简介：
A 12-lead ECG data acquisition system based on ADS1298 is presented in this paper. ADS1298 is a latest 16-channel 24-bit Analog to Digital Converter (ADC) made in TI Company, which has the characters of high-precision,low power and low noise, with the internal integration of the input multiplexers, analog low-pass filter, and digitalfilter, etc. Combined with the high-speed low-power chip M051 as MCU, it can achieve the standard 12-leadsimultaneous ECG acquisition. ECG data can also be transmitted to an upper host PC though nRF24LE1 MCU. Thissystem greatly compact the circuit and reduce the power cost, as well as implement the wireless transmission. It haslaid the foundation for the future high-accuracy portable ECG instrument.
简介：
Cardiovascular diseases are directly or indirectly responsible for up to 38.5% of all deaths in Germany and thus represent the mostfrequent cause of death. At present, heart diseases are mainly discovered by chance during routine visits to the doctor or whenacute symptoms occur. However, there is no practical method to proactively detect diseases or abnormalities of the heart in thedaily environment and to take preventive measures for the person concerned. Long-term ECG devices, as currently used byphysicians, are simply too expensive, impractical, and not widely available for everyday use. This work aims to develop an ECGdevice suitable for everyday use that can be worn directly on the body. For this purpose, an already existing hardware platform willbe analyzed, and the corresponding potential for improvement will be identified. A precise picture of the existing data quality isobtained by metrological examination, and corresponding requirements are defined. Based on these identified optimizationpotentials, a new ECG device is developed. The revised ECG device is characterized by a high integration density and combinesall components directly on one board except the battery and the ECG electrodes. The compact design allows the device to beattached directly to the chest. An integrated microcontroller allows digital signal processing without the need for an additionalcomputer. Central features of the evaluation are a peak detection for detecting R-peaks and a calculation of the current heart ratebased on the RR interval. To ensure the validity of the detected R-peaks, a model of the anatomical conditions is used. Thus,unrealistic RR-intervals can be excluded. The wireless interface allows continuous transmission of the calculated heart rate.
Following the development of hardware and software, the results are verified, and appropriate conclusions about the data qualityare drawn. As a result, a very compact and wearable ECG device with different wireless technologies, data storage, and evaluationof RR intervals was developed. Some tests yelled runtimes up to 24 hours with wireless Lan activated and streaming.
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This paper presents a fully integrated wirelesselectrocardiogram (ECG) SoC implemented in asynchronousarchitecture, which does not require system clock as well asoff-chip antenna. Several low power techniques are proposedto minimize power consumption. At the system level, a newlyintroduced event-driven system architecture facilitates the asynchronous implementation, thus removes the system clock leadingto a true ECG-on-chip solution. A DC-coupled analog front-endis introduced together with a baseline stabilizer to boost the inputimpedance to 3.6 G and mitigate the electrode offset, which isless sensitive to motion artefact and contact impedance imbalance, making it well suited for dry-electrode based applications.
Level-crossing analog-to-digital converter (LC-ADC) is employedto take the advantage of burst nature of ECG signal leading to atleast 5 times reduction in sampling points compared to Nyquistsampling. A digitally implemented impulse-radio ultra-widebandtransmitter is seamlessly integrated with LC-ADC and an on-chipantenna for wireless communications. Implemented in 0.13 μmCMOS technology, the ECG-on-chip consumes 2.89 μW under1.2 V supply while transmitting the raw ECG data, which attainsone order of magnitude lower than the current state-of-the-artdesigns. The fully integrated ECG SoC requires no externalclocks and off-chip antenna, making it a good candidate for lowcost and disposable wireless ECG patches, such as epidermalelectronics.
Index Terms— Electrocardiogram (ECG), dry-electrode, highinput impedance IA, DC-coupled IA, event-driven, level-crossingADC, asynchronous, clockless, impulse-radio, wearable biomedical sensor, epidermal electronics.
