Electronic Stethoscope Noise Cancellation with Dual Microphones

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Solution Overview

Problem

Existing electronic stethoscopes lack effective noise cancellation and filtering capabilities, leading to interference from environmental noise during auscultation, which can obscure the detection of body sounds of interest.

Innovation Solution

An electronic stethoscope design with a dual-microphone system, where one microphone detects body sounds and another detects ambient noise, combined with mechanical and electronic noise cancellation techniques, to isolate and filter out unwanted noise, using a switching valve to switch between acoustic and digital modes of operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If electronic components are added to convert acoustic stethoscope to digital mode, then sound digitization and wireless transmission capabilities are improved, but device complexity increases

Engineering Contradiction:
Improvesound digitization capabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

An electronic stethoscope device is introduced as an intermediary component that connects between the acoustic stethoscope and digital systems. This intermediary performs sound digitization, noise cancellation, and wireless transmission functions, allowing the simple acoustic stethoscope to gain digital capabilities without modifying its core structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The electronic stethoscope device is designed to perform multiple functions: sound digitization, noise cancellation, signal filtering, and wireless transmission. This multi-functional approach consolidates various capabilities into a single device, reducing overall system complexity while enhancing adaptability.

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

2Measurement precision

If noise cancellation processing is added to filter environmental noise, then auscultation sound clarity is improved, but device complexity increases

Engineering Contradiction:
Improveauscultation sound clarityVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The noise cancellation system uses feedback mechanisms where the captured auscultation sound is processed through digital signal processing algorithms. The system continuously analyzes the sound signal, identifies noise components, and subtracts them from the original signal, improving clarity through iterative refinement.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Traditional mechanical noise filtering methods are replaced with electronic and digital signal processing techniques. The electronic stethoscope device uses digital algorithms to cancel noise, which is more effective and can be implemented with relatively simple electronic components compared to complex mechanical filtering systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If signal filtering is applied to focus on body sounds, then detection precision is improved, but loss of information may occur

Engineering Contradiction:
Improvedetection precisionVSAvoidloss of information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The signal filtering process applies different processing characteristics to different frequency ranges. Frequency bands corresponding to typical body sounds (heart, lung, bowel sounds) are enhanced and preserved, while environmental noise frequencies are attenuated. This selective filtering maintains detection precision for relevant sounds while minimizing information loss.

Inventive Principle:
Principle #3Local quality

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

Improves noise cancellation processing, enhancing the clarity and specificity of auscultation sounds by reducing unwanted feedback and environmental noise interference, allowing for clearer analysis and transmission of body sounds.

Implementation Method 1

a first microphone that receives the auscultation sound and converts the auscultation sound into an auscultated electronic signal

Methodology Applied
Scientific EffectMicrophone transduction:

Implementation Method 2

a second microphone that is mechanically isolated from the airway, the speaker, and the first microphone that receives ambient noise and converts the ambient noise into an electronic audio signal

Methodology Applied
Scientific EffectMicrophone transduction:

Implementation Method 3

The CPU and/or the electronic acoustic modifier process the auscultation electronic signal and the electronic audio signal to generate a processed electronic signal

Methodology Applied
Scientific EffectActive noise cancellation:

Implementation Method 4

using a switching valve to switch between acoustic and digital modes of operation

Methodology Applied
Scientific EffectValve control: Valve

Data Source

PatentEP4033982B1Electronic stethoscope device with noise cancellation
Publication Date: 2025.07.16 EKO HEALTH INC
  • EP4033982B1 patent drawingFigure 1A~1B
  • EP4033982B1 patent drawingFigure 2A
  • EP4033982B1 patent drawingFigure 2B

AI summary

An electronic stethoscope device can be integrated into a conventional stethoscope to digitize auscultated sounds from the body of a patient. The device can be switched off so that the conventional stethoscope can be used as a standard stethoscope. When the device is switched on, the digitized auscultated sounds can be modified to remove the noise. Such modified sounds can be sent wirelessly from the electronic stethoscope device to a peripheral device that can receive such wireless signals, such as computer, cell phone, or cloud application, where the data can be viewed and manipulated further as desired.