An electronic stethoscope was designed to amplify heart and lung sounds while reducing background noise. It uses two microphones, an op-amp quad to amplify the signals by 3x each, and a low-pass filter to remove high frequencies. The filtered signals are sent to a mixer where the user can select the microphone and adjust bass/treble. The signal then goes to an output switch for headphones or speaker. The device aims to perform better than a standard acoustic stethoscope without side effects.
Digital stethoscope a new approach to know and hear heart beat and heart freq...IJARIIT
The motive of this journal is to digitalize the stethoscope and improve and make easier and accurate measurement of
heart beat and frequency rate. The part of the motive of this device is everyone can hear them heart beat and to know about them
health with the help of any instruction and network and also heart beat frequency rate, heart beat sound recorded using
additional devices and the recording signal (heart beat sound or frequency rate) easily transfer by using a smart phone with related
apps.
Evaluating Oticon Medical Ponto Plus and Ponto Pro Sound ProcessorOticon Medical
Performance of the Ponto Plus bone-anchored sound processor from Oticon Medical was evaluated in 19 subjects relative to its predecessor, the Ponto Pro. All subjects had mixed and conductive hearing loss with ample experience with bone-anchored hearing devices. Sixteen subjects were fitted on one side and three subjects on both sides.
One of the new features in Ponto Plus is a link to a body-worn ‘streamer’ for wireless connectivity. The efficacy of wireless signal transfer was tested with speech-in-noise measures. When setting equal wireless and microphone output levels, speech scores were essentially similar, thus confirming the equivalence of both input modes.
Digital stethoscope a new approach to know and hear heart beat and heart freq...IJARIIT
The motive of this journal is to digitalize the stethoscope and improve and make easier and accurate measurement of
heart beat and frequency rate. The part of the motive of this device is everyone can hear them heart beat and to know about them
health with the help of any instruction and network and also heart beat frequency rate, heart beat sound recorded using
additional devices and the recording signal (heart beat sound or frequency rate) easily transfer by using a smart phone with related
apps.
Evaluating Oticon Medical Ponto Plus and Ponto Pro Sound ProcessorOticon Medical
Performance of the Ponto Plus bone-anchored sound processor from Oticon Medical was evaluated in 19 subjects relative to its predecessor, the Ponto Pro. All subjects had mixed and conductive hearing loss with ample experience with bone-anchored hearing devices. Sixteen subjects were fitted on one side and three subjects on both sides.
One of the new features in Ponto Plus is a link to a body-worn ‘streamer’ for wireless connectivity. The efficacy of wireless signal transfer was tested with speech-in-noise measures. When setting equal wireless and microphone output levels, speech scores were essentially similar, thus confirming the equivalence of both input modes.
APPLICATION OF DSP IN BIOMEDICAL ENGINEERING
APPLICATION OF DSP IN BIOMEDICAL ENGINEERING
APPLICATION OF DSP IN BIOMEDICAL ENGINEERING
APPLICATION OF DSP IN BIOMEDICAL ENGINEERING
APPLICATION OF DSP IN BIOMEDICAL ENGINEERING
in this PPT . i tried to explain about hearing Aid , its type , effect , components and how they work..
Might be some mistakes will bw there , sorry for that ...
please suggest me for betterment
FM systems, the best AAC companion for the deaf and hard of hearing.
FM systems are wireless assistive hearing devices that enhance the use of hearing aids, cochlear implants and also assist people who are hard of hearing but do not wear hearing aids, in particular over distance and in noisy environments.
Advantages: Constant SPL which is constant over quiet a distance.
Usable with a wide range of hearing losses. Comes with different electro acoustic output so used with mild HL and severe to profound HL cases.
Frequency characteristics/clarity of signal is good.
It has a large operating range.
No cross-talk between rooms because many FM channels available
Environmental microphones for class participation and self-monitoring
Usable outside of building
Portable and wearable.
Personal hearing aids not needed with self-contained FM system
No spill over as in induction loop system.
