Acoustic Echo Cancellation Without Shared Clock
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Solution Overview
Problem
Existing acoustic echo cancellation (AEC) techniques require a common word clock between playback and microphone devices, which can lead to timing drift and render AEC ineffective when a shared clock is not possible or practical, especially in environments like smart devices and video conferencing systems.
Innovation Solution
The implementation of semi-blind source separation methods that use a representation of the acoustic TV audio signal to guide the separation of speech from the user, without relying on a well-defined synchronization between the playback and microphone devices, allowing for effective echo cancellation even without a shared clock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional AEC techniques use adaptive filters with common word clock synchronization, then echo cancellation effectiveness is improved, but device complexity and timing drift issues worsen when shared clock is not available
Solution Approach 1:
The patent extracts the synchronization requirement from the AEC system by using blind source separation that does not depend on common word clock. The system separates the reference signal from the mixed signal through statistical independence assumptions rather than temporal synchronization, removing the clock sharing constraint while maintaining echo cancellation effectiveness
Solution Approach 2:
The patent introduces an intermediary reference signal that is a function of the loudspeaker input signal but does not require direct clock synchronization. This intermediary representation allows the AEC system to operate without shared clock while still providing the necessary reference for echo prediction and cancellation
2Measurement precision
If AEC systems require common word clock between playback and microphone devices, then timing alignment is improved, but adaptability worsens when shared clock is not practical
Solution Approach 1:
The patent implements dynamic adaptation by using blind source separation algorithms that can handle variable timing relationships between signals. The system dynamically adjusts to timing drift through statistical signal processing rather than rigid clock synchronization, enabling operation in environments where shared clock is not practical
Solution Approach 2:
The patent changes the fundamental parameter from temporal synchronization (common word clock) to statistical independence (blind source separation). This parameter transformation allows the system to maintain timing alignment through statistical relationships rather than clock synchronization, greatly improving adaptability to different operating conditions
3Measurement precision
If AEC uses precise clock synchronization, then source separation accuracy is improved, but device complexity and synchronization infrastructure requirements worsen
Solution Approach 1:
The patent extracts the synchronization infrastructure requirement from the system by implementing blind source separation that operates on statistical properties of signals rather than temporal alignment. This eliminates the need for complex clock synchronization infrastructure while maintaining source separation accuracy through mathematical relationships between signals
Data Source
AI summary
A method of capturing speech using a television system comprising a microphone device and a playback device. A playback device of the television system plays a tv audio signal to generate acoustic tv audio and a microphone of the television system captures a speech audio signal comprising a mixture of speech from a user and the acoustic tv audio. The method obtains a representation of the tv audio signal that lacks a well-defined synchronization with the tv audio signal and processes the speech audio signal using a semi-blind source separation process to separate the speech from the user from the acoustic tv audio.