The Experts below are selected from a list of 1800 Experts worldwide ranked by ideXlab platform
Enrique Mario Spinelli - One of the best experts on this subject based on the ideXlab platform.
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a practical approach to electrode skin impedance unbalance measurement
IEEE Transactions on Biomedical Engineering, 2006Co-Authors: Enrique Mario Spinelli, Miguel Angel Mayosky, R PallasarenyAbstract:Unbalance between electrode-skin impedances is a major problem in Biopotential recordings, leading to increased power-line interference. This paper proposes a simple, direct method to measure that unbalance at power-line frequency (50-60 Hz), thus allowing the determination of actual recording conditions for Biopotential amplifiers. The method is useful in research, amplifier testing, electrode design and teaching purposes. It has been experimentally validated by using both phantom impedances and real electrode-skin impedances.
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a novel fully differential Biopotential amplifier with dc suppression
IEEE Transactions on Biomedical Engineering, 2004Co-Authors: Enrique Mario Spinelli, Miguel Angel Mayosky, N Martinez, R PallasarenyAbstract:Fully differential amplifiers yield large differential gains and also high common mode rejection ratio (CMRR), provided they do not include any unmatched grounded component. In Biopotential measurements, however, the admissible gain of amplification stages located before dc suppression is usually limited by electrode offset voltage, which can saturate amplifier outputs. The standard solution is to first convert the differential input voltage to a single-ended voltage and then implement any other required functions, such as dc suppression and dc level restoring. This approach, however, yields a limited CMRR and may result in a relatively large equivalent input noise. This paper describes a novel fully differential Biopotential amplifier based on a fully differential dc-suppression circuit that does not rely on any matched passive components, yet provides large CMRR and fast recovery from dc level transients. The proposed solution is particularly convenient for low supply voltage systems. An example implementation, based on standard low-power op amps and a single 5-V power supply, accepts input offset voltages up to /spl plusmn/500 mV, yields a CMRR of 102dB at 50 Hz, and provides, in accordance with the AAMI EC38 standard, a reset behavior for recovering from overloads or artifacts.
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AC-coupled front-end for Biopotential measurements
IEEE Transactions on Biomedical Engineering, 2003Co-Authors: Enrique Mario Spinelli, Ramon Pallas-areny, Miguel Angel MayoskyAbstract:AC coupling is essential in Biopotential measurements. Electrode offset potentials can be several orders of magnitude larger than the amplitudes of the biological signals of interest, thus limiting the admissible gain of a dc-coupled front end to prevent amplifier saturation. A high-gain input stage needs ac input coupling. This can be achieved by series capacitors, but in order to provide a bias path, grounded resistors are usually included, which degrade the common mode rejection ratio (CMRR). This paper proposes a novel balanced input ac-coupling network that provides a bias path without any connection to ground, thus resulting in a high CMRR. The circuit being passive, it does not limit the differential dc input voltage. Furthermore, differential signals are ac coupled, whereas common-mode voltages are dc coupled, thus allowing the closed-loop control of the dc common mode voltage by means of a driven-right-leg circuit. This makes the circuit compatible with common-mode dc shifting strategies intended for single-supply Biopotential amplifiers. The proposed circuit allows the implementation of high-gain Biopotential amplifiers with a reduced number of parts, thus resulting in low power consumption. An electrocardiogram amplifier built according to the proposed design achieves a CMRR of 123 dB at 50 Hz.
Miguel Angel Mayosky - One of the best experts on this subject based on the ideXlab platform.
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a practical approach to electrode skin impedance unbalance measurement
IEEE Transactions on Biomedical Engineering, 2006Co-Authors: Enrique Mario Spinelli, Miguel Angel Mayosky, R PallasarenyAbstract:Unbalance between electrode-skin impedances is a major problem in Biopotential recordings, leading to increased power-line interference. This paper proposes a simple, direct method to measure that unbalance at power-line frequency (50-60 Hz), thus allowing the determination of actual recording conditions for Biopotential amplifiers. The method is useful in research, amplifier testing, electrode design and teaching purposes. It has been experimentally validated by using both phantom impedances and real electrode-skin impedances.