Assistive technology for deaf or hard of hearingTural Abdullayev
Types of Assistive devices:
1.Assistive listening devices
2.Augmentative and alternative communication devices
3.Alerting devices
Hearing loop / induction loop systems
FM systems
Infrared systems
Personal amplifiers
Types available for communicating face-to-face:
1. Picture board or touch screen
2. Keyboards, touch screens, and sometimes a person’s limited speech
3. Speech-generating devices
Types available for communicating by the phone:
1, TTY/TDD
2.Relay service
3. Captioned telephones
Phonocardiogram based diagnostic systemijbesjournal
A Phonocardiogram or PCG is a plot of high fidelity recording of the sounds and murmurs made by the
heart with the help of the machine called phonocardiograph. It has developed continuously to perform an
important role in the proper and accurate diagnosis of the defects of the heart. As usually with the
stethoscope, it requires highly and experienced physicians to read the phonocardiogram. A diagnostic
system based on Artificial Neural Networks (ANN) is implemented as a detector and classifier of heart
diseases. The output of the system is the classification of the sound as either normal or abnormal, if it is
abnormal what type of abnormality is present. In this paper, Based on the extracted time domain and
frequency domain features such as energy, mean, variance and Mel Frequency Cepstral Coefficients
(MFCC) various heart sound samples are classified using Support Vector Machine (SVM), K Nearest
Neighbour (KNN), Bayesian and Gaussian Mixture Model (GMM) Classifiers. The data used in this paper
was obtained from Michigan university website.
APPLICATION OF DSP IN BIOMEDICAL ENGINEERING
APPLICATION OF DSP IN BIOMEDICAL ENGINEERING
APPLICATION OF DSP IN BIOMEDICAL ENGINEERING
APPLICATION OF DSP IN BIOMEDICAL ENGINEERING
APPLICATION OF DSP IN BIOMEDICAL ENGINEERING
in this PPT . i tried to explain about hearing Aid , its type , effect , components and how they work..
Might be some mistakes will bw there , sorry for that ...
please suggest me for betterment
FM systems, the best AAC companion for the deaf and hard of hearing.
FM systems are wireless assistive hearing devices that enhance the use of hearing aids, cochlear implants and also assist people who are hard of hearing but do not wear hearing aids, in particular over distance and in noisy environments.
Advantages: Constant SPL which is constant over quiet a distance.
Usable with a wide range of hearing losses. Comes with different electro acoustic output so used with mild HL and severe to profound HL cases.
Frequency characteristics/clarity of signal is good.
It has a large operating range.
No cross-talk between rooms because many FM channels available
Environmental microphones for class participation and self-monitoring
Usable outside of building
Portable and wearable.
Personal hearing aids not needed with self-contained FM system
No spill over as in induction loop system.
Assistive technology for deaf or hard of hearingTural Abdullayev
Types of Assistive devices:
1.Assistive listening devices
2.Augmentative and alternative communication devices
3.Alerting devices
Hearing loop / induction loop systems
FM systems
Infrared systems
Personal amplifiers
Types available for communicating face-to-face:
1. Picture board or touch screen
2. Keyboards, touch screens, and sometimes a person’s limited speech
3. Speech-generating devices
Types available for communicating by the phone:
1, TTY/TDD
2.Relay service
3. Captioned telephones
Phonocardiogram based diagnostic systemijbesjournal
A Phonocardiogram or PCG is a plot of high fidelity recording of the sounds and murmurs made by the
heart with the help of the machine called phonocardiograph. It has developed continuously to perform an
important role in the proper and accurate diagnosis of the defects of the heart. As usually with the
stethoscope, it requires highly and experienced physicians to read the phonocardiogram. A diagnostic
system based on Artificial Neural Networks (ANN) is implemented as a detector and classifier of heart
diseases. The output of the system is the classification of the sound as either normal or abnormal, if it is
abnormal what type of abnormality is present. In this paper, Based on the extracted time domain and
frequency domain features such as energy, mean, variance and Mel Frequency Cepstral Coefficients
(MFCC) various heart sound samples are classified using Support Vector Machine (SVM), K Nearest
Neighbour (KNN), Bayesian and Gaussian Mixture Model (GMM) Classifiers. The data used in this paper
was obtained from Michigan university website.
Graphic record heart sound - Phonogram.
Recording the sounds connected with the pumping action of heart.
Sound from heart – phonocardiogram
Instrument to measure this – phonocardiograph
Basic function – to pick up the different heart sound,filter the required and display.
