Entity

Time filter

Source Type

Newport Beach, CA, United States

Patent
Conexant Systems Inc. | Date: 2014-02-25

A level shifter comprising a first driver transistor for receiving an input signal. A gate-controlled transistor coupled to the first driver transistor. A second driver transistor coupled to the gate controlled transistor. An output coupled to the second driver transistor, wherein the gate-controlled transistor is for receiving a predetermined gate voltage when the output voltage exceeds a predetermined value.


Patent
Conexant Systems Inc. | Date: 2014-03-04

A system for audio processing comprising an initial background statistical model system configured to generate an initial background statistical model using a predetermined sample size of audio data. A parameter computation system configured to generate parametric data for the audio data including cepstral and energy parameters. A background statistics computation system configured to generate preliminary background statistics for determining whether speech has been detected. A first speech detection system configured to determine whether speech was present in the initial sample of audio data. An adaptive background statistical model system configured to provide an adaptive background statistical model for use in continuous processing of audio data for speech detection. A parameter computation system configured to calculate cepstral parameters, energy parameters and other suitable parameters for speech detection. A speech/non-speech classification system configured to classify individual frames as speech frames or non-speech frames, based on the computed parameters and the adaptive background statistical model data. A background statistics update system configured to update the background statistical model based on detected speech and non-speech frames. A second speech detection system configured to perform speech detection processing and to generate a suitable indicator for use in processing audio data that is determined to include speech signals.


A method for echo cancellation in multichannel audio signals includes receiving a plurality of time-domain signals, including multichannel audio signals and at least one reference signal, transforming the time-domain signals to K under-sampled complex-valued subband signals using an analysis filter bank, and performing, for each of the K under-sampled complex-value subband signals, linear echo cancellation of the reference signal from each channel using an acoustic echo canceller. A probability of acoustic echo dominance is produced using a single-double talk estimator, and a semi-blind multichannel source separation is performed based on the probability and independent component analysis (ICA) to decompose the audio signals into a near-end source signal and a residual echoes using subband semi-blind source separation. The residual echo components are removed from the near-end source signal using a spectral filter bank, and the subband audio signals are reconstructed to a multichannel time-domain audio signal using a subband synthesis filter.


A system for processing audio data comprising a linear demixing system configured to receive a plurality of sub-band audio channels and to generate an audio output and a noise output. A spatial likelihood system coupled to the linear demixing system, the spatial likelihood system configured to receive the audio output and the noise output and to generate a spatial likelihood function. A sequential Gaussian mixture model system coupled to the spatial likelihood system, the sequential Gaussian mixture model system configured to generate a plurality of model parameters. A Bayesian probability estimator system configured to receive the plurality of model parameters and a speech/noise presence probability and to generate a noise power spectral density and spectral gains. A spectral filtering system configured to receive the spectral gains and to apply the spectral gains to noisy input mixtures.


Patent
Conexant Systems Inc. | Date: 2014-03-04

A circuit comprising a peak detector configured to receive a positive voltage input, a negative voltage input and a reference current source input and to output a peak signal data value. A fast attack current source control coupled to the peak detector and configured to generate a current source control signal as a function of the peak signal data value. A slow decay control coupled to the fast attack current source control and configured to reduce the current source control signal based on a predetermined or user-selected decay rate. A variable current source coupled to the fast attack current source control and configured to generate a variable current as a function of the current source control signal. Amplifier circuitry coupled to the variable current source, the amplifier circuitry configured to receive the variable current.

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