Low latency active noise cancellation system
AssigneeAudience, Inc.
InventorsDana Massie, Jean Laroche
Life of this patent
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Abstract
Systems and methods described herein provide for low latency active noise cancellation, which alleviates the problems associated with analog filter circuitry. The present technology utilizes low latency digital signal processing techniques that overcome the high latency conventionally associated with conversion between the analog and digital domains. As a result, low latency active noise cancellation is performed utilizing digital filter circuitry which is not subject to the inaccuracies and drift of analog filter components. In doing so, the present technology provides robust, high quality active noise cancellation.
Claims17
A method for reducing an acoustic energy level at a listening position, the method comprising:
- receiving a primary acoustic wave at a reference position to form an analog reference signal;
- converting the analog reference signal into a single-bit digital reference signal using an oversampling data converter;
- transforming the single-bit digital reference signal into a multi-bit PCM data stream;
- filtering the multi-bit PCM data stream to form a digital noise reduction signal;
- producing an analog noise reduction signal using the digital noise reduction signal;
- and
- generating a secondary acoustic wave based on the analog noise reduction signal, the secondary acoustic wave adapted to reduce the acoustic energy level at the listening position.
A system for reducing an acoustic energy level at a listening position, the system comprising:
- a reference microphone configured to receive a primary acoustic wave at the listening position;
- a noise cancellation module configured to:
- convert an analog reference signal into a single-bit digital reference signal using an oversampling data converter;
- transform the single-bit digital reference signal into a multi-bit PCM data stream;
- filter the multi-bit PCM data stream to form a digital noise reduction signal;
- produce an analog noise reduction signal using the digital noise reduction signal;
- and
- an audio transducer to generate a secondary acoustic wave based on the analog noise reduction signal, the secondary acoustic wave adapted to reduce the acoustic energy level at the listening position.
A non-transitory computer readable storage medium having embodied thereon a program, the program being executable by a processor to perform a method for reducing an acoustic energy level at a listening position, the method comprising:
- receiving a primary acoustic wave at a reference position to form an analog reference signal;
- converting the analog reference signal into a single-bit digital reference signal using an oversampling data converter;
- transforming the single-bit digital reference signal into a multi-bit PCM data stream;
- filtering the multi-bit PCM data stream to form a digital noise reduction signal;
- producing an analog noise reduction signal using the digital noise reduction signal;
- and
- generating a secondary acoustic wave based on the analog noise reduction signal, the secondary acoustic wave adapted to reduce the acoustic energy level at the listening position.
Dependencies are inferred from the claim text.