Multichannel Acoustic System Echo Cancellation

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Solution Overview

Problem

In shared acoustic spaces, such as vehicles, conversations between individuals can be hindered by echo and feedback issues due to multiple sound sources and physical limitations, making it difficult for passengers to communicate effectively.

Innovation Solution

A multichannel acoustic system comprising microphones and loudspeakers, along with a multichannel acoustic processor, is implemented to receive sound signals, filter out echo and feedback, and reproduce filtered signals, allowing clear communication between passengers in different zones of a vehicle or shared acoustic space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple microphones and loudspeakers are deployed throughout the shared acoustic space, then conversational clarity between distant passengers is improved, but echo and feedback issues worsen

Engineering Contradiction:
Improveconversational clarityVSAvoidecho and feedback
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The shared acoustic space is divided into multiple zones, each with its own microphones and loudspeakers. This segmentation allows the system to process and manage audio signals from different spatial regions independently, improving conversational clarity while enabling targeted echo and feedback cancellation for each zone rather than treating the entire space as a single unit.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system employs feedback filtering through adaptable sound filters that continuously monitor and cancel echo and feedback signals generated by the loudspeakers. The microphones detect these harmful signals, and the processing system generates counter-signals to actively cancel them, allowing the deployment of multiple loudspeakers without suffering from uncontrolled echo and feedback.

Inventive Principle:
Principle #23Feedback

2Reliability

If adaptable sound filters are used to cancel echo and feedback signals, then communication quality is improved, but system complexity increases

Engineering Contradiction:
Improvecommunication qualityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The adaptable sound filters are designed to perform multiple functions: they cancel echo signals, cancel feedback signals, and enhance conversational clarity simultaneously. This multi-functionality reduces the need for separate dedicated components for each function, thereby improving communication quality while limiting the increase in overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses adaptable sound filters whose parameters can be dynamically adjusted based on the acoustic environment and zone configuration. This adaptability allows the filters to optimize their performance for different scenarios (different passenger configurations, different noise levels) without requiring completely different filter designs, thus improving reliability while managing complexity through parameter adjustment rather than structural changes.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system enhances conversational clarity by canceling echo and feedback signals, enabling effective communication between passengers in different zones, even in noisy environments like vehicles, by using adaptable sound filters and directional microphones to improve sound quality.

Implementation Method 1

echo filtering, at a plurality of adaptable sound filters, the sound signals to cancel at least one echo signal

Methodology Applied
Scientific EffectEcho cancellation: Echo

Implementation Method 2

feedback filtering, at the plurality of adaptable sound filters, the sound signals to cancel at least one feedback signal

Methodology Applied
Scientific EffectFeedback cancellation: Feedback

Data Source

PatentEP3231166B1Enhanced conversational communications in shared acoustic space
Publication Date: 2019.12.11 QUALCOMM INC
  • EP3231166B1 patent drawingFigure 1
  • EP3231166B1 patent drawingFigure 2
  • EP3231166B1 patent drawingFigure 3

AI summary

A multichannel acoustic system (MAS) comprises an arrangement of microphones and loudspeakers and a multichannel acoustic processor (MAP) to together enhance conversational speech between two or more persons in a shared acoustic space such as an automobile. The enhancements are achieved by receiving sound signals substantially originating from relatively near sound sources; filtering the sound signals to cancel at least one echo signal detected for at least one microphone from among the plurality of microphones; filtering the sound signals received by the plurality of microphones to cancel at least one feedback signal detected for at least one microphone from among the plurality of microphones; and reproducing the filtered sound signals for each microphone from among the plurality of microphones on a subset of loudspeakers corresponding that are relatively far from the source microphone.