Conexant Systems, Inc.

Mindspeed Technologies, Inc.

Synaptics Corporation

Sarnoff Corporation

Ragnar Hlynur Jonsson

Trausti Thormundsson

Sverrir Olafsson

William W Jones

Vilhjalmur S Thorvaldsson

Govind Kannan

Keith R Jones

Harry K Lau

James Walter Wihardja

Yair Kerner

Youhong Lu

Derek T Walton

Elias Bjarnason

Shlomi I Regev

Gilberto Isaac Sada Treviño

Robert Norman Hurst

Ali Abdollahzadeh Milani

Maurice M Reintjes

Shrenik P Patravali

David Andrew Birks

Gilberto Isaac Sada Trevi&ntilde;o

Adeline Tracz

Sveinn V Grimsson

An active noise cancellation system includes a sensor operable to sense environmental noise and generate a corresponding reference signal, a fixed noise cancellation filter including a predetermined model of the active noise cancellation system operable to generate an anti-noise signal, and a tunable noise cancellation filter operable to modify the anti-noise signal in accordance with stored coefficients, wherein the tunable noise cancellation filter is further operable to modify the stored coefficients in real-time based on user feedback and generate a tuned anti-noise signal that models tunable deviations from the predetermined noise model. A graphical user interface is operable to receive user adjustments of tunable parameters in real-time, the tunable parameters corresponding to at least one of the stored coefficients.

Methods and systems for end-user tuning of an active noise cancelling audio device

An audio driver equipped with a distortion compensation unit corrects for detected distortion and includes a digital to analog converter (DAC), an amplifier, and an output driver that drives a loudspeaker. Between the output driver and the loudspeaker, the audio driver can include a series resistor and a differential amplifier to measure the voltage across the resistor. A distortion detection unit can use the detected voltage to determine whether distortion, such as rub and buzz distortion is present. The distortion detection unit can comprise an analog to digital converter (ADC) to digitize the voltage data, an FFT to transform the voltage data into frequency information, a root-mean-square (RMS) module that measures the energy at each frequency, and an analysis module which looks for the distortion signature in the energy spectrum.

Audio driver system and method

A system for controlling distortion comprising a total harmonic distortion (THD) modeling system configured to apply a chirp signal to a system and to identify one or more frequency bands at which distortion is present, and to apply a ramping signal to identify for each of the one or more frequency bands an input signal level at which distortion is initiated. A signal processing system configured to receive an input signal, to determine whether frequency components are present in the input signal that are associated with the one or more frequency bands at which distortion is present, and to limit the amplitude of the input signal at the one or more frequency bands, such as by applying dynamic range compensation.

System and method for dynamic range compensation of distortion

A system for detecting motion comprising a first speaker, a first microphone separated from the first speaker by a distance D, a sound generator, an echo parameter measurement device and an echo parameter monitor, wherein the echo parameter monitor stores two or more sequential echo parameters and generates a motion indicator if the two or more sequential echo parameters indicate a change in an acoustic echo path that exceeds a predetermined threshold.

Integrated motion detection using changes in acoustic echo path

Traditionally, echo cancellation has employed linear adaptive filters to cancel echoes in a two way communication system. The rate of adaptation is often dynamic and varies over time. Disclosed are novel rates of adaptation that perform well in the presence of background noise, during double talk and with echo path changes. Additionally, the echo or residual echo can further be suppressed with non-linear processing performed using joint frequency-time domain processing.

Systems and methods for echo cancellation and echo suppression

Acoustic echoes in communications systems are distracting and undesirable. Acoustic echoes occur in communications systems where sound produced by a speaker is picked up by a microphone in a communications system. In a stereo playback environment, echo cancellation techniques become more complicated. Echo cancellation can be performed by performing echo cancellation on a center signal, which is the sum of a left channel signal and the right channel signal, or left signal and a difference signal, which is the difference of the right channel signal and the left channel signal. The adaptation rates of the two echo cancellers meet certain constraints to prevent degeneracies in the echo cancellation system.

Systems and methods for stereo echo cancellation

An audio driver comprising a distortion detection unit coupled between an amplifier and a loudspeaker and configured to detect a distortion signal generated by the loudspeaker while the loudspeaker is being used to deliver an audio signal from the amplifier. A distortion compensation unit configured to compensate for the distortion signal without interfering with the audio signal.

An apparatus for abstract memory addressing. A processor for generating an abstract memory address. A base register for storing a base memory address. An adder for adding the base memory address to the abstract memory address and generating a physical address for a device memory. A pointer register for storing the physical address, wherein the pointer register is directly coupled to the device memory.

Apparatus and method for abstract memory addressing

A system and apparatus for constructing a displacement model across a frequency range for a loudspeaker is disclosed. The resultant displacement model is centered around the distortion point. Once a distortion model is constructed it can be incorporated into an audio driver to prevent distortion by incorporating the model and a distortion compensation unit with a conventional audio driver. Various topologies can be used to incorporate a distortion model and distortion compensation unit into an audio driver. Furthermore, a wide variety of distortion compensation techniques can be employed to avoid distortion in such an audio driver.

Peak reduction and power limitations are used to prevent distortion and protect components. In a cellular telephone, peak reduction can be based on battery power level to prevent electrical distortion from saturation. In addition peak reduction can be used to prevent mechanical distortion such as rub and buzz. Dynamic range compression can be used for peak reduction. In another application dynamic range compression can be used to control the power output to protect a speaker from damage. One example of a dynamic range compressor/peak limiter comprises a look-ahead buffer and an analysis engine. For example, the look-ahead buffer holds a window of samples of a signal. The analysis engine selects a gain envelope function on the basis of the samples, for example, by selecting the Pth sample in the buffer whenever that sample exceeds a given threshold.

Waveform shaping system to prevent electrical and mechanical saturation in loud speakers

Poly-phase filters are used to offer an efficient and low complexity solution to rate conversion. However, they suffer from inflexibility and are not easily reconfigured. A novel design for rate converters employ poly-phase filters but utilize interpolation between filter coefficients to add flexibility to rate conversion. This interpolation can be implemented as an interpolation of the poly-phase filter results. Additional approximations can be made to further reduce the amount of calculations required to implement a flexible rate converter.

Systems and methods for variable rate conversion

A system for halftone processing is provided. The system includes a programmable halftone segmentation system having one or more programmable parameters to accommodate different input image parameters, such as different printer or scanner parameters, and configured to generate output control data as a function of image input data. A programmable output processor receives the output control data and the image input data and generates image output data that compensates for halftone regions in the image input data.

Method and system for automatically detecting and processing halftone regions in scanned documents

In many audio playback systems, frequencies below a given cut off frequency are suppressed either due to speaker constraints or safety constraints. For example, some speakers are only capable of generating signals above a certain frequency. Prolonged low frequency sound can cause damage to speakers or other components. An audio driver can be equipped with a phantom bass module which by doubling, tripling and/or quadrupling frequencies below a cutoff frequency can simulate the bass experience. The doubling, tripling and quadrupling methods disclosed provide a low complexity formulation of a frequency doubling, tripling and quadrupling. In addition, the frequency doubling, tripling and quadrupling formulations are easily adapted to multi-rate processing, where computational savings can be very high.

Systems and methods for generating phantom bass

A system and method for defringing chromatic aberrations that occur in imaging devices such as scanners. The system comprises shift filters to shift lines in the various color planes together. In addition in each color plane, a spread filter is used to compensate for the unequal point spread functions of each color. Furthermore, the results can be enhanced by filtering in the luminance-chrominance space.

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Laguna Niguel, CA, United States of America

Ragnar Hlynur Jonsson