111results about How to "Improve Noise Cancellation" patented technology

An active noise cancellation system includes a series of features for more effective cancellation, greater reliability, and improved stability. A particular feature adapted for headset systems includes locating a residual microphone radially offset from the center of a sound generator to detect a signal more similar to that incident upon the eardrum of the user. In addition, an open back headset design includes perforations on the side of the headset instead of the back, so that the perforations are less susceptible to inadvertent blockage. The system also includes a mechanism for detecting changes in the acoustic characteristics of the environment that may be caused, for example, by pressure exerted upon the earpieces, and that may destabilize the cancellation system. The system automatically responds to such changes, for example, by reducing the gain or the frequency response of the system to preserve stability. The system further includes other methods for detecting imminent instability and compensating, such as detecting the onset of signals within enhancement frequencies characteristic of the onset of instability, and adjusting the gain or frequency response of the system or suppressing the enhanced signals. The system further includes a mechanism for conserving battery life by turning the system off when sound levels are low, or adjusting the power supply to the system to correspond to the current power requirements of the system.

Electronic probe devices are formed of a conductive loaded resin-based material. The conductive loaded resin-based material comprises micron conductive powder(s), conductive fiber(s), or a combination of conductive powder and conductive fibers in a base resin host. The ratio of the weight of the conductive powder(s), conductive fiber(s), or a combination of conductive powder and conductive fibers to the weight of the base resin host is between about 0.20 and 0.40. The micron conductive powders are formed from non-metals, such as carbon, graphite, that may also be metallic plated, or the like, or from metals such as stainless steel, nickel, copper, silver, that may also be metallic plated, or the like, or from a combination of non-metal, plated, or in combination with, metal powders. The micron conductor fibers preferably are of nickel plated carbon fiber, stainless steel fiber, copper fiber, silver fiber, or the like.

A noise canceling system comprises a microphone (103) generating a captured signal and a sound transducer (101) radiating a sound canceling audio signal in the audio environment. A feedback path (109) from the microphone (103) to the sound transducer (101) comprises a non-adaptive canceling filter (115) and a variable gain (117) and receives the captured signal and generates a drive signal for the sound transducer (101). A gain detector determines a secondary path gain for at least part of a secondary path of a feedback loop. The secondary path may include the microphone (103), the sound transducer (101), and the acoustic path therebetween but does not include the non-adaptive canceling filter (115) or the variable gain (117). A gain controller (121) adjusts the gain of the variable gain (117) in response to the secondary path gain. The system uses simple gain estimation and control to efficiently compensate for variations in the secondary path to provide improved stability and noise canceling performance.

The invention discloses a method for eliminating noise of a long-distance microphone array and a noise-eliminating system. In the invention, the signals collected from two microphones are treated with respect to beam forming, and then the intensified target phonetic signals and the weakened target phonetic signals are obtained; whether target phonetic signals exist in the signals collected from the two microphones is further tested; the update of the adaptive filter coefficient is controlled based on the test result; and lastly, based on a controlled adaptive filter coefficient, the obtained intensified target phonetic signals and the weakened target phonetic signals undergo an adaptive filter process. According to the invention, the performance of noise elimination is greatly improved without affecting the quality of the target phonetics even in case that the microphones are not increased in number.

This includes systems and methods for noise cancellation and power management in a wireless headset. The wireless headset can perform noise cancellation by using two or more omni-directional microphones to generate a noise canceling “cone.” Audio signals received outside of the cone can be filtered out. An accelerometer can be used to determine the location of the wireless headset and the system can then properly position the cone to face the user's voice and filter out other audio signals. Additionally, by monitoring the ambient noise, the system can save power by turning off the noise cancellation system when the amount of ambient noise is below a threshold value.

