Echo Cancellation via Volume Control to Prevent Microphone Clipping

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Solution Overview

Problem

Current smart TV speech recognition systems experience low speech recognition rates due to clipping distortion in microphone signals at high volumes, leading to poor echo cancellation and user experience.

Innovation Solution

The method involves presetting a maximum amplitude value for microphone signals and adjusting the TV volume in real-time to prevent clipping distortion, ensuring stable echo cancellation by maintaining the self-adapting filter's coefficients in a stable state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the TV volume is increased to improve audio output, then the sound quality is improved, but the microphone signal experiences clipping distortion which degrades echo cancellation performance

Engineering Contradiction:
Improveaudio output volumeVSAvoidecho cancellation performance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The system performs preliminary detection of clipping distortion in the microphone signal before echo cancellation processing. When clipping is detected, the system proactively adjusts the TV volume down to prevent further distortion, thereby maintaining reliable echo cancellation performance while preserving audio output quality

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where the echo cancellation performance is continuously monitored by detecting clipping distortion in the microphone signal. Based on this feedback, the TV volume is automatically adjusted to prevent clipping, creating a closed-loop control system that maintains both audio quality and echo cancellation reliability

Inventive Principle:
Principle #23Feedback

2Reliability

If the TV volume is turned down to avoid clipping distortion, then the echo cancellation performance is improved, but the audio output volume is reduced

Engineering Contradiction:
Improveecho cancellation performanceVSAvoidaudio output volume
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The system employs periodic detection of clipping distortion in the microphone signal at predetermined intervals. This periodic monitoring allows the system to maintain high audio output volume during normal operation while periodically checking for and correcting clipping conditions, thus achieving both high audio quality and reliable echo cancellation

Inventive Principle:
Principle #19Periodic action

3Adaptability or versatility

If the self-adapting filter is allowed to reconverge after clipping distortion, then the echo cancellation can adapt to new conditions, but the convergence process takes time during which echo cancellation performance remains poor

Engineering Contradiction:
Improveecho cancellation adaptationVSAvoidconvergence time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system applies preliminary anti-action by detecting clipping distortion before it severely degrades echo cancellation performance. By identifying the clipping condition early and immediately adjusting the TV volume, the system prevents the need for lengthy reconvergence of the self-adapting filter, thus maintaining both adaptability and minimizing performance loss time

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP3734600B1Method, system and storage medium for solving echo cancellation failure
Publication Date: 2025.06.04 SHENZHEN TCL NEW-TECH CO LTD
  • EP3734600B1 patent drawingFigure 1
  • EP3734600B1 patent drawingFigure 2~3
  • EP3734600B1 patent drawingFigure 4~5

AI summary

A method, system and storage medium for solving echo cancellation failure; method comprises: starting echo cancellation algorithm for convergence of self-adapting filter to stabilize coefficient of filter function (S100); presetting maximum amplitude value for signal intensity that microphone can receive, and detecting if microphone signal lower than maximum amplitude value (S200); prompting user or television system automatically to turn down television volume when microphone received signal larger than or equal to maximum amplitude value, to ensure microphone received signal intensity lower than maximum amplitude value (S300); echo cancellation being carried out without distortion of signals, wherein coefficient of self-adapting filter function W(n) may be continually kept stable, avoiding self-adapting filter converging multiple times due to signal distortion (S400). Method effectively solves problem of echo cancellation of self-adapting filter failing caused by multiple convergences due to clipping distortion of microphone signal.