Echo Path Gain Control for Double-Talk Voice Quality
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Solution Overview
Problem
Existing echo cancellation technologies face challenges in achieving full duplex voice communication with sufficient echo cancellation, especially on highly non-linear platforms, leading to resource-intensive processing and degradation of the near-end signal during double talk.
Innovation Solution
A gain control system that detects echoes and near-end signals to adjust the gain applied to the far-end signal based on the estimated characteristics of the echo path, including non-linearity and delay variations, to optimize the quality of the near-end signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adaptive signal processing is used to generate accurate echo cancellation, then echo cancellation performance is improved, but processing becomes resource intensive and causes degradation of near-end signal during double talk
Solution Approach 1:
The gain controller dynamically adjusts the gain applied to the far-end signal based on detected echo path characteristics such as non-linearity and delay variations. This dynamic adaptation allows the system to optimize echo cancellation performance while reducing processing resources during double talk by lowering the gain when echo path conditions indicate potential signal degradation.
Solution Approach 2:
The system uses feedback from the echo path estimator to continuously monitor echo path characteristics and adjust the gain controller accordingly. The feedback mechanism enables the system to respond to changing acoustic conditions and optimize the balance between echo cancellation effectiveness and near-end signal quality preservation.
2Reliability
If gain is increased to improve far-end signal quality, then far-end signal quality is improved, but echo cancellation errors increase during double talk
Solution Approach 1:
The gain controller dynamically adjusts the gain applied to the far-end signal based on detected echo path characteristics such as non-linearity and delay variations. This dynamic adaptation allows the system to optimize echo cancellation performance while reducing processing resources during double talk by lowering the gain when echo path conditions indicate potential signal degradation.
Solution Approach 2:
The system changes the gain parameter based on detected echo path characteristics including non-linearity and delay variations. By adjusting this critical parameter in response to echo path conditions, the system optimizes the balance between far-end signal quality and near-end signal preservation during double talk.
3Reliability
If processing is intensified to cancel echoes in highly non-linear platforms, then echo cancellation capability is improved, but near-end signal degradation increases during double talk
Solution Approach 1:
The system performs preliminary estimation of echo path characteristics including non-linearity and delay variations before double talk occurs. This preliminary action allows the gain controller to be pre-configured with appropriate gain values that will prevent near-end signal degradation when double talk is detected, rather than reacting after degradation has occurred.
Solution Approach 2:
The gain controller dynamically adjusts the gain applied to the far-end signal based on detected echo path characteristics such as non-linearity and delay variations. This dynamic adaptation allows the system to optimize echo cancellation performance while reducing processing resources during double talk by lowering the gain when echo path conditions indicate potential signal degradation.
Data Source
AI summary
A gain control system for applying gain to a far-end signal, the system comprising: a signal identifier configured to detect an echo of the far-end signal in a microphone signal; and a path estimator configured to estimate a characteristic of an echo path of the detected echo, wherein: the signal identifier is further configured to detect a near-end signal from the microphone signal; and in response to detecting the near-end signal, the gain control system is configured to adjust the gain applied to the far-end signal in dependence on the estimated characteristic of the echo path.