Electrical and Computer Engineering Commons^™

Crosstalk In Passive Matrix Polymer Led Displays, David Braun

Electrical Engineering

Passive matrix displays based on polymer and organic light-emitting diodes (LEDs) suffer from crosstalk, the emission of light from pixels other than those selected. This article explores the topic of crosstalk both with an approximate but analytic model and by means of more exact circuit simulation in order to explain the causes of crosstalk and to quantify the consequences. We conclude that crosstalk has implications for display power consumption.

Electroluminescent Device Comprising A Transparent Structured Electrode Layer Made From A Conductive Polymer, Aemilianus G. J. Staring, David Braun

Electrical Engineering

An electroluminescent (EL) device is (1) composed of polymeric LEDs comprising an active layer (7) of a conjugated polymer and a transparent polymeric electrode layer (5) having electroconductive areas (51) as electrodes. Like the active layer (7), the electrode layer (5) can be manufactured in a simple manner by spin coating. The electrode layer (5) is structured into conductive electrodes (51) by exposure to UV light. The electrodes (9) and (51) jointly form a matrix of LEDs for a display. When a flexible substrate (3) is used, a very bendable EL device is obtained.

My Methanol Motorcycle, Art Maccarley

Electrical Engineering

.

Markovian Decision Control For Traffic Signal Systems, Xiao-Hua Yu, Allen R. Stubberud

Electrical Engineering

Setting signals at intersections to minimize the queue length and vehicle delay time is a key goal in traffic management. In this paper, a new control strategy for a signalized traffic intersection is developed by applying Markovian decision control theory. Statistical analysis of simulation results with different arrival rates indicate the excellent potential of this approach.

A New Control Strategy For A Signalized Traffic Intersection, Allen R. Stubberud, Xiao-Hua Yu

Electrical Engineering

A traffic control problem can be formulated as a decision-making problem for a stochastic dynamic system. Optimal traffic signal settings at intersections can minimize the vehicle delay time or the queue length at a stop line. In this paper, a new adaptive control strategy for signalized intersections is developed and tested by simulation. The simulation results show significant improvement over the traditional fully actuated control algorithm, especially for the case of high volume traffic demand.

Motion-Compensating Long-Term Memory Prediction, Thomas Wiegand, Xiaozheng Zhang, Bernd Girod

Electrical Engineering

Motion-compensating long-term memory prediction extends the spatial displacement utilized in block-based hybrid video coding by a variable time delay permitting the use of more frames than the previously decoded one for motion compensation. The long-term memory covers the decoded frames of some seconds at encoder and decoder. We investigate the influence of memory size in our motion compensation scheme and analyze the trade-off between the bit-rates spent for motion compensated prediction and residual coding. Simulation results are obtained by integrating long-term memory prediction into an H.263 codec. PSNR improvements up to 2 dB for the Foreman sequence and 1.5 dB …

Block-Based Hybrid Video Coding Using Motion-Compensated Long-Term Memory Prediction, Thomas Wiegand, Xiaozheng Zhang, Bernd Girod

Electrical Engineering

Our new approach extends the spatial displacement vector utilized in block-based hybrid video coding by a variable time delay permitting the use of more frames than the previously decoded one for motion compensation. The longterm memory covers the decoded frames of some seconds at the encoder's as well as the decoder's side. This scheme is well suited in cases of repetition in the sequence, e.g. a head is rotating back into its old position, or if the camera is shaking. However, transmission of the variable time delay requires additional bit-rate which may be prohibitive when the size of the long-term …

Improved Biquad Structures Using Double-Output Transconductance Blocks For Tunable Continuous-Time Filters, Vladimir I. Prodanov, Micheal M. Green

Electrical Engineering

A family of g_m −C biquad structures is derived. These biquads require only a pair of grounded capacitors and three transconductors. It is shown that a pair of complex zeros can be realized simply by replicating the output stage of the transconductance block, thereby constructing a second output current that is proportional to the original output current. Although these biquad structures are very compact, they allow independent programming of the filter’s center frequency and Q. IC simulations and measurements are presented using a fifth-order tunable filter as an example.

