Echo Canceler Using Sound Management Signals for Voice Isolation

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Solution Overview

Problem

Audio systems, particularly in vehicles, face challenges in isolating user voice signals from microphone inputs due to the presence of echo signals generated by the system's own acoustic components, such as engine harmonics and navigation prompts, which interfere with voice processing.

Innovation Solution

The implementation of echo cancelers and residual echo suppressors that utilize sound management signals from other system components as reference signals to filter out echo components from microphone signals, employing adaptive filters and combiners to reduce echo content and enhance voice signal clarity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If sound management systems produce acoustic augmentation signals to reduce or enhance machinery noise, then noise cancellation or enhancement performance is improved, but echo signals are generated that interfere with voice signal detection

Engineering Contradiction:

Improvemachinery noiseVSAvoidecho signals

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent utilizes the sound management signals that generate echo as reference inputs to the echo canceler. By feeding the same acoustic augmentation signals into the echo canceler, the system can predict and subtract the echo component from the microphone signal, converting the harmful echo into a predictable signal that can be removed.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The echo canceler acts as an intermediary system that processes both the sound management signals and microphone signals. It uses adaptive filtering to create an estimated echo signal from the reference input and subtracts it from the microphone signal, mediating between the acoustic augmentation system and the voice detection system.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multiple audio signals are produced in the vehicle environment, then audio system functionality is enhanced, but isolation of user voice from microphone input becomes more difficult

Engineering Contradiction:

Improveaudio system functionalityVSAvoidvoice signal isolation

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments the total microphone signal into distinct components: user voice, echo from acoustic augmentation, and other audio signals. By using multiple reference inputs in the echo canceler, each signal component can be independently identified and subtracted, allowing precise isolation of the user voice signal.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The echo canceler is designed to handle multiple types of interference signals simultaneously by accepting multiple reference inputs. This multi-functional approach allows the same device to cancel echoes from various sources including acoustic augmentation, entertainment audio, and navigation signals, making the voice isolation system universally applicable to all audio sources.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Effectively reduces echo signals from microphone inputs, improving voice signal quality by isolating user voice from system-generated acoustic signals, thereby enhancing voice processing and user interaction with audio systems.

Implementation Method 1

an acoustic transducer coupled to the signal processor and configured to receive the at least one driver signal and to convert the at least one driver signal into acoustic signals in the listening environment

Methodology Applied

Scientific EffectElectroacoustic transduction:

Implementation Method 2

The echo canceler includes an adaptive filter configured to filter the sound management signal and to provide an estimated echo signal

Methodology Applied

Scientific EffectAdaptive filtering:

Implementation Method 3

a combiner configured to combine the microphone signal and the estimated echo signal to reduce the echo component from the microphone signal

Methodology Applied

Scientific EffectSignal combination:

Data Source

PatentUS11600287B2Cancellation of vehicle active sound management signals for handsfree systems

Publication Date: 2023.03.07 BOSE CORP

AI summary

Audio systems and methods are provided that receive a sound management input signal as a reference signal to remove related content from a microphone signal in, e.g., an automotive hands-free system. The sound management signal may provide an acoustic augmentation to reduce, enhance, or create an acoustic effect, e.g., of an engine, motor, or other operating components. A signal processor receives the sound management signal and the microphone signal, and reduces or removes the sound management signal components from the microphone signal.