An Examination of Effectuation Dimension as Financing Practice of Small and M...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Does Goods and Services Tax (GST) Leads to Indian Economic Development?iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Childhood Factors that influence success in later lifeiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Emotional Intelligence and Work Performance Relationship: A Study on Sales Pe...iosrjce
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IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
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IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Consumer Perspectives on Brand Preference: A Choice Based Model Approachiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Student`S Approach towards Social Network Sitesiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Broadcast Management in Nigeria: The systems approach as an imperativeiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
A Study on Retailer’s Perception on Soya Products with Special Reference to T...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
A Study Factors Influence on Organisation Citizenship Behaviour in Corporate ...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Consumers’ Behaviour on Sony Xperia: A Case Study on Bangladeshiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Design of a Balanced Scorecard on Nonprofit Organizations (Study on Yayasan P...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Public Sector Reforms and Outsourcing Services in Nigeria: An Empirical Evalu...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Media Innovations and its Impact on Brand awareness & Considerationiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Customer experience in supermarkets and hypermarkets – A comparative studyiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Social Media and Small Businesses: A Combinational Strategic Approach under t...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Secretarial Performance and the Gender Question (A Study of Selected Tertiary...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Implementation of Quality Management principles at Zimbabwe Open University (...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Organizational Conflicts Management In Selected Organizaions In Lagos State, ...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Design and Analysis of Algorithms-DP,Backtracking,Graphs,B&B
A versatile low cost Electronic Stethoscope design
1. IOSR Journal of Electronics and Communication Engineering (IOSR-JECE)
e-ISSN: 2278-2834,p- ISSN: 2278-8735.Volume 10, Issue 6, Ver. I (Nov - Dec .2015), PP 48-54
www.iosrjournals.org
DOI: 10.9790/2834-10614854 www.iosrjournals.org 48 | Page
A versatile low cost Electronic Stethoscope design
Olumuyiwa Oludare FAGBOHUN
Department of Electrical Engineering, Faculty of Engineering, Ekiti State University, Ado-Ekiti,Nigeria
Abstract: To develop an electronic stethoscope to amplify the sound of the heart and reduce any background
ambient noise thereby producing a perfect heart beat sound for hearing, and to verify the ability of the
electronic stethoscope in performing a better function than the medical acoustic type without any side effect on
the people, is the aim of this work. The device is developed and consists of two microphones whose signals are
sent through a quad amp which implements an initial gain of three and filters the input via a five pole Sallen-
Key low pass filter. The two filtered signals are sent to a mixer, which allows the user to select which input
microphone they would like to use and adjust the bass and treble characteristics of the signal. Following the
mixer, the signal is sent to another switch, which allows the user to choose between headphone or speaker
output.
I. Introduction
Stethoscope is one of the most important diagnostic tools in the medical world. Over almost two
centuries, the stethoscope has been changed and refined often, but it has never strayed too far from the original
design. Rene Theophile, a French physician, is attributed with the invention of the first stethoscope in 1816
when he was examining an obese patient. His first model of the stethoscope was simply a wooden tube
resembling a candlestick. Over the years, this model has evolved into the device that we now recognize as the
stethoscope through many small changes, such as adding earpieces for each ear and developing the combined
bell and diaphragm chest piece [1]. A stethoscope is a very straightforward device. The chest piece consists of a
shallow, bell-shaped piece and a clear, stiff diaphragm, which is then connected to the metal earpieces by a
flexible tube [1,2]. The bell is used to pick up lower frequency sounds, and the diaphragm is used for higher
frequency sounds. When the chest piece is placed on the skin, vibrations within in the body are amplified by
either the bell or diaphragm. These acoustic pressure waves then travel up through the tubing, resonating to the
earpieces and into the listener’s ears.
Very few changes have been made to the overall design of the stethoscope over the years because it
does its job so well. However, there are a few problems with current models. For example, with the standard
acoustic stethoscope, the listener is not able to amplify the sounds. This is sometimes a problem if he or she is
only getting very quiet sounds through the stethoscope. Also, the earpieces of stethoscopes can be quite
uncomfortable. Although these are not enormous problems, current technology has introduced alternatives to the
acoustic stethoscope.Stethoscopes are not only useful for doctors, but for home mechanics, exterminators,
spying etc [2,3]. Stethoscopes can also be used to check scientific vacuum chambers for leaks, and for various
other small-scale acoustic monitoring tasks. Standard stethoscope provides no amplification which reduces its
use [2,3]. A Stethoscope uses op-amps to amplify the signal and includes a low pass filter to remove background
noise.