An active cancellation unit is disclosed for improving the noise cancellation between a transmitter and a receiver which are connected to an antenna using a duplexer, the unit comprising a coupler sampling a signal to transmit provided by the transmitter, a cancellation duplexer having characteristics similar to the duplexer and receiving the sampled signal to provide a simulated signal and an active component receiving the simulated signal and providing an amplified signal having a phase 180 degree shifted with respect to the simulated signal; and a coupler for injecting the simulated signal at the receiver.

This includes systems and methods for noise cancellation and power management in a wireless headset. The wireless headset can perform noise cancellation by using two or more omni-directional microphones to generate a noise canceling “cone.” Audio signals received outside of the cone can be filtered out. An accelerometer can be used to determine the location of the wireless headset and the system can then properly position the cone to face the user's voice and filter out other audio signals. Additionally, by monitoring the ambient noise, the system can save power by turning off the noise cancellation system when the amount of ambient noise is below a threshold value.

This includes systems and methods for accelerometer usage in a wireless headset. An accelerometer can be used to determine the location of a wireless headset. The determined location can be used to control and improve a noise cancellation system. In some embodiments, the determined location can be used in controlling the functions of buttons of the wireless headset. In some embodiments, the accelerometer can further be used to determine when the system is in use. If the system has not been in use for a predetermined amount of time, at least a portion of the wireless headset can be turned off to save power.

The invention discloses a voice enhancement system and method for a cellphone microphone, and the method comprises the steps: firstly carrying out the time domain noise reduction processing of noise voice signals of a main microphone and an auxiliary microphone; secondly filtering out the linear related noises between the main microphone and the auxiliary microphone; thirdly converting the signals after time domain noise reduction to a frequency domain for frequency domain noise reduction, thereby further filtering the linear uncorrelated noises between the main microphone and the auxiliary microphone. The method determines a voice frequency point and a noise frequency point in the frequency domain through employing the reference sound of voice and a harmonic structure, adjusts the parameters of a frequency domain wiener filter for the voice and noise frequency points, retains the voice frequency point while enabling the wiener filter to precisely filter the noise frequency point, achieves the reduction of voice distortion, and improves the call quality of a cellphone.

This includes systems and methods for accelerometer usage in a wireless headset. An accelerometer can be used to determine the location of a wireless headset. The determined location can be used to control and improve a noise cancellation system. In some embodiments, the determined location can be used in controlling the functions of buttons of the wireless headset. In some embodiments, the accelerometer can further be used to determine when the system is in use. If the system has not been in use for a predetermined amount of time, at least a portion of the wireless headset can be turned off to save power.

The hearing system (1) comprises a filtering unit (6) for improving a signal-to-noise ratio of an S+N-audio signal (S+N) composed of a desired audio signal (S) and a unwanted audio signal (N), which filtering unit (6) comprisesan adaptive filter;an S+N-input for receiving said S+N-audio signal (S+N);an N*-input for receiving an N*-audio signal (N*), which is used as an estimate for said unwanted audio signal (N); andan S*-output for outputting an S*-audio signal (S*) obtained in dependence of said S+N-audio signal (S+N) and said N*-audio signal (N*), which is an approximation towards said desired signal (S);wherein the hearing system (1) comprises a selecting unit (2) operationally connected to said filtering unit (6) for selecting a first input audio signal (In1; In2; . . . ) from at least two input audio signals (In1, In2) and feeding said first input audio signal (In1; In2) either to said S+N-input or to said N*-input. Preferably, said selecting unit (2) is adapted to selecting also a second input audio signal (In2) from said at least two input audio signals (In1, In2), which is different from said first input audio signal (In1), and said first input audio signal (In1) is fed to said S+N-input, and said second input audio signal (In2) is fed to said N*-input.

