scholarly journals True Unipolar ECG Machine for Wilson Central Terminal Measurements

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Gaetano D. Gargiulo
Keyword(s):  
Medical Practice ◽  
Cardiac Cycle ◽  
Reference Voltage ◽  
Voltage Reference ◽  
Research Attention ◽  
And Behavior ◽  
Central Terminal ◽  
Stable Voltage ◽  
Four Electrodes

Since its invention (more than 80 years ago), modern electrocardiography has employed a supposedly stable voltage reference (with little variation during the cardiac cycle) for half of the signals. This reference, known by the name of “Wilson Central Terminal” in honor of its inventor, is obtained by averaging the three active limb electrode voltages measured with respect to the return ground electrode. However, concerns have been raised by researchers about problems (biasing and misdiagnosis) associated with the ambiguous value and behavior of this reference voltage, which requires perfect and balanced contact of at least four electrodes to work properly. The Wilson Central Terminal has received scant research attention in the last few decades even though consideration of recent widespread medical practice (limb electrodes are repositioned closer to the torso for resting electrocardiography) has also sparkled concerns about the validity and diagnostic fitness of leads not referred to the Wilson Central Terminal. Using a true unipolar electrocardiography device capable of precisely measuring the Wilson Central Terminal, we show its unpredictable variability during the cardiac cycle and confirm that the integrity of cardinal leads is compromised as well as the Wilson Central Terminal when limb electrodes are placed close to the torso.

A High Temperature 4H-SiC Voltage Reference for Depletion Mode GaN-Based Circuits

2017 ◽  
Vol 2017 (HiTEN) ◽  
pp. 000118-000121
Author(s):  
ZiHao Zhang ◽  
Jebreel M. Salem ◽  
Dong Sam Ha
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Oil And Gas ◽  
Supply Voltage ◽  
Reference Voltage ◽  
Voltage Reference ◽  
Voltage Range ◽  
Oil And Gas Exploration ◽  
Low Leakage ◽  
Temperature Applications

Abstract High temperature electronics are highly demanded for many applications such as automotive, space, and oil and gas exploration. Electronic circuits for those applications are required to operate reliably without using bulky cooling systems. Circuits based on silicon (Si) suffer from high leakage currents at high temperatures. Silicon Carbide (SiC) circuits, on the other hand, are suitable for high temperature applications due to the wide bandgap and offer high breakdown voltage and low leakage current. This paper presents a negative voltage reference for high temperature applications using commercial-off-the-shelf (COTS) 4H-SiC transistors. The proposed voltage reference adopts Widlar bandgap reference topology, and it aims to provide a negative reference voltage for Gallium Nitride (GaN) circuits operating at high temperatures. Measurement results indicate that the proposed circuit provides a negative reference voltage with a low temperature coefficient of 42 ppm/°C for temperatures ranging from 25 °C to 250 °C. The proposed circuit also operates reliably for a wide supply voltage range of −7.5 V to −15 V for the temperature range.

Design of a High Performance CMOS Bandgap Voltage Reference

2014 ◽  
Vol 981 ◽  
pp. 90-93
Author(s):  
Yang Guang ◽  
Bin Yu ◽  
Huang Hai
Keyword(s):  
Integrated Circuits ◽  
High Performance ◽  
Circuit Simulation ◽  
Absolute Temperature ◽  
Reference Voltage ◽  
Cmos Process ◽  
Voltage Reference ◽  
Temperature Changes ◽  
Bandgap Voltage Reference ◽  
Protection Circuit

Bandgap voltage reference, to provide a temperature and power supply insensitive output voltage, is a very important module in the analog integrated circuits and mixed-signal integrated circuits. In this paper, a high performance CMOS bandgap with low-power consumption has been designed. It can get the PTAT (Proportional to absolute temperature) current, and then get the reference voltage. Based on 0.35μm CMOS process, using HSPICE 2008 software for circuit simulation, the results showed that , when the temperature changes from -40 to 80 °C, the proposed circuit’s reference voltage achieve to 1.2V, temperature coefficient is 3.09ppm/°C. Adopt a series of measures, like ESD protection circuit, in layout design. The ultimately design through the DRC and LVS verification, and the final layout size is 700μm * 560μm.

scholarly journals On the Einthoven Triangle: A Critical Analysis of the Single Rotating Dipole Hypothesis

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2353 ◽  
Author(s):  
Gaetano Gargiulo ◽  
Paolo Bifulco ◽  
Mario Cesarelli ◽  
Alistair McEwan ◽  
Hossein Moeinzadeh ◽  
...  
Keyword(s):  
Efficient Algorithm ◽  
Equilateral Triangle ◽  
Critical Analysis ◽  
Cardiac Cycle ◽  
Cardiac Activity ◽  
Central Point ◽  
Current Circulation ◽  
Central Terminal

Since its inception, electrocardiography has been based on the simplifying hypothesis that cardinal limb leads form an equilateral triangle of which, at the center/centroid, the electrical equivalent of the cardiac activity rotates during the cardiac cycle. Therefore, it is thought that the three limbs (right arm, left arm, and left leg) which enclose the heart into a circuit, where each branch directly implies current circulation through the heart, can be averaged together to form a stationary reference (central terminal) for precordials/chest-leads. Our hypothesis is that cardinal limbs do not form a triangle for the majority of the duration of the cardiac cycle. As a corollary, the central point may not lie in the plane identified by the limb leads. Using a simple and efficient algorithm, we demonstrate that the portion of the cardiac cycle where the three limb leads form a triangle is, on average less, than 50%.