简介：
The aim of this paper is to present a wireless biomedical system for the acquisition and transmission(Wibio’ACT) of biomedical signals. This work is a part of the Wibio’ACT project which main purpose is toensure the minimum power consumption while diagnose patients continuously and in real time. For theWibio’ACT system, the bottleneck is the analog-to-digital conversion (ADC) since it controls the powerconsumption of the digital signal processing step as well as the amount of the transmitted data. In fact, inthis work case, the ADC continuously measures the electrical activity of the heart to deliver theelectrocardiogram (ECG) signal. Hence, among conventional ADCs, level-crossing analog-to-digitalconverters (LC-ADCs) have been investigated for ECG signals processing. Authors propose some designconsideration of the LC-ADC. This reduces the LC-ADC output samples by 13 % to help to save the powerconsumption of the wireless data transmitter. The samples with a small variation are reduced by at least44%. The performance of the proposed design is measured in terms of percentage root mean squaredifference (PRD) applied to the reconstructed signal quality. A PRD of 1% is verified using behavioralsimulations on ECG records extracted from different databases. A timer period TC of 0.14 ms ensures aneffective number of bits of 10 bits and a signal to noise ratio of 62 dB.
简介：This document discusses the characteristics of electrocardiogram (ECG) signals and different front-endapproaches for ECG signal acquisition. The tradeoffs between different approaches and the effects onoverall system design are discussed. The report also includes descriptions of potential implementations ofthe front-end architecture using the ADS1258 and ADS1278 and respective noise measurement results.
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The level crossing ADC generates digitized samples consisting of the magnitude of input signal and time interval between twoconsecutive level crossings when the input signal crosses the threshold level. This paper presents a new architecture of low powerasynchronous adaptive threshold level crossing (LC) ADC suitable for wearable ECG sensors based on a novel algorithm fordetermining adaptive threshold. The adaptive threshold was determined by calculating the mean of maximum and minimumvalues of signal in a predetermined window. Polynomial interpolation was used to reconstruct the signal. A signal to noisedistortion ratio of 57.50 dB and a mean square error (MSE) measure of 1.368*10?8 V2 was achieved by the proposed algorithmfor a 1 mV, 10 Hz input sinusoidal signal in MATLAB. The asynchronous adaptive threshold LC ADC operating from a supplyvoltage of 0.8 V occupied a layout area of 266.33*331.385 μm2 when implemented in CADENCE virtuoso using 180 nmtechnology. The designed circuit consumes an average power of 367.6 nW for a 1mVpp, 10 Hz input sinusoidal signal whensimulated in Virtuoso.
简介：The development of portable ECG technology has found growing markets, from wearableECG sensors to ambulatory ECG recorders, encountering challenges of moderately complex totightly regulated devices. This study investigated how a typical 0.5–40 Hz bandwidth ECG isaffected by motion artifact when using analog front-end (AFE) integrated circuits such as theAD823X family. It is known that the typical amplitude resolution of current mobile health ECGdevices is 10–12 bits, and sometimes 16-bits, which is enough for monitoring but might beinsufficient to identify the small potential amplitudes useful in diagnoses. The interest now is onthe interplay of how a digital resolution choice and variable gain can cope with motion artifactsinherent in mobile health devices. With our methodology for a rapid prototyping of an ECG device,and using the AFE AD8232 and Bluetooth communication, a specific cardiac monitor ECGconfiguration was evaluated under two microcontroller systems of different resolution: a genericArduino Nano board which featured a 10-bit analog-to-digital converter (ADC) and the 24-bit ADCof Silicon Labs C8051F350 board. The ECG cardiac monitor setup, recommended by Analog Devices,featuring two gain values under these two different microcontroller systems, was explored as to itsability to solve motion artifact problems.
简介：In accordance with the big size and bulky volume and not easy to carry of ECG monitoring equipment limitations , a new portable ECG collecting equipment of real-time monitoring andlow-cost was designed. Compared to the static ECG monitor , the new design has obviousadvantages easy to cassy and fit to real-time operate .The device can store 24-hour ECG data andtransfer data with PC through the interface of USB .The ECG waveforms can be displayed in theTFT-LCD real-time and show a good interactive interface .
简介：
In addition to compatibility with VLSI technology, sigma-delta convertersprovide high level of reliability and functionality and reduced chip cost.
Those characteristics are commonly required in the today wirelesscommunication environment. The objective of this paper is to simulate andanalyze the sigma-delta technology which proposed for the implementationin the low-digital-bandwidth voice communication. The results ofsimulation show the superior performance of the converter compared to theperformance of more conventional implementations, such as the deltaconverters. Particularly, this paper is focused on simulation andcomparison betien sigma-delta and delta converters in terms of varyingsignal to noise ratio, distortion ratio and sampling structure. The SigmaDelta Modulator have a salient feature of shaping the noise, such thatnoise reduces from the band of interest resulting in high accuracy incomparison to other converters and high tolerance to non idealities ofanalog circuits. The significant advantage of the method is that conversionof analog signals can be performed by using only a 1-bit ADC and analogsignal processing circuits having a precision that is usually much less thanthe resolution of the overall converter. In this project i have done theanalysis on fifth and sixth order of sigma delta adc’s in regarding withSNR, Node Spectrum Analysis and Integrated Poir noise in MatlabSimulink. Introduction
简介：The optimism of Sir Thomas Lewis and the cautions ofDr. Nadas regarding the electrocardiogram (ECG) remainvalid even in this day of sophisticated echocardiography,Doppler flow analysis, and magnetic resonance imaging.
Although it must be admitted that fine details of cardiacanatomy are now best evaluated with these modern techniques, the ECG is not (and never will be) obsolete. It isstill the quickest, safest, and least expensive diagnostic toolin cardiology and is unparalleled in its ability to registerarrhythmias and conduction defects. With proper interpretation, the ECG also offers a useful reflection of cardiacposition, chamber enlargement, myocardial damage, andcertain metabolic disorders. It has clearly proven its worthafter more than a century of continuous clinical use.
This chapter is intended as a review of electrocardiographyas it applies to the pediatric patient. Rather than simplycatalogue a litany of rules for ECG interpretation, we haveexpanded the discussion here to encompass the basic cellular events underlying cardiac electrical activity, along witha survey of invasive and noninvasive techniques used forin-depth analysis of cardiac rhythm and conduction patterns.
This information is intended not only to clarify the originof ECG signals recorded from the body surface but also toserve as an introduction to the broader topic of cardiacarrhythmias that will be addressed further in Chapter 29 ofthis text.
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The electrocardiogram (ECG) is one of the simplest and oldest cardiac investigations available, yet it canprovide a wealth of useful information and remains an essential part of the assessment of cardiac patients.
With modern machines, surface ECGs are quick and easy to obtain at the bedside and are based on relativelysimple electrophysiological concepts. However junior doctors often find them difficult to interpret.
This is the first in a series of articles that aim to:? Help readers understand and interpret ECG recordings.
? Reduce some of the anxiety juniors often experience when faced with an ECG.
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Introduction Review ECG Basics to increase your knowledge of the electrocardiogram (ECG). In the PALS Provider Course you must be able to identify core rhythms during the case simulations and core case tests. Electrocardiogram Normal Cardiac Cycle The surface ECG is a graphic representation of the sequence of myocardial depolarization and repolarization. Each normal cardiac cycle (Figure 1) consists of a ? P wave ? QRS complex ? T wave Electrical depolarization begins in the sinoatrial node at the junction of the superior vena cava and right atrium and advances through atrial tissue to the atrioventricular (AV) node, where conduction velocity slows temporarily. It then progresses via the bundle of His and the Purkinje system to depolarize the ventricular myocardium (Figure 2). The first deflection on the surface ECG (P wave) represents depolarization of both atria. The time required for depolarization to pass through the atria, the AV node, and the His-Purkinje system is represented by the PR interval. The QRS complex represents depolarization of the ventricular myocardium. Ventricular repolarization is characterized on the surface ECG as the ST segment and T wave (Figure 3). Figure 1. The electrocardiogram
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This work demonstrates for the first time the implementation of a level-crossing analog-to-digital converter (LC-ADC)in a single, commercially available IC (that costs less than $2). The implementation utilizes adaptive threshold levelsin order to prevent overload distortions for fast-changing signals. The entire design is based on a 20-pin PIC16F1769microcontroller from Microchip and no external components are required. In fact, the only external circuitry required is asingle jumper wire. This is due to the fact that the new generation of microcontrollers have integrated core-independenthardware, analog as well as digital. This design takes full advantage of the core-independent logic and analog blocksin a PIC16F17xx circuit to implement the LC-ADC technique that so far has required multiple-circuit designs or ASICimplementation. The design is demonstrated on a standard electrocardiogram (ECG) signal.
简介：Identify the conduction system of the heart and the components of the cardiac cycleDiscuss a systematic approach to rhythm interpretationReview common cardiac arrhythmiasDescribe the process for interpretation of a 12 lead ECG
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