Conexant Systems, Inc.

Synaptics Corporation

Mouna Elkhatib

Christian Larsen

Lorenzo Crespi

James Walter Wihardja

Jonathan Chien

Trausti Thormundsson

Yair Kerner

James Bunde Villadsen Skov

Jimmy Pu

Mary Xiao-Hua Lu

Mary X Lu

James Bunde Viliadsen Skov

A system for processing audio data comprising an amplifier configured to receive an audio signal and to perform nonlinear processing on the audio signal. An encoder coupled to the amplifier, the encoder configured to receive the nonlinearly processed audio signal and to encode the nonlinearly processed audio signal into a data transmission format. A transmitter configured to receive and transmit the encoded nonlinearly processed audio signal. A receiver configured to receive the transmitted encoded nonlinearly processed audio signal and to decode the encoded nonlinearly processed audio signal. A digital voice processor configured to receive the nonlinearly processed audio signal and to use the nonlinearly processed audio signal for echo estimation and to subsequently subtract the estimated echo signal from a microphone signal.

Class-D amplifier with pulse density modulation output feedback for higher performance acoustic echo canceller

A driver controller comprising a state machine for controlling transitions between a plurality of states. An output switch for providing a low impedance path to ground during transition periods. An output stage for decoupling output signal from driver amplifier during the transition periods.

Power management controller for drivers

Audio transducers (headphones, speakers, microphones) inherently do not accurately reproduce the signal presented to them at the input. This can be compensated for by taking into account the transducer characteristics and transforming the input signal using a digital signal processor (DSP) to counteract the inaccuracies. However, for the compensation to take place, the DSP needs to know the characteristics of the transducer. For systems with built-in transducers (like laptops with internal speakers) the characteristics of the internal speakers can be stored on the hard-drive of the laptop and the DSP can read this data and make the appropriate compensations. Because a transducer (headphone, speaker, microphone) has its own characteristics that need to be compensated for separately, a profile is supplied to the DSP either by a database lookup based on an identification made by the user or transducer itself or by profile information stored on the transducer. Once the characteristics of a transducer are known, many additional DSP algorithms can be applied in order to improve the audio performance and even safety of the system.

Systems and methods for transducer calibration and tuning

Biphase mark codes (BMC) are used in digital communications. Most BMC formats use preambles for rate determination and synchronization. A decoder compares the intervals of continuous high or continuous low voltages in a BMC stream to predetermined minimum and maximum values of half cell, full cell and one-and-a-half cell intervals for all supported sampling rates. If a pattern matching a preamble is found, the sampling rate is locked in and the decoder is synchronized to the BMC stream. Once locked, the decoder uses the predetermined minimum and maximum values at the locked rate to generate half cell, full cell and one-and-a-half cell indicators for a decoding state machine which decodes data in the BMC stream or decodes expected preambles.

Biphase mark code decoder and method of operation

Challenges to the implementation of equalization in the 2.1 environment arise from the constraints imposed by HD audio requirements and Windows&#xae; Vista&#x2122;. A hybrid software hardware solution overcomes many of the challenges by exploiting the software capability for equalization and using a hardware codec to perform the separation into high frequency and low frequency audio streams needed to drive stereo speakers and a subwoofer.

2.1 crossover equalization in PC audio applications

An integrated audio codec includes a high-pass filter to prevent damage to personal computer speakers and other components. The audio codec may be compliant with HD audio standards and can operate with generic software drivers. Tuning of the high-pass filter is provided through an external pin-out where either an external capacitor or external resistors provide an ability to tune the high-pass filter. In one implementation, a tuning voltage is digitized into a tuning code used by a digital high-pass filter. In addition, multiplexers can be used to insure only the audio path leading to the speakers is filtered.

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Tustin, CA, United States of America

Mouna Elkhatib