A typical electronic stethoscope performs the following functions [3,4];
For listening to the heart beats for any irregular rate of beating.
To verify the operation of the lungs to know if there is fluid build up.
To check the blood pressure running through the veins.
To determine the process of digestive system in the stomach.
For prenatal care during pregnancy.
The field of applied science related to the art of healing by diagnosis, treatment, and prevention of
disease. It encompasses a variety of health care practices evolved to maintain and restore health by the
prevention and treatment of illness in human beings.Contemporary medicine applies biomedical sciences,
biomedical research, genetics and medical technology to diagnose, treat, and prevent injury and disease,
typically through medication or surgery, but also through therapies as diverse as psychotherapy, external splints
& traction, prostheses, biologics, pharmaceuticals, ionizing radiation among others [4].
2. A versatile low cost Electronic Stethoscope design
DOI: 10.9790/2834-10614854 www.iosrjournals.org 49 | Page
II. Types of stethoscope
2.1. Acousticstethoscope
The stethoscope is an instrument used for auscultation or listing to sounds produced by the body. It is
used primarily to listen to the lungs, heart and intestinal tract. It is also used to listen to blood flow in peripheral
vessels and the heart sounds of development.
Acoustic stethoscopes are familiar to most people, and operate on the transmission of sound from the
chest piece, via air-filled hollow tubes, to the listener's ears. The chest piece usually consists of two sides that
can be placed against the patient for sensing sound; a diaphragm (plastic disc) or bell (hollow cup). If the
diaphragm is placed on the patient, body sounds vibrate the diaphragm, creating acoustic pressure waves which
travel up the tubing to the listener's ears. If the bell is placed on the patient, the vibrations of the skin directly
produce acoustic pressure waves traveling up to the listener's ears [3,4]. The bell transmits low frequency
sounds, while the diaphragm transmits higher frequency sounds. This two-sided stethoscope was invented by
Rappaport and Sprague in the early part of the 20th century. One problem with acoustic stethoscopes was that
the sound level is extremely low. This problem was surmounted in 1999 with the invention of the stratified
continuous (inner) lumen, and the kinetic acoustic mechanism in 2002. Acoustic stethoscopes are the most
commonly used. A recent independent review evaluated twelve common acoustic stethoscopes on the basis of
loudness, clarity, and ergonomics. They did acoustic laboratory testing and recorded heart sounds on volunteers.
The results are listed by brand and model.
2.2 Electronicstethoscope
An electronic stethoscope (stetho-phone) overcomes the low sound levels by electronically amplifying
body sounds. However, amplification of stethoscope contact artefacts, and component cut-offs (frequency
response thresholds of electronic stethoscope microphones, pre-amps, amps, and speakers) limit electronically
amplified stethoscopes' overall utility by amplifying mid-range sounds, while simultaneously attenuating high-
and low- frequency range sounds. Currently, a number of companies offer electronic stethoscopes. Electronic
stethoscopes require conversion of acoustic sound waves to electrical signals which can then be amplified and
processed for optimal listening. Unlike acoustic stethoscopes, which are all based on the same physics,
transducers in electronic stethoscopes vary widely. The simplest and least effective method of sound detection is
achieved by placing a microphone in the chest piece. This method suffers from ambient noise interference and
has fallen out of favour. Another method, used in Welch-Allyn'sMeditron stethoscope, comprises placement of a
piezoelectric crystal at the head of a metal shaft, the bottom of the shaft making contact with a diaphragm [5,6].
3M also uses a piezo-electric crystal placed within foam behind a thick rubber-like diaphragm. Think labs'
Rhythm 32 inventor, Clive Smith uses an Electromagnetic Diaphragm with a conductive inner surface
to form a capacitive sensor. This diaphragm responds to sound waves identically to a conventional acoustic
stethoscope, with changes in an electric field replacing changes in air pressure. This preserves the sound of an
acoustic stethoscope with the benefits of amplification.Because the sounds are transmitted electronically, an
electronic stethoscope can be a wirelessdevice, can be a recording device, and can provide noise reduction,
signal enhancement, and both visual and audio output [6]. Around 2001, Stetho-graphics introduced PC-based
software which enabled a phonocardiograph, graphic representation of cardiologic and pulmonology sounds to
be generated, and interpreted according to related algorithms. All of these features are helpful for purposes of
telemedicine (remote diagnosis) and teaching.Electronic stethoscopes are also used with Computer-aided
Auscultation programs to analyse the recorded heart sounds pathological or innocent heart murmurs.
