39 results about "Broad band noise" patented technology

In an air conditioner, reverse inhalation is prevented while broad band noise and wind sound are reduced.There are provided a projection 12b arranged at the leading end of a stabilizer 12 on the downstream side of an air stream F flowing along a surface 12a of the stabilizer opposing an impeller so as to protrude toward the impeller to define the shortest distance to the impeller, and a plurality of grooves 12e or projections provided on the opposing surface on the upstream side of the projection 12b so as to disturb the air stream flowing along the opposing surface 12a. The positions of the grooves 12e or the projections are arranged apart in a rotational axis direction E. A plurality of convex portions are provided so as to disturb an air stream flowing along a surface of a casing opposing the impeller, and the positions of the convex portions are arranged apart in the rotational axis direction of the impeller.

In an air conditioner, reverse inhalation is prevented while broad band noise and wind sound are reduced. A projection arranged at the leading end of a stabilizer on the downstream side of an air stream flowing along a surface of the stabilizer opposing an impeller and protrudes toward the impeller to define the shortest distance to the impeller. A plurality of grooves or projections are provided on the opposing surface on the upstream side of the projection to disturb the air stream flowing along the opposing surface. The positions of the grooves or the projections are arranged apart in a rotational axis direction. A plurality of convex portions are provided to disturb an air stream flowing along a surface of a casing opposing the impellers. The positions of the convex portions are arranged apart in the rotational axis direction of the impeller.

The invention discloses a sound-insulating environment-friendly material used for decoration and a production method of the sound-insulating environment-friendly material used for decoration. The sound-insulating environment-friendly material comprises a hard sound-insulating layer, a sound-absorbing layer and a protective layer, wherein the sound-absorbing layer is arranged between the hard sound-insulating layer and the protective layer, the hard sound-insulating layer is arranged on the face opposite to an internal space, the protective layer is arranged on the face close to the internal space, and lamination bulges are arranged on the hard sound-insulating layer, so that effects on an external space are reduced, and the lamination bulges can reduce resonance between a wall and the hardsound-insulating layer; and the sound-absorbing layer comprises two layers of foamed polypropylene thin layers and a lamination fiber layer arranged between the two layers of foamed polypropylene thin layers, the protective layer is a foamed polypropylene sheet, and the lamination fiber layer is provided with winding small holes which communicate, thus a good effect of attenuating high-frequencynoise can be achieved, and closed hole structures of the foamed polypropylene sheet can insulate noise from low and medium frequency to medium and high frequency, so that broad-band noise is insulatedand absorbed.

A silencer for rotation-type compressor is composed of an internal silencer with the exhaust space for the gas as cold medium of compressing chamber and mounted to main bearing of crankshaft, and an external silencer with the exhaust space for the gas as cold medium of internal silencer and mounted above the internal silencer. It can reduce the broad-band noise and particular-frequency noise and prevent the increasement in input pressure of compressor.

The present inventive concept for bistatic or monostatic radar utilization discloses a method and a system for unambiguous range resolution utilizing an ultra wide-band signal, generally a wide-band noise signal which may be continuous bandwidth limited white or colored noise. The noise signal is typically generated and radiated by a transmitting antenna covering the entire reception range of a receiving sparse antenna. An echo signal is received by the receiving antenna. By means of a selected auto-correlation function defining the wide-band noise signal power spectrum, the convolution of the radiated output signal and the received echo input signal will give the target range information.

A method and apparatus are provided for the removal of significant broad-band noise from waveforms acquired for time domain network analysis. The method may include the steps of providing the noisy waveform as an input waveform, determining a frequency domain noise shape associated with the input waveform, calculating a wavelet domain noise shape from the frequency domain noise shape, calculating a discrete wavelet transform of the input waveform to form a wavelet domain waveform, and estimating the noise statistics from the wavelet domain waveform. A threshold may be calculated from the estimated noise statistics and the wavelet domain noise shape, and the threshold may be applied to the wavelet domain waveform to form a denoised wavelet domain waveform. Finally, an inverse discrete wavelet transform of the denoised wavelet domain waveform may be calculated to form a denoised waveform.

The invention discloses a line to decrease noise for Broad Band and manufacture method. The sound line has the noise elimination hole which is distributed randomly and the size is changed continuously. So it can decrease the noise of broad frequency noise. Because of whole forming, it can not generate the noise dispersion phenomena caused by the sound line joint to influence the noise decreasing effect. In process of Broad Band noise decreasing line, it can get the noise frequency and corresponding noise intension by value simulation of test and get the size range, changing interface and density of noise elimination hole; also it distributes the hole on the sound line basal board to have the good noise decreasing effect.

