5 research outputs found
PROCESS AWARE ANALOG-CENTRIC SINGLE LEAD ECG ACQUISITION AND CLASSIFICATION CMOS FRONTEND
The primary objective of this research work is the development of a low power single-lead ECG
analog front-end (AFE) architecture which includes acquisition, digitization, process aware efficient
gain and frequency control mechanism and a low complexity classifier for the detecting asystole,
extreme bardycardia and tachycardia. Recent research on ECG recording systems focuses on the
design of a compact single-lead wearable/portable devices with ultra-low-power consumption and
in-built hardware for diagnosis and prognosis. Since, the amplitude of the ECG signal varies from
hundreds of µV to a few mV, and has a bandwidth of DC to 250 Hz, conventional front-ends use
an instrument amplifier followed by a programmable gain amplifier (PGA) to amplify the input
ECG signal appropriately. This work presents an mixed signal ECG fronted with an ultra-low
power two-stage capacitive-coupled signal conditioning circuit (or an AFE), providing programmable
amplification along with tunable 2nd order high pass and lowpass filter characteristics. In the
contemporary state-of-the-art ECG recording systems, the gain of the amplifier is controlled by
external digital control pins which are in turn dynamically controlled through a DSP. Therefore, an
efficient automatic gain control mechanism with minimal area overhead and consuming power in the
order of nano watts only. The AGC turns the subsequent ADC on only after output of the PGA (or
input of the ADC) reaches a level for which the ADC achieves maximum signal-to-noise-ratio (SNR),
hence saving considerable startup power and avoiding the use of DSP. Further, in any practical filter
design, the low pass cut-off frequency is prone to deviate from its nominal value across process
and temperature variations. Therefore, post-fabrication calibration is essential, before the signal
is fed to an ADC, to minimize this deviation, prevent signal degradation due to aliasing of higher
frequencies into the bandwidth
for classification of ECG signals, to switch to low resolution processing, hence saving power and
enhances battery lifetime. Another short-coming noticed in the literature published so far is that
the classification algorithm is implemented in digital domain, which turns out to be a power hungry
approach. Moreover, Although analog domain implementations of QRS complexes detection schemes
have been reported, they employ an external micro-controller to determine the threshold voltage. In
this regard, finally a power-efficient low complexity CMOS fully analog classifier architecture and a
heart rate estimator is added to the above scheme. It reduces the overall system power consumption
by reducing the computational burden on the DSP. The complete proposed scheme consists of (i)
an ultra-low power QRS complex detection circuit using an autonomous dynamic threshold voltage,
hence discarding the need of any external microcontroller/DSP and calibration (ii) a power efficient
analog classifier for the detection of three critical alarm types viz. asystole, extreme bradycardia
and tachycardia. Additionally, a heart rate estimator that provides the number of QRS complexes
within a period of one minute for cardiac rhythm (CR) and heart rate variability (HRV) analysis.
The complete proposed architecture is implemented in UMC 0.18 µm CMOS technology with 1.8 V
supply. The functionality of each of the individual blocks are successfully validated using postextraction
process corner simulations and through real ECG test signals taken from the PhysioNet
database. The capacitive feedback amplifier, Σ∆ ADC, AGC and the AFT are fabricated, and the
measurement results are discussed here. The analog classification scheme is successfully validated
using embed NXP LPC1768 board, discrete peak detector prototype and FPGA software interfac
Radio Communications
In the last decades the restless evolution of information and communication technologies (ICT) brought to a deep transformation of our habits. The growth of the Internet and the advances in hardware and software implementations modified our way to communicate and to share information. In this book, an overview of the major issues faced today by researchers in the field of radio communications is given through 35 high quality chapters written by specialists working in universities and research centers all over the world. Various aspects will be deeply discussed: channel modeling, beamforming, multiple antennas, cooperative networks, opportunistic scheduling, advanced admission control, handover management, systems performance assessment, routing issues in mobility conditions, localization, web security. Advanced techniques for the radio resource management will be discussed both in single and multiple radio technologies; either in infrastructure, mesh or ad hoc networks
Summary of Research 1994
The views expressed in this report are those of the authors and do not reflect the
official policy or position of the Department of Defense or the U.S. Government.This report contains 359 summaries of research projects which were carried out
under funding of the Naval Postgraduate School Research Program. A list of recent
publications is also included which consists of conference presentations and
publications, books, contributions to books, published journal papers, and
technical reports. The research was conducted in the areas of Aeronautics and
Astronautics, Computer Science, Electrical and Computer Engineering, Mathematics,
Mechanical Engineering, Meteorology, National Security Affairs, Oceanography,
Operations Research, Physics, and Systems Management. This also includes research
by the Command, Control and Communications (C3) Academic Group, Electronic Warfare
Academic Group, Space Systems Academic Group, and the Undersea Warfare Academic
Group
MS FT-2-2 7 Orthogonal polynomials and quadrature: Theory, computation, and applications
Quadrature rules find many applications in science and engineering. Their analysis is a classical area of applied mathematics and continues to attract considerable attention. This seminar brings together speakers with expertise in a large variety of quadrature rules. It is the aim of the seminar to provide an overview of recent developments in the analysis of quadrature rules. The computation of error estimates and novel applications also are described
Generalized averaged Gaussian quadrature and applications
A simple numerical method for constructing the optimal generalized averaged Gaussian quadrature formulas will be presented. These formulas exist in many cases in which real positive GaussKronrod formulas do not exist, and can be used as an adequate alternative in order to estimate the error of a Gaussian rule. We also investigate the conditions under which the optimal averaged Gaussian quadrature formulas and their truncated variants are internal