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a novel fully differential Biopotential amplifier with dc suppression
IEEE Transactions on Biomedical Engineering, 2004Co-Authors: Enrique Mario Spinelli, Miguel Angel Mayosky, N Martinez, R PallasarenyAbstract:Fully differential amplifiers yield large differential gains and also high common mode rejection ratio (CMRR), provided they do not include any unmatched grounded component. In Biopotential measurements, however, the admissible gain of amplification stages located before dc suppression is usually limited by electrode offset voltage, which can saturate amplifier outputs. The standard solution is to first convert the differential input voltage to a single-ended voltage and then implement any other required functions, such as dc suppression and dc level restoring. This approach, however, yields a limited CMRR and may result in a relatively large equivalent input noise. This paper describes a novel fully differential Biopotential amplifier based on a fully differential dc-suppression circuit that does not rely on any matched passive components, yet provides large CMRR and fast recovery from dc level transients. The proposed solution is particularly convenient for low supply voltage systems. An example implementation, based on standard low-power op amps and a single 5-V power supply, accepts input offset voltages up to /spl plusmn/500 mV, yields a CMRR of 102dB at 50 Hz, and provides, in accordance with the AAMI EC38 standard, a reset behavior for recovering from overloads or artifacts.
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AC-coupled front-end for Biopotential measurements
IEEE Transactions on Biomedical Engineering, 2003Co-Authors: Enrique Mario Spinelli, Ramon Pallas-areny, Miguel Angel MayoskyAbstract:AC coupling is essential in Biopotential measurements. Electrode offset potentials can be several orders of magnitude larger than the amplitudes of the biological signals of interest, thus limiting the admissible gain of a dc-coupled front end to prevent amplifier saturation. A high-gain input stage needs ac input coupling. This can be achieved by series capacitors, but in order to provide a bias path, grounded resistors are usually included, which degrade the common mode rejection ratio (CMRR). This paper proposes a novel balanced input ac-coupling network that provides a bias path without any connection to ground, thus resulting in a high CMRR. The circuit being passive, it does not limit the differential dc input voltage. Furthermore, differential signals are ac coupled, whereas common-mode voltages are dc coupled, thus allowing the closed-loop control of the dc common mode voltage by means of a driven-right-leg circuit. This makes the circuit compatible with common-mode dc shifting strategies intended for single-supply Biopotential amplifiers. The proposed circuit allows the implementation of high-gain Biopotential amplifiers with a reduced number of parts, thus resulting in low power consumption. An electrocardiogram amplifier built according to the proposed design achieves a CMRR of 123 dB at 50 Hz.
Refet Firat Yazicioglu - One of the best experts on this subject based on the ideXlab platform.
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24 7 a 60nv hz 15 channel digital active electrode system for portable Biopotential signal acquisition
International Solid-State Circuits Conference, 2014Co-Authors: Benjamin Busze, Chris Van Hoof, Hyejung Kim, Kofi A A Makinwa, Refet Firat YaziciogluAbstract:Dry active electrodes (AE), i.e., the combination of dry electrodes with in situ amplification, are increasingly used for Biopotential measurements in emerging healthcare and lifestyle applications [1]. Compared to gel-based wet electrodes, dry electrodes enable fast set-up time, greater user comfort, and long-term monitoring. AE amplifiers ensure local amplification providing improved robustness to noise interference and cable motion artifacts. However, current AEs have analog outputs requiring powerful analog buffers to drive Biopotential signals over measurement cables. Furthermore, analog outputs must be digitized by the back-end (BE) system [2,3]. Besides, parameter mismatch between AEs limits the overall CMRR. CMFB [1] or CMFF [2] helps but comes at the expense of increased number cables between the BE and AEs. These problems significantly increase the overall system complexity and cost.