The invention discloses an improved spectrum subtraction method based on a human ear masking effect and Bayesian estimation. The improved spectrum subtraction method comprises the steps of: (1) adopting an improved minimum control value recursive averaging algorithm to obtain noise power spectrum estimation of an original noisy speech; (2) combining the obtained noise power spectrum estimation forperforming preliminary spectrum subtraction on a noisy speech signal; (3) performing Bayesian estimation based on weighted likelihood ratio distortion measurement on the signal after preliminary spectrum subtraction, and calculating the optimal estimated amplitude spectrum of the signal; (4) calculating a subtraction parameter of secondary spectrum subtraction by utilizing the human ear masking effect; (5) performing IMCRA noise estimation again before secondary spectrum subtraction, and carrying out secondary spectrum subtraction to obtain a final enhanced speech signal; (6) and performing inverse Fourier transform on the enhanced speech signal to obtain a final enhanced speech. The improved spectrum subtraction method better guarantees the intelligibility of the speech while improving the noise elimination capability of the algorithm, thereby improving the overall effect of speech enhancement.

A noise canceling system comprises a microphone generating a captured signal and a sound transducer radiating a sound canceling audio signal in the audio environment. A feedback path from the microphone to the sound transducer includes a non-adaptive canceling filter and a variable gain and receives the captured signal and generates a drive signal for the sound transducer. A gain detector determines a secondary path gain for at least part of a secondary path of a feedback loop. The secondary path may include the microphone, the sound transducer, and the acoustic path therebetween but does not include the non-adaptive canceling filter or the variable gain. A gain controller adjusts the in of the variable gain in response to the secondary path gain. The system use simple gain estimation and control to efficiently compensate for variations in the secondary path to provide improved stability and noise canceling performance.

A bandpass filter circuit 10 of the present invention includes: transconductance amplifier circuits 1 to 3; a common-mode feedback circuit 4 which outputs a first control signal to the transconductance amplifier circuit 1 so that a D.C. voltage level of a differential output of the transconductance amplifier circuit 1 is at a predetermined level; a common-mode feedback circuit 5 which outputs a second control signal to the transconductance amplifier circuit 2 so that a D.C. voltage level of a differential output of the transconductance amplifier circuit 2 is at a predetermined level; and capacitors C1 to C3. Each of the members are connected as shown in FIG. 1. With the configuration, a bandpass filter circuit capable of adjusting constants such as a Q-value is realized.

An embodiment of the invention provides a voice enhancement processing method and device. The method includes: decoding bit streams, and obtaining coding parameters of a current voice subframe to be processed, the coding parameters including first generation digital book gains and first self-adaptive code book gains; adjusting the first generation digital book gains, and obtaining second generation digital book gains; determining second self-adaptive code book gains according to the first self-adaptive code book gains and the second generation digital book gains; and adopting quantization indexes of the second generation digital book gains and the second self-adaptive code book gains to replace bits corresponding to the first generation digital book gains and the first self-adaptive code book gains. By adoption of the technical scheme of the invention, an effect of eliminating noise can be effectively improved, and voice communication quality can be improved.

The invention provides a dust removal grinding wheel machine which belongs to the technical field of operation. The invention solves the problems of easy breakage of a cloth bag, short service life and troublesome use in the traditional dust removal grinding wheel machine. The dust removal grinding wheel machine comprises a working platform, a motor, a dust hood and a grinding wheel, wherein a fan which is positioned under a platform plate is fixed on the working platform; a cyclone dust removal mechanism which is provided with an air inlet pipe, an exhaust pipe and a dust discharging opening and can be used for separating dust from dust-contained gas and discharging the dust from the dust discharging opening is arranged between the fan and the dust hood; the air inlet pipe is communicated with the dust hood; the exhaust pipe is communicated with an air inlet of the fan; and a dust collecting mechanism which is communicated with the dust discharging opening and can ensure that the dust discharging opening is sealed and can be used for collecting dust falling off the dust discharging opening is fixed on the working platform. The dust removal grinding wheel machine has the advantages of simple structure, reasonable and compact design, low manufacture cost, good dust removal and noise reduction effect and convenient dust particle cleaning.