2.3 Recording stethoscopes
Some electronic stethoscopes feature direct audio output that can be used with an external recording
device, such as a laptop or MP3 recorder. The same connection can be used to listen to the previously-recorded
auscultation through the stethoscope headphones, allowing for more detailed study for general research as well
as evaluation and consultation regarding a particular patient's condition and telemedicine, or remote diagnosis
[7].
III. Methodology of research
The components used for the design of an electronic stethoscope are as listed below:-
a). Chest piece
b). A pre amplifier circuit
c). Operational amplifier circuits
d). a low pass filter circuit
e). Electret microphone
f). Regulators consisting of resistor circuits and capacitors
g). Earpiece
3. A versatile low cost Electronic Stethoscope design
DOI: 10.9790/2834-10614854 www.iosrjournals.org 50 | Page
h). 12 Volts power source
f). Output (ear piece/ loud speaker)
When the chest piece is placed on the patient, the earpiece allows the internal sound energy from the
patient through the conductor travels through the ear of the clinician or medical personnel. The physical
connection is made between the ear tips and the human ear. The pressure, ear tip seal, ear tip insertion angle are
all variables that can affect the connection.The chest piece usually consist of two parts that can be placed on the
patient for sensing sound i.e. low frequency sound when the diaphragm is placed against the body of the patient
skin, body sound vibrates the diaphragm creating acoustic pressure wave which can travel to the listeners ear.
The large side can be used for adult patient while the small side is especially useful for paediatric or thin patient,
around bandages and carotid assessment. The human body translates the pressure wave into sound and allows
the listener to hear what they are examined.Hence, the chest piece is part of the stethoscope that is placed on a
location where the users wants to hear sound
Figure 1: Chest piece separated from the stethoscope. (The American Journal of Cardiology)
Amplifiers are referred to active circuits since there operation is based on active devices. They are
distinguished from passive circuits by their ability to provide power gain, which is essential to most electronic
systems. This need for power gain is most evident in wireless communication systems, where the signal
received may be in the microvolt range, which is too weak to process without amplification. Small signal
amplifiers are used to increase the voltage amplitude and/or the current amplitude of a signal, to provide some
increase in the power of the signal [11]. Transistors can be used in virtually all small signal amplifiers, either
built into an integrated circuitor used in the discrete form. The choice of the either NPN or PNP bipolar or FET
depends on the design consideration. In this work, a FET transistor was selected. FETs are different from the
bipolar junction transistor in that they amplify voltage changes at the input into current changes at the output.
That is, they depend on the voltage change between the gate and the source to produce a current change between
drain and source. Their large resistance looking into the gate is a property very useful to its selection.
Filters are used in circuits which require the separation of signals according to their frequencies. A low
pass filter is provided to remove high frequency noise and also acts as an anti-aliasing filter, since sigma delta
ADC (codec) is chosen, the requirement on the analog anti-aliasing filters are minimal.This is because over
sampling relaxes the requirement on the base band anti-aliasing filter. Therefore, a simple first order active low-
pass filter is sufficient.The simplest way to make a filter is by using passive components(RLC) which works
well for high frequencies. However, at audio frequencies, the inductors become problematic, as it becomes very
large [12]heavy and expensive. For low frequency application as this design demands, a low pass active filter is
selected, with second order Butterworth at an upper cut off frequency of 400Hz.
Basically, op-amp is such an amplifier which as a very high sensitivity and gain. If it gets a small
amount of input voltage, it can amplify it very well. Thus, the amplification depends on the supply voltage, if
the gain is high enough, the output voltage will be crossing the operating voltage, hence it will saturates and its
output voltage will be the same as its operating voltage.The operational amplifier (Op-Amp) used is in the
inverting mode used as a preamplifier circuit with a design gain of -100. The inverting signal is re-inverted for
balance the phase shift with another op-amp of a gain of -100. The power amplifier is developed with the use of
a push pull op-amp to give the desired current range to drive the output transducer.
