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By Topic

Date 24-26 April 1998

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Displaying Results 1 - 25 of 109
  • Proceedings IEEE Southeastcon '98 'Engineering for a New Era'

    Publication Year: 1998
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    Freely Available from IEEE
  • Tutorial abstracts

    Publication Year: 1998 , Page(s): 413 - 414
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (159 KB)  

    First Page of the Article
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  • Index of authors

    Publication Year: 1998 , Page(s): 415 - 416
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    Freely Available from IEEE
  • A high DC-gain folded-cascode CMOS operational amplifier

    Publication Year: 1998 , Page(s): 176 - 177
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (120 KB)  

    The architecture of folded-cascode op-amp is commonly used in many analog applications. The cascode arrangement has high open-loop voltage gain in the low frequency range that make it easy to be designed as a high-speed operational amplifier. In this paper, we present the design of a fully differential folded-cascode operational amplifier that improves the limitation on the swing of the output signal of a common cascode architecture. The DC open-loop gain of the circuit is 4.7 K View full abstract»

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  • Distributed engineering courses with on-line components

    Publication Year: 1998 , Page(s): 212 - 215
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    In this paper, through two different teaching experiences, the role of the Internet in delivering effective educational opportunities is discussed. Due to the unprecedented technological advancements in recent years, the role of computer technology in offering distributed courses has changed forever. Two recent experiments were carried out by the College of Engineering at the University of Central Florida (UCF), USA. One engineering course was taught at UCF while one of the authors (course instructor) was on a Fulbright scholarship visit at the Princess Sumaya University College for Technology (PSUCT) in Jordan. The second engineering course was taught at PSUCT with the instructor at UCF View full abstract»

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  • A novel approach to adaptive nulling with neural networks

    Publication Year: 1998 , Page(s): 216 - 219
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB)  

    A neural network approach to the problem of finding the weights of one and two-dimensional adaptive arrays is presented. In modern cellular, satellite mobile communications systems, and in GPS systems, both the desired and interfering signals change their directions continuously. Therefore, a fast tracking system is needed to constantly track the users, and then adapt the radiation pattern of the antenna to direct multiple narrow beams to the desired users and nulls to the sources of interference. In the approach suggested in this paper, the computation of the optimum weights is viewed as a mapping problem which can be modeled using a suitable artificial neural network trained with input output pairs. Three-layer radial basis function neural networks (RBFNN) are used in the design of one and two-dimensional array antennas. The results obtained from this network are in excellent agreement with the Wiener solution. The networks implementing these functions are successful in tracking mobile users as they move across the antenna's field of view View full abstract»

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  • Multipath interference detector design for digital data transmission

    Publication Year: 1998 , Page(s): 376 - 379
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (192 KB)  

    In this paper, the effects of multipath transmission interference on a digital communication system is investigated. The channel model for multipath transmission consists of a direct transmission path from the transmitter to the receiver and subchannels corresponding to signals being reflected from the ground plane are included. The output of these subchannels are then recombined in a proper fashion to achieve a better performance. The received signal is modeled as the sum of signals (direct and reflected) having a fading amplitude, an incoherent phase, an attenuation, and a delay due to longer transmission paths. The number of subpaths are optimized to provide maximum improvement, i.e., the detector design is based on the Bayes criterion with a minimum probability of error for a given signal-to-noise ratio. Finally, the detector performance is evaluated in terms of the receiver operating characteristics curves for different signal-to-noise ratio levels View full abstract»

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  • Hardware design overview of a satellite scatterometer

    Publication Year: 1998 , Page(s): 244 - 247
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (280 KB)  

    This paper provides an overview of the hardware design of the scatterometer electronics subsystem (SES) which is the heart of the SeaWinds payload developed by the Jet Propulsion Laboratory (JPL) to fly on the Japanese ADEOS-II satellite. The SES provides the radar electronics function. There is also a scatterometer antenna subsystem (SAS) and a command and data subsystem (CDS) that comprises the entire SeaWinds payload. This hardware has been under development since early 1995 and has undergone a major design upgrade to provide a higher spatial resolution wind measurement. The hardware is currently at JPL undergoing system-level integration View full abstract»

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  • Simulation of a spaceborne radar altimeter

    Publication Year: 1998 , Page(s): 322 - 325
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB)  

    This paper describes a computer simulation developed for spaceborne radar altimeter applications. The simulation uses a behavioral model for an orbiting altimeter. The model developed is based on the GEOSAT Follow-On Radar Altimeter, but is general in nature and can be used as an analysis or design tool for altimeter design development, or testing View full abstract»