The invention provides a vibration and noise reduction device of a compressor. The vibration and noise reduction device of the compressor comprises a surrounding wall, a mounting cavity used for mounting the compressor is formed in the surrounding wall, the surrounding wall comprises a sealed shell, a sound absorption layer and a sound insulation layer, the sound absorption layer is arranged on the inner side of the sealed shell, the sound insulation layer is arranged between the sealed shell and the sound absorption layer, and sound wave energy decrement holes are formed in the sound insulation layer. The noise reduction function of the vibration and noise reduction device of the compressor can be improved.

A headphone or earphone is provided which includes a housing with an open end and at least one defined dominant acoustic opening, an acoustically sealing earpad arranged at the open end of the housing, and at least one microphone arranged adjacent to common ear or in the vicinity of the dominant acoustical opening for detecting noise. The dominant acoustic opening is arranged within a radius of 2 cm around a midpoint of the at least one microphone. The headphone or earphone also includes an active-noise-compensation unit for performing an active noise compensation based on the output of the microphone and for generating a compensation signal. The headphone or earphone also includes an electro-acoustical transducer inside the housing for reproducing the compensation signal.

The invention provides a noise suppression method, a device thereof, electronic equipment and a communication processing method. The noise suppression method comprises the steps of obtaining a first speech signal collected by a first terminal in a user speech collection state, obtaining at least one second speech signal collected by a second terminal in a non user speech collection state, and using the second speech signal to carry out noise elimination operation on the first speech signal and obtaining a third speech signal. According to the noise suppression method, the device thereof, the electronic equipment and the communication processing method, the noise suppression of the terminal of a single microphone can be carried out, and the noise suppression of the terminals of multiple microphones can be carried out too.

The invention is applicable to the field of noise elimination and provides a digital feed-forward adaptive hybrid active noise control method and device. The method comprises: setting a feed-forward control filter and a feedback control filter; the feed-forward control filter filtering an acquired reference signal to obtain a first control signal, and the feedback control filter filtering an acquired error signal to obtain a second control signal; the feedback control filter carrying out adaptive iteration according to the error signal acquired by an error sensor, and the feed-forward control filter carrying out adaptive iteration according to the reference signal and error signal. Through the adaptive adjustment of filter parameters and the feedback control scheme and feed-forward control scheme using a same algorithm module, system complexity is reduced.

An operational amplifier circuit includes a transconductance amplifier circuit which converts a differential input voltage into a differential output current; a common-mode feedback circuit which outputs a control signal to the transconductance amplifier circuit 1 so as to make a D.C. voltage level of a differential output voltage of the transconductance amplifier circuit equal to a reference voltage; a voltage supply circuit which supplies a reference voltage to the common-mode feedback circuit; and an output load to which the differential output voltage of transconductance amplifier circuit is applied, and which constitutes an output terminal of the operational amplifier circuit 5. A power source voltage is supplied to each of the circuits. The operational amplifier circuit has an improved power-source noise canceling characteristic while maintaining its dynamic range.

A system and method for sending high fidelity sound between wireless units include the capability to receive audible sounds at a wireless unit and generate signals that represent the audible sounds. The system and method also include the capability to encode a first portion of the signals and encode a second portion of the signals. The system and method further include the capability to transmit the first encoded portion over a first synchronous channel and transmit the second encoded portion over a second synchronous channel.

An operational amplifier circuit 5 of the present invention includes: a transconductance amplifier circuit 1 which converts a differential input voltage into a differential output current; a common-mode feedback circuit 2 which outputs a control signal to the transconductance amplifier circuit 1 so as to make a D.C. voltage level of a differential output voltage of the transconductance amplifier circuit 1 equal to a reference voltage vref; a voltage supply circuit 3 which supplies, as the reference voltage vref, a voltage which is hardly affected by a power source voltage to the common-mode feedback circuit 2; and an output load ZL to which the differential output voltage of transconductance amplifier circuit 1 is applied, and which constitutes an output terminal of the operational amplifier circuit 5. To each of the circuits, a power source voltage vdd is supplied from a power source terminal. With the operational amplifier circuit 5 having the above configuration, it is possible to realize an operational amplifier circuit whose power-source noise canceling characteristic is improved while its dynamic range is kept from decreasing.

