Adaptive Propagation Delay Estimation for Audio Echo Cancellation
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Solution Overview
Problem
Propagation delay in audio communication systems can significantly hinder the effectiveness of acoustic echo cancellers, especially when the microphone position changes, leading to reduced echo cancellation performance and inhibited speech recognition.
Innovation Solution
Adaptive estimation of propagation delay by measuring echo return loss enhancement using different propagation delay parameters and selecting the parameter corresponding to the maximum echo return loss enhancement, allowing continuous updating and recalculating to adapt to changes in the environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the microphone is moved to capture audio signals, then the adaptability of the system is improved, but the propagation delay changes causing deterioration of echo cancellation performance
Solution Approach 1:
The system dynamically adapts to changing propagation delay by continuously monitoring echo return loss enhancement and adjusting the propagation delay parameter in real-time. This allows the echo canceller to maintain optimal performance despite microphone movement, transforming a static system into a dynamic one that responds to environmental changes.
Solution Approach 2:
The system employs feedback mechanisms by measuring echo return loss enhancement and using this measurement to adjust the propagation delay parameter. This closed-loop feedback ensures that the system automatically corrects for propagation delay changes caused by microphone movement, maintaining reliable echo cancellation performance.
2Device complexity
If the propagation delay parameter is fixed, then the device complexity is reduced, but the echo cancellation performance deteriorates when environment changes
Solution Approach 1:
The system performs self-adjustment by automatically detecting propagation delay changes through echo return loss enhancement measurement and updating its own propagation delay parameter without external intervention. This self-service capability maintains high reliability while adding minimal complexity, as the system uses its existing echo cancellation infrastructure for parameter adaptation.
Solution Approach 2:
The system changes the propagation delay parameter based on measured echo return loss enhancement to adapt to environmental changes. By dynamically adjusting this critical parameter, the system maintains optimal echo cancellation performance across varying conditions without requiring complete system redesign.
3Speed
If the propagation delay is not aligned, then the processing speed is improved, but the speech recognition accuracy deteriorates
Solution Approach 1:
The system performs preliminary alignment of playback and microphone signals by measuring echo return loss enhancement and adjusting the propagation delay parameter before speech recognition processing. This preliminary action ensures that signals are properly synchronized, improving speech recognition accuracy without significantly impacting overall processing speed.
Data Source
AI summary
Features are disclosed for adaptively estimating propagation delay in an audio system. A first device in communication with a speaker may be configured produce sound based on an audio playback signal. A second device in communication with one or more microphones may be configured to detect sound as a microphone signal. The second device may perform acoustic echo cancellation using a first propagation delay parameter and determine a first echo return loss enhancement. The second device may perform acoustic echo cancellation using a second propagation delay parameter and determine a second echo return loss enhancement. A propagation delay between the audio playback signal and the microphone signal may be adaptively estimated based on a comparison of the first and second echo return loss enhancements.