The electrets microphone used, picks up a negligible sound and converts it to an electrical format,
reason because an electrets mic is a transducer that converts one form of energy to another (basically sound
energy to electrical energy).
4. A versatile low cost Electronic Stethoscope design
DOI: 10.9790/2834-10614854 www.iosrjournals.org 51 | Page
IV. Operational analysis of an electronic stethoscope
Some stethoscope must be placed directly on the skin, while others can work effetely through clothing.
For the stethoscope, listeners place the chest piece on the area to be tested and a low-pitched or low frequency
sound is heard.A stethoscope is used in conjunction with a device to measure blood pressure
(sphygmomanometer). The stethoscope detects sound of blood passing through artery.
Figure 2: Block Diagram of an Electronic Stethoscope
Figure 3: Circuit design for an electronic stethoscope.
The operation of the circuit may be understood from the assumption that when a small a.c signal is
applied to the gate, it produces variations in the gate-to-source voltage. This produces variations in the drain
current. As the gate-to-source voltage increases, the drain current also increases, and the voltage drop across the
resistor R2 also increases. This causes the drain voltage to decrease. It means that the positive half cycle of the
output voltage (i.e. the output voltage at the drain is 1800
out- of phase with the input voltage at the gate. The a.c
equivalent circuit of a common source amplifier obtained by short-circuiting the capacitors and the d.c supplies,
with the FET replaced by its low frequency model [15,16], shows that,
Av = Vo/ Vin ………1
And the current through R2 = Rd (by current divider rule ) is
id = rd(gm . vgs) / (Rd + rd) ……2
where gm is the FET transconductance in mA/V or mS; and vgsis the gate –to- source voltage.
The output voltage is,
Vo = - id .Rd = - Rd . rd(gm . vgs) / (Rd + rd)
= - gm .Rd rd . vgs = - gm . rL .vgs …..3
( rL= (Rd rd))
Thus,
Vo = - gm . rL .vin ……4
Therefore,
Av = Vo/ Vin = - gm . rL
R1
1.5kΩ
5%
1122
R2
100kΩ
5%
1122
C2
100uF
10%
2211
1
C1
10uF
10%
2 211
R4
4.7kΩ
5%
1122
C3
10uF
10%
2 211
V1
0.001 Vpk
100 Hz
0°
12
V2
12 V
21
Q1
J112
S1D3
G2
U1A
TL072ACD
R3
2.2kΩ
5%
R5
2.2kΩ
5%
R6
47kΩ
5%
V3
12 V
21
V4
12 V
21
U2A
TL072ACD
R7
2.2kΩ
5%
R8
2.2kΩ
5%
R9
47kΩ
5%
V5
12 V
21
V6
12 V
21
XSC1
A B C D
G
T
1
2
3
4
6
5
Q2
2N4403
E3C1
B2
LS1
BUZZER
200 Hz
11
22
R12
1.5kΩ
5%
1122
1
C5
10µF
10%
2 211
C6
100µF
10%
2 211
V7
12 V
21
R14
5kΩ
5%
12
R15
100Ω
5%
1122
D1
1N4001GP
K2A1
D2
1N4001GP
K2A1
R16
5kΩ
5%
12
C7
10µF
10%
2 211
Q3
2N3904
E2C1
B3
Q4
2N3906
E2C1
B3
R10
1kΩ
5%
11 2 2
R11
30Ω
5%
1122
1
C4
10nF
5%
2211
L1
1mH
5%
12
R17
1.5kΩ
5%
1122
Electret
Mic
Control
Module
Output
Stage
5. A versatile low cost Electronic Stethoscope design
DOI: 10.9790/2834-10614854 www.iosrjournals.org 52 | Page
And the input resistance
Ri = Vin/ iin
with the output resistance
R’o = ( rL= Rd rd)
And the voltage gain ,
Av = - gm .rL
Substituting the values of the parameters for 2N4416 FET : Vgs = -6v, Pd = 300mW, Vdg= 35, Vdss=
30V , Idss= 5mA and, Igss= 100pA and rd = 100k then ;
rL= Rd rd = Rd xrd = 10 x 100 = 1000/110 = 9.09k
Rd +rd 10 +100
From shockey’s equation [15],
ID =IDss( 1 – Vgs/ Vp)2
…. 5
Where ,
dID = gm = -2 IDss( 1 – Vgs/ Vp) …….. 6
dIDssVp
substituting the values, we have from equation 6,
ID = 5x 10-3
( 1 – (-6)/(-3) )2
= 5mA
Thus ,
Rs = Vgs/ Ip = 6/ 0.005 = 1.2kΩ
And from
VDs = VDD - ID ( RD + Rs) with VDs = VDD /2 , we have
= 9 + 6 - 5 x 10 -3
RD
And
RD = 2.1 kΩ, where we select 2.2 kΩ
From equation 6,
gm = -2 x 5x 10-3
( 1 – (-6)/(-3) )
-3
= 3.333 x 10-3
S = 3.33mS.