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  • Limitation of branch predictors: a case for multithreaded architectures

    Publication Year: 1998 , Page(s): 138 - 143
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (668 KB)  

    Conventional scalar architectures such as the superscalar or multiscalar architectures execute from a single stream, while a multithreaded architecture executes from multiple streams at a time. Several aggressive branch predictors have been proposed with high prediction accuracies but none of them can provide 100% accuracy. We show that multithreaded architecture is a better candidate for utilizing speculative execution than scalar architectures. Generally the branch prediction performance degradation is compounded for larger window sizes on scalar architectures, while for a multithreaded architecture, by increasing the number of executing threads, we could sustain a higher performance for a large aggregated speculative window size. Hence, heavier workloads may increase performance and utilization for multithreaded architectures. We present analytical and simulation results to support our argument View full abstract»

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  • Resource allocation for handoff in wireless ATM networks

    Publication Year: 1998 , Page(s): 240 - 243
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    Resource allocation for handoff in wireless ATM (WATM) networks has currently been an area of active research. This paper describes various issues and approaches related to resource management and efficient bandwidth allocation for handoff in a WATM network. Further, it reviews the existing approaches presented in the literature, looks at their advantages and drawbacks, and provides directions and suggestions for future research View full abstract»

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  • An 1-GHz CMOS voltage-controlled oscillator

    Publication Year: 1998 , Page(s): 174 - 175
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (112 KB)  

    In this paper we present the design of a CMOS voltage-controlled oscillator. The circuit is designed based on a 0.6 μm spdm CMOS technology. We use NMOS devices as variable capacitors for the implementation of negative impedance to achieve circuit oscillation. The control voltage of the circuit is ranged from 0 to 3 volts. The circuit oscillates at 1 GHz frequency View full abstract»

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  • The FDTD analysis of a microstrip patch antenna with dual feed lines

    Publication Year: 1998 , Page(s): 84 - 86
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (148 KB)  

    The finite difference time domain (FDTD) method is used for the analysis of a square microstrip patch antenna with two microstrip feed lines. Circular polarization is obtained by feeding the lines on adjacent sides of the antenna with Gaussian pulses that are 90° out of phase. The tuning characteristics of the antenna using two feed lines on opposite sides are presented View full abstract»

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  • Relative calibration of scatterometer antennas using land targets

    Publication Year: 1998 , Page(s): 334 - 337
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    In this paper a simple method for relative antenna calibration is applied to NSCAT (NASA Scatterometer), and the model used is described. Calibration data sets are extracted using high-resolution masks. Results are presented for the Amazon rain forest (traditionally used) and the Siberian plain. Beam correction tables are derived for balancing normalized radar backscatter coefficient measurements from different antennas View full abstract»

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  • A fast weighted median filter architecture for image processing

    Publication Year: 1998 , Page(s): 114 - 117
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    This paper presents an on-line weighted median filter architecture that is simple, fast, cost effective, and easy to implement. It has a great potential for being used in rank order filtering and image processing. The use of this architecture-which implements a high degree of parallelism-is not limited to weighted median filtering for it can be used in sorting any set of data on-the-fly, which makes it amenable to real-time image processing View full abstract»

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  • Spaceborne radar performance evaluation through computer simulation

    Publication Year: 1998 , Page(s): 330 - 333
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB)  

    Simulation plays an important role in the design and pre-launch evaluation of radar remote sensors. This involves both hardware and software emulation of the sensor operation in a space environment. This paper describes a space radar simulation developed as an engineering tool for radar sensor development at Raytheon E-Systems St. Petersburg View full abstract»

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  • An enhanced detection of the evoked potential signal using a hybrid QMF algorithm

    Publication Year: 1998 , Page(s): 24 - 27
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (252 KB)  

    The authors introduce an efficient technique to detect the evoked potential, EP, transients. A hybrid algorithm using Daubechies (1990, 1994) as the father and Coiflet as the mother wavelet is employed on both a single and four-averaged EP sweeps. A 60% reduction in the number of sweeps with a high quality performance has been achieved when compared to traditional techniques View full abstract»

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  • Efficient implementation of linear predictive coding algorithms

    Publication Year: 1998 , Page(s): 69 - 72
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (200 KB)  

    In linear predictive coding (LPC) analysis, the linear predictors are computed using the classical Levinson-Durbin algorithm. But the Levinson-Durbin algorithm is a processing bottleneck as it involves the addition of inner products in the calculation of the reflection coefficients. This paper develops and reports on modifications to the algorithm used in various speech processing and coding applications for efficient implementations View full abstract»

