Adaptive Echo Cancellation for Adjacent Conference Units
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Solution Overview
Problem
Existing audio conference devices suffer from echo sounds generated between adjacent units due to speech propagation from a speaker to a microphone, which are not sufficiently removed by existing techniques.
Innovation Solution
An echo canceller system that includes a microphone signal generation unit, adaptive filter update unit, pseudo-echo signal generation unit, echo signal removing unit, target speech detection unit, and gain adjustment unit to effectively remove echoes by generating and adjusting signals based on adaptive filtering and detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple speech switching technique is used (as in Patent Literature 1), then the device complexity is low and operation is simple, but echo sounds between adjacent units cannot be sufficiently removed
Solution Approach 1:
The speech signal processing is segmented into multiple distinct functional modules: microphone signal generation, adaptive filter update, pseudo-echo signal generation, echo signal removal, target speech detection, gain adjustment, and output signal generation. Each module handles a specific aspect of echo cancellation, allowing the complex echo removal task to be divided into manageable, specialized components that work together systematically
Solution Approach 2:
A pseudo-echo signal is generated as an intermediary representation of the actual echo. This pseudo-echo signal serves as a mediator that approximates the true echo characteristics without requiring direct measurement of the echo path. The adaptive filter continuously updates to improve this intermediary representation, enabling effective echo removal through signal subtraction while maintaining system adaptability to changing acoustic environments
2Reliability
If adaptive filtering and pseudo-echo signal generation are implemented, then echo removal effectiveness is improved, but the device complexity increases
Solution Approach 1:
The adaptive filter is designed to dynamically update its coefficients in real-time based on incoming speech signals and estimated echo characteristics. This dynamic adaptation allows the system to adjust to changing acoustic conditions, speaker positions, and room acoustics automatically, maintaining high echo removal effectiveness without requiring manual reconfiguration or complex fixed-structure designs
Solution Approach 2:
The system implements feedback mechanisms where the echo-removed signal is continuously monitored by the target speech detection unit, and the adaptive filter is updated based on the difference between the actual microphone signal and the pseudo-echo signal. This feedback loop enables the system to learn from its performance and continuously improve echo cancellation effectiveness while maintaining operational simplicity through automated adjustment
Data Source
AI summary
An echo canceller generates a microphone signal, updates an adaptive filter used for estimating an echo signal, generates a pseudo-echo signal based on an output signal and the adaptive filter, removes the pseudo-echo signal from the microphone signal and generates an echo-removed signal, determines whether a target speech signal is included in the echo-removed signal, adjusts a gain of the echo-removed signal based on a determination result, and generates the output signal based on the adjusted echo-removed signal.