The class B push-pull amplifier is designed for the buffer which consist of capacitors C1, C2 and C3 are
coupling capacitors to prevent the transistor dc bias voltages from being affected by the input circuit or the load
circuit. The amplifier voltage gain is measured by dividing the ac peak to peak output voltage Vo by the ac peak
to peak input voltage Vin. Because the push pull is an emitter follower configuration, the voltage gain should be
close to unity.
The design was simulated on a multism -10 version, with an input sinusoidal voltage of 1microvolt,
and the output response is as shown with measured signals of figure 4.The output voltage from the pre amplifier
circuit with transistor T1 gives 1.8uV, while the output response from the op-amp 2 gives a voltage of 3.54mV.
The output from the op-amp serves as an input to a low pass filter circuit with 101uV and the output fed to a
push pull amplifier which gives a voltage of 6.02V to drive the output device, which in this design is a 200Hz
buzzer.Also, a square wave form was used as an input with results of figure 5. The output voltage from the pre
amplifier circuit with transistor T1 gives 0.100mV, while the output response from the op-amp 2 gives a voltage
of 100mV. The output from the op-amp serves as an input to a low pass filter circuit and the output fed to a push
pull amplifier which gives a voltage of 140mV to drive the output device An impulse voltage of 0.1mV was
used as an input with a design parameter of initial value of -1mV, pulse voltage of 1uV, delay time of zero volts,
rise and fall time of 1ns and a pulse width of 0.5ms. The response the design is as shown in figure 6. The output
voltage from the pre amplifier circuit with transistor T1 gives 2.75uV, while the output response from the op-
amp 2 gives a voltage of 3.64mV. The output from the op-amp serves as an input to a low pass filter circuit and
the output fed to a push pull amplifier which gives a voltage of 6.02Vto drive the output device Apart from the
low cost value of the design at less than N15,000(fifteen thousand Naira only) Nigerian currency compared to
the acoustic value type of about N25,000 (Twenty thousand Naira only); the development gives a very clear
sound from the output response device, with better sensitivity.
6. A versatile low cost Electronic Stethoscope design
DOI: 10.9790/2834-10614854 www.iosrjournals.org 53 | Page
Figure 4: Analysis of design response at various points of measurement with sinusoidal input.
Figure 5: Analysis of design response at various points of measurement with sinusoidal input.
Figure 6: Analysis of design response at various points of measurement with pulse input.
7. A versatile low cost Electronic Stethoscope design
DOI: 10.9790/2834-10614854 www.iosrjournals.org 54 | Page
A stethoscope functions in a way that it is used by healthcare professional to examine and evaluate
their patients, typically, it is used to listen to the rhythm or sound made by the body since faints beat cannot be
heard by mere ear except with a stethoscope. For the heart, normally it beats at an even rate, when the
stethoscope is placed on it, it is heard by the healthcare professional both normal and also abnormal sound can
be heard such as; murmur, irregular rate and other sound that might not be normal.Hence, the rhythm of one’s
heartbeat can be heard through a stethoscope to determine if there are any abnormal sounds. For the lungs, it is
helpful to determine if there is a fluid build-up in the lungs and if there are any breathing difficulties.If someone
or a patient has a common flu or cold or suffer from abnormal breathing condition, medical personnel can listen
to the breathing sound by placing the stethoscope on the lungs and a sound is heard that alerts them to
inflammation the air passage and fluid and congestion. To monitor the blood pressure, the blood running
through the vein can be heard with the use of stethoscope, this is another way to count the heartbeats and listen
to the blood running through the veins. When the blood pressure cuff is inflated on the arms, medical personnel
are trained to hear the heart beating in the veins. The first beat they hear is the top number of the blood pressure
and the last beat they hear is the bottom number. In the digestive system i.e. stomach of a patient, the sounds
made by the intestines and other parts of the stomach can be listened to by the stethoscope, this can aid in
determining if there are any stomach disorders or internal abnormalities. It also aids food digestion and even
when the digestive system is empty, the stomach and bowels makes popping and gurgling noises. Some noises
maybe heard by the ears but stethoscope is much more sensitive to these noises, the absence of some could
means an obstruction in your bowels and a large number of noise could signal or signifies an infection or illness.
