372 results about "Acoustic noise reduction" patented technology

An aircraft engine nacelle comprises: (a) an inlet lip and a skin having internal and external surfaces; (b) a noise abatement structure such as an acoustic panel located on the internal surface of the nacelle skin; and (c) an electrically powered de-icing system located on the external surface of the nacelle skin and in electrical connection to a power source. A method for de-icing and abating noise from an aircraft nacelle comprises: (a) providing a noise abatement structure such as an acoustic panel located on the internal surface of the nacelle skin; (b) providing an electrically powered de-icing system on the external surface of the nacelle skin; and (c) applying an electric current to the electrically powered de-icing system. The nacelle skin may be a perforated skin, and the de-icing system comprises a wire mesh bonded to the external surface of the perforated skin. The method and nacelle permit the use of noise abatement structures such as acoustic panels for noise reduction while advantageously avoiding detrimental high temperatures associated with conventional de-icing systems.

The invention provides a method for manufacturing a powertrain component enclosure member, including the steps of: (A) positioning at least one insert into a mold, wherein the insert is provided with a coating to prevent bonding between the insert and the casting material; and (B) casting a wall of the powertrain component enclosure member in the mold around the insert such that a major portion of the insert is substantially non-bonded with the casting material to provide a proper interfacial boundary with the casting material for damping.

A speech signal processing system combines acoustic noise reduction and echo cancellation to enhance acoustic performance. The speech signal processing system may be used in vehicles or other environments where noise-suppressed communication is desirable. The system includes an adaptive beamforming signal processing unit, an adaptive echo compensating unit to reduce acoustic echoes, and an adaptation unit to combine noise reduction and adaptive echo compensating.

A system for detecting noise in a signal received by a microphone array and a method for detecting noise in a signal received by a microphone array is disclosed. The system also provides for the reduction of noise in a signal received by a microphone array and a method for reducing noise in a signal received by a microphone array. The signal to noise ratio in handsfree systems may be improved, particularly in handsfree systems present in a vehicular environment.

A method and apparatus is disclosed for acoustic noise reduction using fan speed control. The acoustic noise reduction using fan speed control includes a plurality of temperature detectors disposed at a plurality of locations within an electronics equipment enclosure, each detector having an associated setpoint temperature. An error value is determined for each temperature detector, the error consisting of the difference between the detected temperature and the associated setpoint temperature. The maximum error among all error values is then identified and the operating speed of a cooling fan in is set in response to this maximum error. Advantages include providing a fan speed directly related to electronics temperature which inherently accounts for higher ambient temperatures, enclosure altitude, electronics power consumption, and air filter clogging. The acoustic noise reduction using fan speed control is particularly useful for overcoming the need to overcompensate fan speed, thereby resulting in higher than necessary noise levels in order to accommodate worse-case conditions known in the art.

The system provides a technique for suppressing or eliminating tonal noise in and input signal. The system operates on the input signal at a plurality of frequency bins and uses information generated at a prior bin to assist in calculating values at subsequent bins. The system first identifies peaks in a signal and then determines if the peaks are from tonal effects. This can be done by comparing the estimated background noise of a current bin to the smoothed background noise of the same bin. The smoothed background noise can be calculated using an asymmetric IIR filter. When the ratio of the current background noise estimate to the currently calculated smoothed background noise is far greater than 1, tonal noise is assumed. When tonal noise is found, a number of suppression techniques can be applied to reduce the tonal noise, including gain suppression with fixed floor factor, an adaptive floor factor gain suppression technique, and a random phase technique.