hollow body (10), and a second acoustic chamber (51) surrounding at least partially the first acoustic chamber (50) and in fluid communication with at least one of the parts defined by said first acoustic chamber (50) and by the gas inlet (12) of the hollow body (10).

A filter assembly for use with compressor assemblies such as oxygen concentrators, ventilators and other breathing apparatus including a compartmented housing member having at least one inlet opening, an outlet opening, a filter member, and an adjustment member associated with the at least one outlet opening for varying the size of the at least one outlet opening for adjusting the amount of ambient air entering the filter assembly.

The present invention relates to a flow regulator unit having an insert housing which can be disposed between an inflow side pipe section and an outflow side pipe section of a sanitary water pipe.At least one flow regulator having an adjustment core is provided in the housing so as to define an annular passage between itself and the peripheral wall surrounding the adjustment core. And a throttle made of an elastic material is provided in the annular passage. The section fluid defining at least one adjustment gap between itself and at least one adjustment forming portion provided on the adjustment core and additionally or alternatively disposed on the circumferential wall.The adjustment gap can be changed under the pressure of the water flowing through.According to the present invention, at least one of the inserts is connected to the upstream or downstream of the flow regulator unit in a flow direction, the at least one insert having a grid structure or a net formed by a tab intersecting each other at a cross node Grid structure, which defines a through-flow opening between itself.

A non-structural multi-part panel including at least two layers, a first layer of foamed material and a second layer applied to at least one side of the first layer, the second layer of cellulosic material.

A direct current motor for a vehicle, according to the present invention, comprises: a cover assembly (10); a yoke assembly (30) having a lower housing (40) coupled with the cover assembly (10), and aplurality of excitation poles (31) arranged inside the cover assembly (10); an armature assembly (20) comprising an armature core (22) and upper and lower insulators (23, 24), the armature core (22)having a plurality of teeth (22A) around which coils (21) interacting with the excitation poles (31) are wound, and the upper and lower insulators (23, 24) coupling to the upper and lower portions, respectively, of the armature core (22); a commutator (50) installed on the lower side of the armature core (22) and having commutator segments (51) of which the number corresponds to the number of theexcitation poles (31); a brush holder (60) arranged on the inner side of the lower housing (40) and comprising a brush (61) selectively making contact with the commutator (50) according to the rotation of the armature assembly (20); a rotational shaft (70) having the armature core (22) and the commutator (50) coupled thereto so as to rotate therewith; an up / down / left / right vibration and noise dampening buffer means (80) installed on the upper and lower portions, respectively, of the rotational shaft (70); a brush holder left / right vibration and noise dampening buffer means (90) installed on the brush holder (60) so as to be insertedly installed in a yoke cylindrical body (32) constituting the yoke assembly (30); a grounding means (110) comprising a power supply connector (100) coupled to aconnector receiving part (63) formed on a support (62) of the brush holder (60); and an insulating means (120) installed so as to make surface-contact with the upper side of the commutator (50) installed in the center of the support (62) of the brush holder (60).

A liner assembly includes a plurality of aligned passages providing a large open area combined with openings much smaller than a length of the passages. The plurality of passages are disposed parallel with each other and include an opening transverse to incident sound waves. The passages are separated by walls and are blocked at an end distal from the openings. Sound waves incident on a face of the liner enter the passages and are dissipated by viscous losses. Sound energy is further dissipated as thermal energy to the walls of the passages. The long narrow passages provide the desired visco-thermal losses for sound energy in a broad frequency range.

A non-structural multi-part panel including at least two layers, a first layer of foamed material and a second layer applied to at least one side of the first layer, the second layer of cellulosic material.

An improved de-ghosting method and system that utilizes multi-component marine seismic data recorded in a fluid medium. The method makes use of two types of data: pressure data that represents the pressure in the fluid medium, such as sea water, at a number of locations; and vertical particle motion data that represents the vertical particle motion of the acoustic energy propagating in the fluid medium at a number of locations within the same spatial area as the pressure data. The vertical particle motion data can be in various forms, for example, velocity, pressure gradient, displacement, or acceleration. A spatial filter is designed so as to be effective at separating up and down propagating acoustic energy over substantially the entire range of non-horizontal incidence angles in the fluid medium. The spatial filter is applied to either the vertical particle motion data or to the pressure data, and then combined with the other data to generate pressure data that has its up and down propagating components separated.