A MEMS transducer (10) for an audio device comprises a substrate (12), a membrane (14) attached to the substrate (12), and a back-electrode (18) attached to the substrate (12), wherein a resonant frequency of the back-electrode (18) is matched to a resonant frequency of the membrane (14). Further, a method of manufacturing a MEMS transducer (19) for an audio device comprises attaching a membrane to a substrate (12), attaching a back-electrode (18) to the substrate (12), matching a resonant frequency of the back-electrode (18) to a resonant frequency of the membrane (14).

A fan shroud includes a fan shroud portion having a surface including an aperture. A cooling fan is supported proximate to the aperture for permitting air flow through the fan shroud from the environment to the engine compartment. An air intake portion is supported on the fan shroud portion. The air intake portion and the fan shroud portion together define at least a portion of an air passageway having an inlet for receiving ambient air and an outlet for connection to an engine throttle. The fan shroud portion and air intake portion may respectively include first and second circumferential portions that define the air passageway.

The present invention discloses an electrical stimulation noise elimination instrument, which includes two microelectrodes used for collecting bioelectric signals. The signal output ends of the microelectrodes are output via a noise suppression circuit. The noise suppression circuit includes a differential amplification circuit and a resistance and capacity compensating circuit. The electric signals collected by the microelectrodes are respectively input into the two input ends of the differential amplification circuit via the resistance and capacity compensating circuit. With the electrical stimulation noise (artifact) elimination instrument of the present invention, the electrical stimulation noises which are more than forty times larger than the bioelectric signals can be eliminated. Therefore, the present invention is beneficial to the organic combination of two nerves electrical physiology study techniques of the electrical stimulation and the unit discharging records, which takes a positive promotion effect on the study of the nerves electrical physiology.

Noise abatement within a signal stream containing unwanted signal referred to as noise is performed by acquiring a digitized noise signal and using a digital processor circuit to subdivide the acquired noise signal into different frequency band segments and thereby generate a plurality of segmented noise signals. Then individually for each segmented noise signal, the processor shifts in time the segmented noise signal by an amount dependent on a selected frequency of the segmented noise signal to produce a plurality of shifted segmented noise signals. The precise time shift applied to each noise segment considers the frequency content of the segment and the system processing time. Individually for each segmented noise signal, amplitude scaling is applied. The shifted and amplitude-scaled segmented noise signals are then combined to form a composite anti-noise signal which is output into the signal stream to abate the noise through destructive interference.

The invention provides a grinding machine with a dust removal function, belonging to the technical field of operation. The grinding machine with the dust removal function solves the problems that a cloth bag in the existing grinding machine with the dust removal function is apt to rupture, the service life is short and the existing grinding machine with the dust removal function is troublesome to use. The grinding machine with the dust removal function comprises a worktable, a motor, a dust suction hood and a grinding wheel. A fan below a table board is fixedly arranged on the worktable. An air inlet pipe, an air exhaust pipe, a dust discharge port and a cyclone dust removal mechanism which can separate out dust in dust-containing air and discharge the dust from the dust discharge port are arranged between the fan and the dust suction hood. The air inlet pipe is communicated with the dust suction hood. The air exhaust pipe is communicated with the air inlet of the fan. A dust collection mechanism which is communicated with the dust discharge port, can enable the dust discharge port to be closed and can collect the dust which falls down from the dust discharge port is fixedly arranged on the worktable. The grinding machine with the dust removal function has the advantages of simple structure, reasonable and compact design, low manufacturing cost, good dust removal and noise reduction effect and convenience in dust particle cleaning.