Therapeutic Mechanisms of Suicidal Ideation

Crisis ◽  
2007 ◽  
Vol 28 (4) ◽  
pp. 198-203 ◽  
Author(s):  
Daniel Coleman ◽  
John T. Casey
Keyword(s):  
Suicidal Ideation ◽  
Strong Association ◽  
Automatic Thoughts ◽  
Cognitive Behavioral ◽  
Research Attention ◽  
Maladaptive Cognitions ◽  
Treatment Processes ◽  
Strong Correlate ◽  
Suicide Interventions ◽  
And Behavior

The treatment processes associated with reduced suicidal ideation have received little research attention. This study evaluates the influence on suicidal ideation of theory-based intrapsychic processes: maladaptive cognition and defensive style. Thirty-three community mental health patients completed questionnaires at two time points. Decreases in automatic thoughts were a strong correlate of decreased suicidal ideation, and decreases in immature defenses were a moderate strength correlate. These relationships remained significant even when controlling for initial level of depression. The theorized mechanisms of cognitive-behavioral and psychodynamic therapy had the expected effects on suicidal ideation. The strong association of decreased maladaptive cognitions with decreased suicidal ideation supports further development of cognitive-behavioral suicide interventions and clinical use of cognitive interventions. Psychodynamic processes in suicidal ideation and behavior warrant further exploration.

A New Sub-1 Volt 17ppm/°C Offset-Insensitive Resistorless Switched-Capacitor Bandgap Voltage Reference

2020 ◽  
pp. 2150029
Author(s):  
Emad Ebrahimi ◽  
Maliheh Arabnasery
Keyword(s):  
Process Variations ◽  
Voltage Divider ◽  
Cmos Technology ◽  
Reference Voltage ◽  
Cmos Process ◽  
Switched Capacitor ◽  
Voltage Reference ◽  
Op Amp ◽  
Offset Voltage ◽  
Bandgap Voltage Reference

A new PVT compensated voltage reference is presented by using switched-capacitor (S.C.) technique. In the proposed bandgap voltage reference (BGR), a p–n junction is biased with different currents during two different phases and required PTAT and CTAT voltages generated and held by two capacitors. Using a capacitive voltage divider, the PTAT voltage is weighted such that the sub-1V bandgap voltage is achievable. In order to cancel the effect of op-amp offset and to relax the design of op-amp, the offset voltage of the op-amp is sampled by a capacitor during a specified phase and inversely is added to the final bandgap voltage in next phase. The analysis of the proposed S.C. BGR is supplemented by simulation of a 0.5-V BGR with 28[Formula: see text][Formula: see text][Formula: see text]W power consumption in a standard 0.18[Formula: see text][Formula: see text][Formula: see text]m CMOS technology. Simulation results show that the average temperature coefficient of the S.C. BGR is 17[Formula: see text]ppm/∘C and it is robust against the process variations. Applying an arbitrary 100-mV op-amp offset results in a lower than 1.1[Formula: see text]mV deviation in generated reference voltage. Due to the better matching of MIM capacitors in CMOS process (rather than resistors used in conventional BGR) the proposed S.C. bandgap provides good accuracy without any post trimming. Monte–Carlo analysis shows that [Formula: see text]/[Formula: see text] of the generated reference voltage is as low as 0.7%. The sensitivity of the proposed BGR to supply variation is also less than 1%/V.

3.48-nW 58.4ppm/∘C Sub-threshold CVR with Four Transistors and Two Resistors

2021 ◽  
Author(s):  
Mohammadreza Rasekhi ◽  
Emad Ebrahimi ◽  
Hamed Aminzadeh
Keyword(s):  
Process Variations ◽  
Mean Value ◽  
Absolute Temperature ◽  
Reference Voltage ◽  
Cmos Process ◽  
Voltage Reference ◽  
Ultra Low Power ◽  
Low Power Cmos ◽  
Simulation Results ◽  
Cmos Voltage Reference