It is equally of note very useful in prenatal care, as an obstetrician uses a stethoscope to listen a baby’s
heartbeat in the uterus or listen to the baby’s movement in the womb.During pregnancy, the movement of the
baby, the heartbeat of the baby in the womb can be monitored by a stethoscope. Using stethoscope, the listener
can hear normal and abnormal respiratory, cardiac, pleural, arterial, venoms, interne, foetal and intestinal sound.
The advantages of an electronic stethoscope over acoustic type include; i. It is more sensitive than the
acoustic type, ii. the output sound can be varied i.e. (distinct sound output), iii. it can be connected to an external
sound amplifier and the sound can be heard by all persons present in the place for training and lecturing
purposes, iv. It produces a clearer output sound compare to the acoustic type; while the disadvantages include: i.
It is expensive and ii. It has a high cost of maintenance, iii. It is useless if the battery is down or drained.
V. Conclusions
Electronic stethoscope is a device used to measure blood pressure by detecting the blood sound
pressure, heart and lungs beat, digestive system of the stomach, prenatal care (pregnancy). The project aim at
designing an electronic stethoscope, a circuit is design to perform the same function as the conventional
stethoscope.
The entire circuit runs on a 12v battery source using a low cost electronic component like resistors,
capacitors, and op-amps and the required design is achieved.
References
[1]. J. Leyden, (2001): The Chance Invention that Changed Medicine. Saturday Evening Post, pp. 46-73.
[2]. Standris Medical Supply, Inc. (2011):History of Stethoscopes. Retrieved October 23, 2011, from Standris Medical Supply, Inc.
[3]. M. Lambe, (2009):How Does the Stethoscope Work. Retrieved November 15, 2011, from Livestrong.com:
http://www.livestrong.com/article/30071
[4]. M.C. Grenier, K. Gagnon, J. Genest, J. Durand, L.G. Durand, (1998): Clinical Comparison of Acoustic and Electronic Stethoscopes
and Design of a New Electronic Stethoscope. The American Journal of Cardiology, pp. 653-656.
[5]. D.J. Griffiths,(2008):Development of Ionic Polymer Metallic Composites as Sensors. Retrieved October 23, 2011, from .doctor:
[6]. D. Birrenkott, B. Wendorff, J. Ness and C, Durante,(2011): Heart & Breath Sounds Amplifier. Madison: University of Wisconsin-
Madison Department of Biomedical Engineering.
[7]. Opt acoustics. (2011):Technology: Core Sensor Platform. Retrieved October 22, 2011, from Optoacoustics:
http://www.optoacoustics.com/technology/core-sensor-platform
[8]. Analog Devices (2011):ADMP401: Omnidirectional Microphone with Bottom Port and Analog Output. Retrieved October 15,
2011, from Analogue Devices:
[9]. Texas Instruments. (2011): Wireless Connectivity Solutions: Bluetooth Technology. Retrieved October 23, 2011, from Texas
Instruments:
[10]. Texas Instruments.(2011):PurePath Wireless Audio. Retrieved October 23, 2011, from Texas Instruments: J. Cerezo,
(n.d.):Application Note AN-1070: Class D Audio Amplifier Performance Relationship to MOSFET Parameters. Retrieved October
22, 2011, from International Rectifier: http://www.irf.com/technical-info/appnotes/an-1070.pdf
[11]. R. Gomez, (2009):PowerWise Class G versus Class AB Headphone Amplifiers.Retrieved 22 October, 2011, from National
Semiconductor: