2021 XXX International Scientific Conference Electronics (ET), 2021
This paper presents the design of an analogue ECG front-end applicable for non-contact registrati... more This paper presents the design of an analogue ECG front-end applicable for non-contact registration of cardiac activity using capacitive electrodes. While common instrumental amplifiers with such an application require extremely high input resistance, the proposed implementation is based on transimpedance amplifiers, allowing for a multifold reduction of the input resistance. The results of the LTSpice analysis show that the low cutoff frequency is 0.2 Hz (bellow than standard 0.5 Hz) as well as there is no distortion in the high frequency range, even when amplifying pacemaker pulses with approximately rectangular shape.
2021 XXX International Scientific Conference Electronics (ET), 2021
The monitoring of the cardiac activity in the everyday life is becoming increasingly more popular... more The monitoring of the cardiac activity in the everyday life is becoming increasingly more popular. For this purpose a novel type capacitive electrodes which do not require direct skin contact or wetting with electrolyte are preferred. This new type of electrodes usually requires extremely high input impedance. This study aims to present the development of an input buffer interfacing with capacitive electrodes. The developed buffer will give the opportunity to build ECG acquisition system with non-contact capacitive electrodes for rhythm detection for patients at risk recovering in their natural living environment.
2020 XXIX International Scientific Conference Electronics (ET), 2020
As is known the plasma treatment inactivates microbial pathogens, mainly bacteria, fungi, and vir... more As is known the plasma treatment inactivates microbial pathogens, mainly bacteria, fungi, and viruses and is widely used for sterilization of medical and dental devices, as well as agricultural products. This article reviews the existing problems connected with the disinfection/sterilization of heat-sensitive biomaterials and structures as: skin, wounds, meat animal products, etc. The design of a new type low-temperature plasma disinfection/sterilization accessory featuring small size and easy usability is presented. The achieved results at initial tests are evaluated in the context of applicability for sterilization procedures in medical practice.
International Journal of Advanced Computer Research, 2014
Ambient Assisted Living (AAL) systems are a relatively new and expanding area of research. Due to... more Ambient Assisted Living (AAL) systems are a relatively new and expanding area of research. Due to current demographic trends towards gentrification of the population AAL systems are bound to become more important in todays and near future's societies. Fall detection is an important component of AAL systems which could provide better safety and higher independency of the elderly. This paper presents a survey on automatic fall detection in the context of AAL systems. Keywords : Ambient assisted living, fall detection, accelerometers, computer vision, comparative study. Issues of this journal are numbered consecutively. This article appeared in #14. Language: en
"This paper presents a linear phase comb filter for power-line interference suppression.... more "This paper presents a linear phase comb filter for power-line interference suppression. By a correlated average using samples delayed on multiple power-line periods, and subtracting the result from the input stream, a high-pass comb filter with high-Q notches at all power-line harmonics is attained. The high-pass roll-off of the filter is compensated with appropriate low-pass roll-off, and the resultant characteristic has an all-pass (flat) frequency response and notches only at the power-line harmonics. The filter design is based on a high-pass high-Q comb filter, in parallel with a low-pass moving-average stage to restore the low-frequency filtered components. The Q-factor depends on the time for averaging. The presented filter is evaluated by Matlab simulations with real ECG signal contaminated with high amplitude power-line interference. The simulations show that this filter has minimal influence on the processed ECG signal. Due to the filter’s constant group delay (linear phase response) and high-Q notches only at the power-line harmonics, the presented filter is appropriate for power-line rejection in almost all biosignal acquisition applications. The filter is applicable for real-time execution by means of conventional low-cost microcontrollers."
The development of accurate and fast methods for real-time electrocardiogram (ECG) analysis is ma... more The development of accurate and fast methods for real-time electrocardiogram (ECG) analysis is mandatory in handheld fully automated monitoring devices for high-risk cardiac patients. The present work describes a simple software method for fast detection of pathological cardiac events. It implements real-time procedures for QRS detection, interbeat RR-intervals analysis, QRS waveform evaluation and a decision-tree beat classifier. Two QRS descriptors are defined to assess (i) the RR interval deviation from the mean RR interval and (ii) the QRS waveform deviation from the QRS pattern of the sustained rhythm. The calculation of the second parameter requires a specific technique, in order to satisfy the demand for straight signal processing with minimum iterations and small memory size. This technique includes fast and resource efficient estimation of a histogram matrix, which accumulates dynamically the amplitude-temporal distribution of the successive QRS pattern waveforms. The pilot version of the method is developed in Matlab and it is tested with internationally recognized ECG databases. The assessment of the online single lead QRS detector showed sensitivity and positive predictivity of above 99%. The classification rules for detection of pathological ventricular beats were defined empirically by statistical analysis. The attained specificity and sensitivity are about 99.5% and 95.7% for all databases and about 99.81% and 98.87% for the noise free dataset. The method is applicable in low computational cost systems for long-term ECG monitoring, such as intelligent holters, automatic event/alarm recorders or personal devices with intermittent wireless data transfer to a central terminal.
This paper presents an ECG database, named 'PacedECGdb' (available at http://biomed.bas.b... more This paper presents an ECG database, named 'PacedECGdb' (available at http://biomed.bas.bg/bioautomation/2014/vol_18.4/files/PacedECGdb.zip), which contains different arrhythmias generated by HKP (Heidelberger Praxisklinik) simulator, combined with artificially superimposed pacing pulses that cover the wide ranges of rising edge (from <10 µs to 100 µs) and total pulse durations (from 100 µs to 2 ms) and correspond to various pacemaker modes. It involves a total number of 1404 recordings - 780 representing 'pure' ECG with pacing pulses and 624 that comprise paced ECGs corrupted by tremor. The signals are recorded with 9.81 µV/LSB amplitude resolution at 128 kHz sampling rate in order to preserve the steep raising and trailing edges of the pace pulses. To the best of our knowledge, 'PacedECGdb' is the first publicly available paced ECG database. It could be used for development and testing of methods for pace detection in the ECG. The existence of ECGs corru...
2017 XXVI International Scientific Conference Electronics (ET), 2017
Modern communication technologies allow significant extension of the ambulatory monitoring of ris... more Modern communication technologies allow significant extension of the ambulatory monitoring of risk patients. The practice shows that one of the most common causes for remote monitoring compromise is the lack of skills for use of the equipment. An alternative representation of ECG is investigated in this paper. The aim is to provide an innovative approach for ECG transmission on long distance using a simple GSM module working in standard voice communication mode. The proposed procedure — "sonification" is tested with signals recorded from patients with cardiostimulator. Our experiments confirmed reliability of data processing and signal presentation with quality guarantying the correctness of medical conclusions.
This paper reviews some different methods for detecting the pulses created by an implanted cardia... more This paper reviews some different methods for detecting the pulses created by an implanted cardiac pacemaker in the ECG signal. It includes a hardware method implemented in a Texas Instruments circuit, software method proposed by Herleikson and patented by Hewlett-Packard, an upgrade of Herleikson’s algorithm reported by Polpetta and Banelli and an software pace pulse detection embedded in the analog front end module of Analog Devices – ADAS1000.
A pacemaker is a small battery-operated medical device that delivers electrical impulses to the h... more A pacemaker is a small battery-operated medical device that delivers electrical impulses to the heart in order to guarantee regular contractions. Depending on the number of active leads the pacemakers are single chamber, dual chamber and bi-ventricular. According to their programming the devices could be with fixed-rate, 'on demand' and rate- responsitive. The operating mode of the pacemaker depends on the paced chamber, the sensed chamber, the response to a sensed electrical signal and the rate modulation. Two types of pacing are recognized - unipolar and bipolar, represented with different pacing artifacts in the ECG signal. The pacing pulse on the skin surface usually have very fast rising edges of the order of 10 µs or less and could be as small as few hundreds µV. The pacing artifacts detection is important since they indicate the presence of a pacemaker and help to evaluate the reaction of the heart. All pertinent medical standards require the pacing artifacts to be ca...
2020 XI National Conference with International Participation (ELECTRONICA), 2020
The remote patient monitoring system has become a research hotspot in recent years. Using ICT and... more The remote patient monitoring system has become a research hotspot in recent years. Using ICT and wearable technology, it is possible to monitor the user's health condition in real-time. At the same time, the development of communication technologies with higher density of the communication channels is associated with increasingly occurring collisions. A simple approach using a mobile phone (GSM) for patient's data transmission of audio transformed biological signals is discussed in this paper. The results of the performed experimental laboratory tests for determining the acoustic characteristics of GSM devices are presented.
Normally innervated muscles are stimulated to contraction through peripheral motor nerves and esp... more Normally innervated muscles are stimulated to contraction through peripheral motor nerves and especially the intra-muscular innervating nerve fibbers. Various stimuli parameters can be used for non-denervated muscle stimulation, depending on the specific treatment. In difference with well-known applications used low frequency currents in the range 10-100Hz, the new devices for electrical stimulation are base on middle frequency range 2000-8000Hz modulated by low frequency. The middle frequency allows overcome the patient resistance and therapeutic treatment in depth. Taking into account the advantages of Class-D amplifiers we suggest new solution based on the specialized circuit ZXCD1000 by ZETEX. This solution considerably facilitates the development process. One circuit is used to realize two independent channels. The therapeutic energy transfers to the patient via highfrequency transformers with small sizes. In addition the selected circuit guarantees convenience and flexibility ...
2021 XXX International Scientific Conference Electronics (ET), 2021
This paper presents the design of an analogue ECG front-end applicable for non-contact registrati... more This paper presents the design of an analogue ECG front-end applicable for non-contact registration of cardiac activity using capacitive electrodes. While common instrumental amplifiers with such an application require extremely high input resistance, the proposed implementation is based on transimpedance amplifiers, allowing for a multifold reduction of the input resistance. The results of the LTSpice analysis show that the low cutoff frequency is 0.2 Hz (bellow than standard 0.5 Hz) as well as there is no distortion in the high frequency range, even when amplifying pacemaker pulses with approximately rectangular shape.
2021 XXX International Scientific Conference Electronics (ET), 2021
The monitoring of the cardiac activity in the everyday life is becoming increasingly more popular... more The monitoring of the cardiac activity in the everyday life is becoming increasingly more popular. For this purpose a novel type capacitive electrodes which do not require direct skin contact or wetting with electrolyte are preferred. This new type of electrodes usually requires extremely high input impedance. This study aims to present the development of an input buffer interfacing with capacitive electrodes. The developed buffer will give the opportunity to build ECG acquisition system with non-contact capacitive electrodes for rhythm detection for patients at risk recovering in their natural living environment.
2020 XXIX International Scientific Conference Electronics (ET), 2020
As is known the plasma treatment inactivates microbial pathogens, mainly bacteria, fungi, and vir... more As is known the plasma treatment inactivates microbial pathogens, mainly bacteria, fungi, and viruses and is widely used for sterilization of medical and dental devices, as well as agricultural products. This article reviews the existing problems connected with the disinfection/sterilization of heat-sensitive biomaterials and structures as: skin, wounds, meat animal products, etc. The design of a new type low-temperature plasma disinfection/sterilization accessory featuring small size and easy usability is presented. The achieved results at initial tests are evaluated in the context of applicability for sterilization procedures in medical practice.
International Journal of Advanced Computer Research, 2014
Ambient Assisted Living (AAL) systems are a relatively new and expanding area of research. Due to... more Ambient Assisted Living (AAL) systems are a relatively new and expanding area of research. Due to current demographic trends towards gentrification of the population AAL systems are bound to become more important in todays and near future's societies. Fall detection is an important component of AAL systems which could provide better safety and higher independency of the elderly. This paper presents a survey on automatic fall detection in the context of AAL systems. Keywords : Ambient assisted living, fall detection, accelerometers, computer vision, comparative study. Issues of this journal are numbered consecutively. This article appeared in #14. Language: en
&quot;This paper presents a linear phase comb filter for power-line interference suppression.... more &quot;This paper presents a linear phase comb filter for power-line interference suppression. By a correlated average using samples delayed on multiple power-line periods, and subtracting the result from the input stream, a high-pass comb filter with high-Q notches at all power-line harmonics is attained. The high-pass roll-off of the filter is compensated with appropriate low-pass roll-off, and the resultant characteristic has an all-pass (flat) frequency response and notches only at the power-line harmonics. The filter design is based on a high-pass high-Q comb filter, in parallel with a low-pass moving-average stage to restore the low-frequency filtered components. The Q-factor depends on the time for averaging. The presented filter is evaluated by Matlab simulations with real ECG signal contaminated with high amplitude power-line interference. The simulations show that this filter has minimal influence on the processed ECG signal. Due to the filter’s constant group delay (linear phase response) and high-Q notches only at the power-line harmonics, the presented filter is appropriate for power-line rejection in almost all biosignal acquisition applications. The filter is applicable for real-time execution by means of conventional low-cost microcontrollers.&quot;
The development of accurate and fast methods for real-time electrocardiogram (ECG) analysis is ma... more The development of accurate and fast methods for real-time electrocardiogram (ECG) analysis is mandatory in handheld fully automated monitoring devices for high-risk cardiac patients. The present work describes a simple software method for fast detection of pathological cardiac events. It implements real-time procedures for QRS detection, interbeat RR-intervals analysis, QRS waveform evaluation and a decision-tree beat classifier. Two QRS descriptors are defined to assess (i) the RR interval deviation from the mean RR interval and (ii) the QRS waveform deviation from the QRS pattern of the sustained rhythm. The calculation of the second parameter requires a specific technique, in order to satisfy the demand for straight signal processing with minimum iterations and small memory size. This technique includes fast and resource efficient estimation of a histogram matrix, which accumulates dynamically the amplitude-temporal distribution of the successive QRS pattern waveforms. The pilot version of the method is developed in Matlab and it is tested with internationally recognized ECG databases. The assessment of the online single lead QRS detector showed sensitivity and positive predictivity of above 99%. The classification rules for detection of pathological ventricular beats were defined empirically by statistical analysis. The attained specificity and sensitivity are about 99.5% and 95.7% for all databases and about 99.81% and 98.87% for the noise free dataset. The method is applicable in low computational cost systems for long-term ECG monitoring, such as intelligent holters, automatic event/alarm recorders or personal devices with intermittent wireless data transfer to a central terminal.
This paper presents an ECG database, named 'PacedECGdb' (available at http://biomed.bas.b... more This paper presents an ECG database, named 'PacedECGdb' (available at http://biomed.bas.bg/bioautomation/2014/vol_18.4/files/PacedECGdb.zip), which contains different arrhythmias generated by HKP (Heidelberger Praxisklinik) simulator, combined with artificially superimposed pacing pulses that cover the wide ranges of rising edge (from <10 µs to 100 µs) and total pulse durations (from 100 µs to 2 ms) and correspond to various pacemaker modes. It involves a total number of 1404 recordings - 780 representing 'pure' ECG with pacing pulses and 624 that comprise paced ECGs corrupted by tremor. The signals are recorded with 9.81 µV/LSB amplitude resolution at 128 kHz sampling rate in order to preserve the steep raising and trailing edges of the pace pulses. To the best of our knowledge, 'PacedECGdb' is the first publicly available paced ECG database. It could be used for development and testing of methods for pace detection in the ECG. The existence of ECGs corru...
2017 XXVI International Scientific Conference Electronics (ET), 2017
Modern communication technologies allow significant extension of the ambulatory monitoring of ris... more Modern communication technologies allow significant extension of the ambulatory monitoring of risk patients. The practice shows that one of the most common causes for remote monitoring compromise is the lack of skills for use of the equipment. An alternative representation of ECG is investigated in this paper. The aim is to provide an innovative approach for ECG transmission on long distance using a simple GSM module working in standard voice communication mode. The proposed procedure — "sonification" is tested with signals recorded from patients with cardiostimulator. Our experiments confirmed reliability of data processing and signal presentation with quality guarantying the correctness of medical conclusions.
This paper reviews some different methods for detecting the pulses created by an implanted cardia... more This paper reviews some different methods for detecting the pulses created by an implanted cardiac pacemaker in the ECG signal. It includes a hardware method implemented in a Texas Instruments circuit, software method proposed by Herleikson and patented by Hewlett-Packard, an upgrade of Herleikson’s algorithm reported by Polpetta and Banelli and an software pace pulse detection embedded in the analog front end module of Analog Devices – ADAS1000.
A pacemaker is a small battery-operated medical device that delivers electrical impulses to the h... more A pacemaker is a small battery-operated medical device that delivers electrical impulses to the heart in order to guarantee regular contractions. Depending on the number of active leads the pacemakers are single chamber, dual chamber and bi-ventricular. According to their programming the devices could be with fixed-rate, 'on demand' and rate- responsitive. The operating mode of the pacemaker depends on the paced chamber, the sensed chamber, the response to a sensed electrical signal and the rate modulation. Two types of pacing are recognized - unipolar and bipolar, represented with different pacing artifacts in the ECG signal. The pacing pulse on the skin surface usually have very fast rising edges of the order of 10 µs or less and could be as small as few hundreds µV. The pacing artifacts detection is important since they indicate the presence of a pacemaker and help to evaluate the reaction of the heart. All pertinent medical standards require the pacing artifacts to be ca...
2020 XI National Conference with International Participation (ELECTRONICA), 2020
The remote patient monitoring system has become a research hotspot in recent years. Using ICT and... more The remote patient monitoring system has become a research hotspot in recent years. Using ICT and wearable technology, it is possible to monitor the user's health condition in real-time. At the same time, the development of communication technologies with higher density of the communication channels is associated with increasingly occurring collisions. A simple approach using a mobile phone (GSM) for patient's data transmission of audio transformed biological signals is discussed in this paper. The results of the performed experimental laboratory tests for determining the acoustic characteristics of GSM devices are presented.
Normally innervated muscles are stimulated to contraction through peripheral motor nerves and esp... more Normally innervated muscles are stimulated to contraction through peripheral motor nerves and especially the intra-muscular innervating nerve fibbers. Various stimuli parameters can be used for non-denervated muscle stimulation, depending on the specific treatment. In difference with well-known applications used low frequency currents in the range 10-100Hz, the new devices for electrical stimulation are base on middle frequency range 2000-8000Hz modulated by low frequency. The middle frequency allows overcome the patient resistance and therapeutic treatment in depth. Taking into account the advantages of Class-D amplifiers we suggest new solution based on the specialized circuit ZXCD1000 by ZETEX. This solution considerably facilitates the development process. One circuit is used to realize two independent channels. The therapeutic energy transfers to the patient via highfrequency transformers with small sizes. In addition the selected circuit guarantees convenience and flexibility ...
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