Wearable Duplex Audio Layout With Alternating Sampling for Echo Reduction

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Solution Overview

Problem

Echo during duplex communication in wearable devices, such as smartglasses, causes sound distortion and discomfort, rendering calls incomprehensible and painful.

Innovation Solution

The use of a bilateral configuration with microphones and speakers on opposite sides of the wearable device, alternating their activation at a high frequency to reduce echo, utilizing the user's body for occlusion and simulating continuous sound perception.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If all speakers and microphones are activated simultaneously for duplex communication, then communication functionality is improved, but echo and sound distortion increase

Engineering Contradiction:
Improveduplex communication functionalityVSAvoidecho and sound distortion
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies periodic action by rapidly alternating the activation of speaker-microphone pairs in a cycling pattern. Each pair is activated for a brief interval, then deactivated while the next pair activates, creating a periodic switching sequence that maintains continuous communication while preventing echo through temporal separation of transmit and receive operations.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically switches between different speaker-microphone pairs during operation rather than maintaining a static configuration. This dynamic reconfiguration allows the system to adaptively manage echo conditions by ensuring that the active microphone is never on the same side of the user's head as the active speaker, thereby resolving the contradiction between full functionality and echo reduction.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If speakers and microphones are positioned on opposite sides of the wearable device, then echo is reduced through body occlusion, but spatial arrangement complexity increases

Engineering Contradiction:
ImproveechoVSAvoidspatial arrangement
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the audio system into multiple independent speaker-microphone pairs, with each pair assigned to a specific spatial location on the wearable device. This segmentation allows the system to treat each pair as an independent unit that can be selectively activated, simplifying the management of spatial arrangements while effectively utilizing body occlusion to reduce echo for each pair.

Inventive Principle:
Principle #1Segmentation

3Object-affected harmful factors

If alternating sampling is used to prevent echo, then sound quality is improved, but processing complexity increases

Engineering Contradiction:
Improvesound distortionVSAvoidprocessing complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The alternating sampling implements periodic action through a systematic cycling pattern where different speaker-microphone pairs are activated in sequential intervals. This periodic switching creates predictable temporal patterns that reduce echo while maintaining manageable processing complexity through regular, repeatable activation sequences rather than complex adaptive algorithms.

Inventive Principle:
Principle #19Periodic action

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

Reduces echo by minimizing sound interference, maintaining clear communication quality and user comfort during duplex calls.

Implementation Method 1

a first speaker of the array of speakers on a first side of the body, at least one microphone on a second side of the body opposite the first side, where the body occludes sound from the first speaker from reaching the at least one microphone

Methodology Applied
Scientific EffectOcclusion: Absorption (physical)

Data Source

PatentEP3874766B1Alternating sampling method for non-echo duplex conversations on a wearable device with multiple speakers and microphones
Publication Date: 2025.12.24 SNAP INC
  • EP3874766B1 patent drawingFigure 1A
  • EP3874766B1 patent drawingFigure 1B
  • EP3874766B1 patent drawingFigure 1C

AI summary

A wearable device including a body having fasteners and a frame coupled between two fasteners. The frame includes first and second sections. A first portion of the body including the first section of the frame and one fastener and a second portion of the body including the second section of the frame and the other fastener. A speaker and a microphone are connected to the first portion and another speaker and another microphone are connected to the second portion. The body also includes a processor, memory accessible to the processor, and programming in the memory for configuring the processor to selectively activate the speakers and microphones such that a first speaker emits an output sound signal while a first microphone and a second speaker are deactivated and a second microphone captures an input sound signal during the emission of the output sound signal by the first speaker.