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24 7 a 60nv hz 15 channel digital active electrode system for portable Biopotential signal acquisition
International Solid-State Circuits Conference, 2014Co-Authors: Jiawei Xu, Kofi A A Makinwa, Benjamin Busze, Chris Van Hoof, Refet Firat YaziciogluAbstract:Dry active electrodes (AE), i.e., the combination of dry electrodes with in situ amplification, are increasingly used for Biopotential measurements in emerging healthcare and lifestyle applications [1]. Compared to gel-based wet electrodes, dry electrodes enable fast set-up time, greater user comfort, and long-term monitoring. AE amplifiers ensure local amplification providing improved robustness to noise interference and cable motion artifacts. However, current AEs have analog outputs requiring powerful analog buffers to drive Biopotential signals over measurement cables. Furthermore, analog outputs must be digitized by the back-end (BE) system [2,3]. Besides, parameter mismatch between AEs limits the overall CMRR. CMFB [1] or CMFF [2] helps but comes at the expense of increased number cables between the BE and AEs. These problems significantly increase the overall system complexity and cost.
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A 160μW 8-channel active electrode system for EEG monitoring
2011 IEEE International Solid-State Circuits Conference, 2011Co-Authors: Jiawei Xu, Refet Firat Yazicioglu, Kofi A A Makinwa, Pieter Harpe, Chris Van HoofAbstract:An important drawback of current Biopotential monitoring systems is their dependence on gel electrodes, which can dry out, cause skin irritation, and necessitate skilled personnel. These associated drawbacks increase the running costs and significantly hamper their use in consumer healthcare and lifestyle applications. Unfortunately, the use of gel-free, or dry, electrodes increases the electrode-tissue contact impedance, thus exacerbating the effects of interference and cable motion artifacts. A solution is the use of active electrodes, i.e. electrodes in which an amplifier with high input impedance, low noise and good electrode offset rejection is co-integrated. Previous active electrodes employed voltage buffers to facilitate the inter-channel gain matching necessary to achieve high CMRR. However, low-noise buffers consume significant power and due to their lack of gain still require a low-noise and thus power-hungry back-end to keep the total integrated noise at acceptable levels. To reduce the total power dissipation, this paper proposes a Biopotential monitoring system based on active electrodes with gain.
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a 200 mu w eight channel eeg acquisition asic for ambulatory eeg systems
IEEE Journal of Solid-state Circuits, 2008Co-Authors: Refet Firat Yazicioglu, Patrick Merken, Robert Puers, C Van HoofAbstract:The growing interest toward the improvement of patients' quality of life and the use of medical signals in nonmedical applications such as entertainment, sports, and brain-computerinterfaces, requires the implementation of miniaturized and wireless Biopotential acquisition systems with ultralow power dissipation. Therefore, this paper presents the implementation of a complete EEG acquisition ASIC tailored towards the needs of such applications, i.e., high-signal quality, low-power dissipation and ease of use. The presented ASIC includes eight readout front-end channels and an 11-bit analog-to-digital converter (ADC). The key to its high performance and low-power dissipation is the new AC coupled chopper stabilized instrumentation amplifier (ACCIA) implementation that uses a coarse-fine servoloop and reaches more than 120 dB CMRR, consumes only 2.3 muA , and achieves a noise-efficiency factor (NEF) of 4.3. Furthermore, the ease of use of the ASIC is realized by incorporating Calibration and Electrode Impedance Measurement Modes to the ASIC. Therefore, the former can be used to check the functionality of the ASIC, as well as, to calibrate the gain matching of the channels, where as the latter can be used to track the quality of the Biopotential electrode. The ASIC is implemented in 0.5 mum CMOS process and the total current consumption is 66 muA from 3 V.