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  • Comparison of basic converter topologies for power factor correction

    Publication Year: 1998 , Page(s): 348 - 353
    Cited by:  Papers (49)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (352 KB)  

    Basic types of DC-DC converters, when operating in discontinuous conduction mode, have self power factor correction (PFC) property, that is, if these converters are connected to the rectified AC line, they have the capability to give higher power factor by the nature of their topologies. Input current feedback is unnecessary when these converters are employed to improve power factor. In this paper, basic types of DC-DC converter topologies are studied to investigate their self-PFC capabilities. Their input characteristics are compared and their input line current waveforms are predicted View full abstract»

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  • Comparison of on-resistance of a power MOSFET by varying temperature

    Publication Year: 1998 , Page(s): 264 - 267
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    The development of the power MOSFET allows an electronic circuit designer greater flexibility in high power switching applications. This experiment demonstrates that the on-resistance of a power MOSFET decreases significantly when the operating temperature decreases. A comparison of on-resistance is then generated at 77 K, 173 K, 243 K and 295 K to show the effect of cryogenic cooling View full abstract»

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  • An expert system for eigenfunction expansions of solutions to the wave, heat, and Laplace equations

    Publication Year: 1998 , Page(s): 283 - 286
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (148 KB)  

    We describe a new expert system, written in C, for expressing the eigenfunction expansions of solutions to the nonhomogeneous wave, heat and Laplace equations in rectangular, cylindrical, and spherical coordinates with Dirichlet, Neumann, or Robin boundary conditions, in either the time, Laplace or frequency domains. The output of the program is LATEX code expressing the expansion, with elaboration on the eigenvalues and the expressions for the coefficients therein View full abstract»

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  • Neural wavelet analysis of life threatening ventricular arrhythmias

    Publication Year: 1998 , Page(s): 228 - 229
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (120 KB)  

    One of the most important task which can be implemented by an automatic monitor of cardiac arrhythmias is the reliable detection of those arrhythmias which represent a serious threat to the patient. Among these, ventricular arrhythmias occupy a primary place, and in particular ventricular fibrillation (VF), ventricular tachycardia (VT) and atrial fibrillation (AF) because of the haemodynamic deterioration which they produce. Consequently, interest has arisen in the development of algorithms which could be transferred easily to a microprocessor system. We use the backpropagation training (BP) algorithm on wavelet transformed results to classify the three mentioned arrhythmias. The BP algorithm perform the gradient descent search to reduce the mean square error between the actual output of the network and the desired output through the adjustments of weights. The results show significant improvements in the sensitivity (95%) and specificity (92%) over previous studies View full abstract»

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  • An improved three coupled microstrip lines design curves

    Publication Year: 1998 , Page(s): 178 - 181
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (220 KB)  

    The analysis of three microstrip lines, using the method of lines is introduced. Design curves for three coupled microstrip lines with equal effective dielectric constant are obtained. Using these curves, the coupling region of some applications can be exactly calculated rather than using the approximation of taking the average of the wavelength of the three modes of propagation View full abstract»

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  • Analysis, design and simulation of a resonant DC link inverter for high power, high frequency brushless DC motor

    Publication Year: 1998 , Page(s): 109 - 113
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    The conventional voltage source inverter for motor drive encountered severe problems such as high EMI, wide range of harmonics, heavy acoustic noise and low efficiency. Resonant DC-link inverter technique becomes dominate in solving the above problems due to its simplicity in both power stage topology and control strategy. In this paper, operation principle of resonant DC-link inverter is analyzed. A design procedure of this type inverter for high power application (200 HP) is presented. PSPICE simulation on the designed resonant DC-link inverter has been conducted to verify its availability for high power application. The improvements in motor drive by using resonant DC-link inverter is shown by comparing the PSPICE simulation results of conventional hard switching inverter View full abstract»

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  • Ceramic block bandpass filter components for small quantity applications

    Publication Year: 1998 , Page(s): 144 - 147
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB)  

    A method is presented for the design of low cost, high dielectric ceramic, narrow bandpass filters at precise frequencies. Ceramic block filters are required to operate at tolerances far more stringent than cost effective low volume production build variations and manufacturing processes allow. As a result, this technology has only been applied to very high volume (ie, commercial) applications where the production costs can be sufficiently amortized. A multitude of military and industrial applications would be well served by the cost effective enabling of this technology for small quantity applications. Small size and weight combined with exceptional temperature and vibration stability in a low loss structure makes this a most desirable staple of RF signal processing View full abstract»

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