110results 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.

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.

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.

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 method and apparatus for detecting quadrupole nuclei in motion relative to a search region, during the sensing operation, provides a system for decreasing the throughput time of quadrupole resonance (QR) detection systems. The apparatus uses a single QR probe, or a plurality of QR probes, which may be formed into an array, to remotely and non-invasively generate a QR response from one or more targets containing quadrupole nuclei, as they pass through the probe-sensing region. The method employs an optimized pulse sequence that simultaneously increases the QR signal power while reducing the peak power of the RF pulses. The pulse sequence generates a matrix of signals that are processed to improve detection performance by increasing the signal to noise ratio.

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.

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.

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.