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a 200μw eight channel acquisition asic for ambulatory eeg systems
International Solid-State Circuits Conference, 2008Co-Authors: Refet Firat Yazicioglu, Patrick Merken, Robert Puers, C Van HoofAbstract:A crucial and important part of a medical diagnostics system is the monitoring of the Biopotential signals. This paper describes a complete low-power EEG acquisition ASIC that is suitable for miniaturized ambulatory EEG measurement systems. The aim is not only to improve the patients' comfort but also to extend the device applications.
R Pallasareny - One of the best experts on this subject based on the ideXlab platform.
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a practical approach to electrode skin impedance unbalance measurement
IEEE Transactions on Biomedical Engineering, 2006Co-Authors: Enrique Mario Spinelli, Miguel Angel Mayosky, R PallasarenyAbstract:Unbalance between electrode-skin impedances is a major problem in Biopotential recordings, leading to increased power-line interference. This paper proposes a simple, direct method to measure that unbalance at power-line frequency (50-60 Hz), thus allowing the determination of actual recording conditions for Biopotential amplifiers. The method is useful in research, amplifier testing, electrode design and teaching purposes. It has been experimentally validated by using both phantom impedances and real electrode-skin impedances.
-
a novel fully differential Biopotential amplifier with dc suppression
IEEE Transactions on Biomedical Engineering, 2004Co-Authors: Enrique Mario Spinelli, Miguel Angel Mayosky, N Martinez, R PallasarenyAbstract:Fully differential amplifiers yield large differential gains and also high common mode rejection ratio (CMRR), provided they do not include any unmatched grounded component. In Biopotential measurements, however, the admissible gain of amplification stages located before dc suppression is usually limited by electrode offset voltage, which can saturate amplifier outputs. The standard solution is to first convert the differential input voltage to a single-ended voltage and then implement any other required functions, such as dc suppression and dc level restoring. This approach, however, yields a limited CMRR and may result in a relatively large equivalent input noise. This paper describes a novel fully differential Biopotential amplifier based on a fully differential dc-suppression circuit that does not rely on any matched passive components, yet provides large CMRR and fast recovery from dc level transients. The proposed solution is particularly convenient for low supply voltage systems. An example implementation, based on standard low-power op amps and a single 5-V power supply, accepts input offset voltages up to /spl plusmn/500 mV, yields a CMRR of 102dB at 50 Hz, and provides, in accordance with the AAMI EC38 standard, a reset behavior for recovering from overloads or artifacts.
Shreyas Sen - One of the best experts on this subject based on the ideXlab platform.
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electro quasistatic animal body communication for untethered rodent Biopotential recording
Scientific Reports, 2021Co-Authors: Shreeya Sriram, Shitij Avlani, Matthew P Ward, Shreyas SenAbstract:Continuous multi-channel monitoring of Biopotential signals is vital in understanding the body as a whole, facilitating accurate models and predictions in neural research. The current state of the art in wireless technologies for untethered Biopotential recordings rely on radiative electromagnetic (EM) fields. In such transmissions, only a small fraction of this energy is received since the EM fields are widely radiated resulting in lossy inefficient systems. Using the body as a communication medium (similar to a ’wire’) allows for the containment of the energy within the body, yielding order(s) of magnitude lower energy than radiative EM communication. In this work, we introduce Animal Body Communication (ABC), which utilizes the concept of using the body as a medium into the domain of untethered animal Biopotential recording. This work, for the first time, develops the theory and models for animal body communication circuitry and channel loss. Using this theoretical model, a sub-inch $$^3$$ [1″ × 1″ × 0.4″], custom-designed sensor node is built using off the shelf components which is capable of sensing and transmitting Biopotential signals, through the body of the rat at significantly lower powers compared to traditional wireless transmissions. In-vivo experimental analysis proves that ABC successfully transmits acquired electrocardiogram (EKG) signals through the body with correlation $$>99\%$$ when compared to traditional wireless communication modalities, with a 50 $$\times$$ reduction in power consumption.