Conexant Systems, Inc.

Synaptics Corporation

James Walter Wihardja

Trausti Thormundsson

Ragnar Hlynur Jonsson

Harry K Lau

Yair Kerner

Jonathan Chien

Shlomi I Regev

Govind Kannan

Vilhjalmur S Thorvaldsson

Mouna Elkhatib

Christian Larsen

Xiaoyan Vivian Qian

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

An audio driver with reduced rub and buzz distortion that includes a digital processing module. A digital to audio converter (DAC) operable to receive a digital audio signal supplied by the digital processing module. One or more analog driver stages operable to receive an analog audio signal supplied by the DAC. A peak amplitude compressor.

System and method for reducing rub and buzz distortion

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.

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

A sound reproduction apparatus comprising a loudspeaker bar having a plurality of loudspeakers. A loudspeaker bar controller coupled to the loudspeaker bar for processing audio data for the plurality of loudspeakers, the loudspeaker bar controller comprising a spatial enhancement/virtualization system for receiving a surround channel of audio data and processing the surround channel of audio data with a spatial generation/virtualization filter, wherein a left stereo channel of audio data and a right stereo channel of audio data are not processed with the head related transfer function filter. Bass is enhanced for small speakers which are not able to produce bass frequencies.

Systems and methods for speaker bar sound enhancement

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

There is provided a method for use in a computer for redirecting an audio stream from a first audio endpoint to a second audio endpoint in the computer having a controller and a computer operating system for execution by the controller. The method includes directing the audio stream from a client application running on the computer operating system through a first audio resource stack of the computer to the first audio endpoint. The method further includes creating an audio endpoint bridge using the computer operating system, where the audio endpoint bridge provides a path for the audio stream to be directed from the first audio resource stack to pass through a second audio resource stack to the second audio endpoint. The method may also enhance the audio stream to reduce noise and redirect the audio stream to the second audio endpoint using the audio endpoint bridge.

Method and system for removal of clicks and noise in a redirected audio stream

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.

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Fullerton, CA, United States of America

James Walter Wihardja