The invention relates to a broad-band noise insulation honeycomb plate. The honeycomb plate is formed by sequentially bonding a first pore plate, a first honeycomb core, an elastic film, a second honeycomb core and a second pore plate, wherein a plurality of first cavities are distributed in the first honeycomb core; a plurality of second cavities in one-to-one correspondence to the first cavities are distributed in the second honeycomb core; first micro through pores communicating with the first cavities are distributed in the first pore plate; second micro through pores communicating with the second cavities are distributed in the second pore plate. The honeycomb plate can meet the light-weight requirement and can also insulate broad-band noises.

An AM / FM radio system for a vehicle that is selectively impedance matched to the particular tuned frequency of interest so that noise received by other frequencies does not affect the received signal. The radio system includes an HMI allowing a user to select an AM or FM radio station and a radio tuner responsive to a signal from the HMI identifying the selected radio station. The tuner tunes the radio system to the radio station, and provides a signal to the HMI identifying the radio station. The HMI places a message on a vehicle bus identifying the radio station that the radio tuner is tuned to. An antenna controller receives the message from the vehicle bus to selectively control an impedance matrix to provide impedance matching for the selected radio station frequency. The antenna controller also selectively tunes antenna radiating elements to the particular tuned frequency.

A kitchen ventilator with a multi-layer honeycomb noise filtration device comprises a kitchen ventilator body and the honeycomb noise filtration device capable of eliminating noise. The honeycomb noise filtration device is assembled in the kitchen ventilator body. A plurality of through holes for eliminating the noise are distributed in the honeycomb noise filtration device. The honeycomb noise filtration device is provided with a plurality of layers of honeycomb plates. The honeycomb plates are assembled in the kitchen ventilator body. The kitchen ventilator with the multi-layer honeycomb noise filtration device has the advantages that specific single-frequency noise or specific multi-frequency noise reduction is implemented by adjusting combination of the diameters of the different through holes, minimum distances between the edges of the adjacent through holes or the distance between the honeycomb noise filtration device and the kitchen ventilator body; the kitchen ventilator has the advantages of low cost and high reliability; the specific single-frequency noise or wide-band noise can be reduced effectively, the noise-reduction frequency range is wide, and the multi-frequency noise can be reduced.

To solve the problems with the prior art that a multi-microphone array cannot inhibit broad-band noises well and cannot be used in the increasingly widespread broad-band communication, embodiments of the present invention disclose a method, a device and a system for eliminating noises with multi-microphone array. The method according to an embodiment of the present invention comprises according to the number of different spacings between each of pairs of microphones of the multi-microphone array, dividing a full frequency band into the same number of sub-bands; decomposing signals of each of the pairs of microphones with the different spacings into a corresponding one of the sub-bands, wherein the larger the spacing between each pair of microphones is, the lower the frequencies of the sub-band into which the signals of the pair of microphones are decomposed will be; adaptively reducing the noises in the decomposed signals of each of the pairs of microphones with the different spacings in the corresponding sub-band to obtain noise-reduced signals for each of the sub-bands; and synthesizing the noise-reduced signals of each of the sub-bands to obtain a signal in which the noises have been reduced with the multi-microphone array in the full frequency band. The embodiments of the present invention can be used in scenarios of hands-free video calls.

The present invention discloses a method for communication in digital user line techniques. Said method comprises the following steps: obtaining communication performances parameters; a first transmit-receiver device and a second transmit-receiver device performing communications by adopting preconcerted communication rules after the communication performances parameters having reached or exceeding preconcerted values, wherein the preconcerted communication rules are respectively set at the first transmit-receiver device and the second transmit-receiver device. The present invention also discloses a transmit-receiver device for communication in digital user line techniques. According to the present invention, bit tables and gains tables are preconcerted in advance and then stored respectively at the first transmit-receiver device and the second transmit-receiver device. When large broad band noises (such as crosstalk) occur, a quick switching between the bit tables and the gains tables determined in advance is available by utilizing simple message or inquiring-replying mechanism. Since exchanging of bit tables and gains tables is not necessary, the technical scheme in accordance with the present invention is characterized in its quick switching velocity and high reliability. Furthermore, the present invention can improve the spectrum efficiency.

A kitchen ventilator with an air bellow having a noise filtration function comprises a kitchen ventilator body and the air bellow capable of eliminating multi-frequency noise. The air bellow is assembled into the kitchen ventilator body, and is arranged as a panel with a plurality of through holes for eliminating the multi-frequency noise. The kitchen ventilator has the advantages that internal space of the kitchen ventilator can be utilized effectively, minimized dimensional design can be realized, and overall weight can be reduced; the noise can be reduced at or near a noise source, namely afan; the multi-frequency noise reduction is implemented by adjusting combination of the diameters of the different through holes, minimum distances between the edges of the adjacent through holes, regional distribution of the through holes of the panel, or the distance between the air bellow and the kitchen ventilator body; the kitchen ventilator has the advantages of low cost and high reliability; narrow-band noise and wide-band noise can be reduced effectively.