In this paper, an ultra-low power CMOS voltage reference capable of operating at sub-1[Formula: see text]V input supply is proposed. Four transistors biased in weak inversion are used to generate the required complementary-to-absolute-temperature (CTAT) and proportional-to-absolute-temperature (PTAT) voltages of the proposed circuit. Self-biasing of nature of the proposed configuration in the form of operational amplifier (opamp)-free ensure nano-power operation and eliminate the need for lateral bipolar junction transistors (BJTs) and offset cancelation techniques. A prototype of the circuit is designed and simulated in a standard 0.18-[Formula: see text]m CMOS process. Post-layout simulation results show that the circuit generates a reference voltage of 494[Formula: see text]mV with temperature coefficient (TC) of 58.4[Formula: see text]ppm/∘C across [Formula: see text]C to 85∘C; while the consuming power is lowered to 3.48[Formula: see text]nW at the minimum supply of 0.8[Formula: see text]V. The line sensitivity is 0.7%/V for the supply voltages from 0.8[Formula: see text]V to 1.8[Formula: see text]V, whereas the power supply ripple rejection (PSRR) is [Formula: see text]49.06[Formula: see text]dB at 1[Formula: see text]Hz. Monte Carlo simulation results of the voltage reference show a mean value of 497.2[Formula: see text]mV with [Formula: see text]/[Formula: see text] of 1.7%, demonstrating the robustness of the generated reference voltage against the process variations and mismatch.

Demonstration of High Temperature Bandgap Voltage Reference Feasibility on SiC Material

2010 ◽  
Vol 645-648 ◽  
pp. 1131-1134 ◽  
Author(s):  
Viorel Banu ◽  
Pierre Brosselard ◽  
Xavier Jordá ◽  
Phillippe Godignon ◽  
José Millan
Keyword(s):  
High Temperature ◽  
Barrier Height ◽  
Ideality Factor ◽  
Schottky Diodes ◽  
Experimental Results ◽  
Voltage Reference ◽  
Bandgap Voltage Reference ◽  
Stable Voltage

This work demonstrates that a stable voltage reference with temperature, in the 25°C-300°C range is possible with SiC. This paper reports the simulated and experimental results as well and a practical and simplified vision on the principles of thermally compensated voltage reference circuits, usually named bandgap references. For our demonstration, we have used SiC Schottky diodes. The influence of the barrier height and the ideality factor on the voltage reference and a comparison between simulated and experimental results are also presented.

Study on the Feasibility of SiC Bandgap Voltage Reference for High Temperature Applications

2011 ◽  
Vol 679-680 ◽  
pp. 754-757 ◽  
Author(s):  
Viorel Banu ◽  
Phillippe Godignon ◽  
Xavier Jordá ◽  
Mihaela Alexandru ◽  
José Millan
Keyword(s):  
High Temperature ◽  
Output Voltage ◽  
Schottky Diodes ◽  
Experimental Results ◽  
Bandgap Reference ◽  
Voltage Reference ◽  
Bandgap Voltage Reference ◽  
Bipolar Diodes ◽  
Stable Voltage ◽  
Temperature Applications

This work demonstrates that a stable voltage reference with temperature, in the 25°C-300°C range is possible using SiC bipolar diodes. In a previous work, we have been demonstrated both theoretical and experimentally, the feasibility of SiC bandgap voltage reference using SiC Schottky diodes [1]. The present work completes the investigation on SiC bandgap reference by the using of SiC bipolar diodes. Simulated and experimental results for two different SiC devices: Schottky and bipolar diodes showed that the principles that govern the bandgap voltage references for Si are also valid for the SiC. A comparison between the output voltage levels of the two types of bandgap reference is also presented.

scholarly journals WCTECGdb: A 12-Lead Electrocardiography Dataset Recorded Simultaneously with Raw Exploring Electrodes’ Potential Directly Referred to the Right Leg

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3275
Author(s):  
Hossein Moeinzadeh ◽  
Joseph Assad ◽  
Paolo Bifulco ◽  
Mario Cesarelli ◽  
Aiden O’Loughlin ◽  
...  
Keyword(s):  
Large Amplitude ◽  
Cardiac Cycle ◽  
P Wave ◽  
T Wave ◽  
Conductive Pathway ◽  
Initial Assumption ◽  
Case Assessment ◽  
The Right ◽  
Central Terminal

With this paper we communicated the existence of a surface electrocardiography (ECG) recordings dataset, named WCTECGdb, that aside from the standard 12-lead signals includes the raw electrode biopotential for each of the nine exploring electrodes refereed directly to the right leg. This dataset, comprises of 540 ten second segments recorded from 92 patients at Campbelltown Hospital, NSW Australia, and is now available for download from the Physionet platform. The data included in the dataset confirm that the Wilson’s Central Terminal (WCT) has a relatively large amplitude (up to 247% of lead II) with standard ECG characteristics such as a p-wave and a t-wave, and is highly variable during the cardiac cycle. As further examples of application for our data, we assess: (1) the presence of a conductive pathway between the legs and the heart concluding that in some cases is electrically significant and (2) the initial assumption about the limbs potential stating the dominance of the left arm concluding that this is not always the case and that might requires case to case assessment.

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