39 results about "Broad band noise" patented technology

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.

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.