Design Techniques And Paradigms Toward Design Of Low-Voltage Cmos Analog Circuits, Vladimir I. Prodanov, Michael M. Green

Electrical Engineering

Techniques for the design of robust low-voltage CMOS analog circuits are given. It is shown that both Vt-independence and proper alignment between the input and output swings are crucial for effective design of low-voltage circuits.

A Differential Active Load And Its Applications In Cmos Analog Circuit Designs, Vladimir I. Prodanov, Michael M. Green

Electrical Engineering

In this paper we describe a CMOS differential active load and show how it can be used to create various useful structures. Tunable current gain stages and current squaring circuits are discussed. Their connection to a differential pairbased transconductor results in broad-range tunable transconductor structures suitable for adaptive continuous-time filtering applications and a four-quadrant voltage multiplier.

Bipolar/Cmos (Weak Inversion) Rail-To-Rail Constant-G M Input Stage, Vladimir I. Prodanov, Michael M. Green

Electrical Engineering

A rail-to-rail constant-g_m input stage suitable for bipolar or weak inversion CMOS implementation is presented. To achwe rail-to rail operation, two complementary differential pairs driven in parallel are used. To guarantee constant net transconductance each differential pair is augmented with a suitable biasing circuit. The biasing circuits are implemented without current mirrors, which results in low sensitivity to process variations and potentially higher bandwidth.

Characteristic Of A Broadband Ti:Linbo3, Optical Modulator With Buried Electrodes And Etched Grooves In The Buffer Layer, Jinyang Hu, Boyu Wu, Xiaomin Jin

Electrical Engineering

Traveling wave Ti:LiNbO₃ Mach-Zehnder optical modulators with buried electrodes and etched grooves in the SiO₂ buffer layer are analyzed by the finite element method. The tradeoff between the bandwidth BW and the half-wave voltage Vπ is discussed. The value of BW/V_π is used to weight the total performance of the modulator. Taking a thick buffer layer and etching deep grooves in the buffer layer are demonstrated as two effective methods to improve the performance of the modulator. A 3-dB optical bandwidth of 18 GHz with half-wave voltage 5V at a wavelength of 1.55 pm could be obtained …

Real-Time Range Image Segmentation Using Adaptive Kernels And Kalman Filtering, Fred W. Depiero, Mohan M. Trivedi

Electrical Engineering

Segmentation is a fundamental process affecting the overall quality and utility of a machine vision system. Range Profile Tracking (RPT) is a systematic approach for stable, accurate and high speed segmentation of range images that is based on Kalman filtering. Tests of RPT have produced stable decompositions of second order surfaces bounded by jump and crease discontinuities, having a volumetric error of a few percent, in under 6 sec. for a wide variety of conditions. Results from over 900 tests on synthetic scenes and 150 real range images are presented.

Simple Rail-To-Rail Constant-Transconductance Input Stage Operating In Strong Inversion, Vladimir I. Prodanov, Michael M. Green

Electrical Engineering

A CMOS op-amp input and gain stage suitable for low voltage operation are introduced. The input stage operates in strong inversion and has common-mode range beyond rail-to-rail. It uses two complementary differential pairs connected in parallel. The common-mode dependent current biasing employs only four transistors, does not require additional voltage references, current switches and/or current mirrors and does not increase the minimum required supply voltage. The variation of the net transconductance is approximately 15% over the entire common-mode range. The gain-stage has constant output resistance. In addition it reduces the variation of the net transconductance due to variations in μn/μp …

Graph Matching Using A Direct Classification Of Node Attendance, Fred Depiero, Mohan Trivedi, Steve Serbin

Electrical Engineering

An algorithm has been developed that finds isomorphisms between both graphs and subgraphs. The development is introduced in the object recognition problem domain. The method isolates matching subgraphs, finds a node-to-node mapping and reorders nodes, thus permitting a direct comparison to be made between the resultant graphs. The algorithm is of polynomial order. It yields approximate results, maintaining a performance level for subgraph isomorphisms at or above 95% under a wide variety of conditions and with varying levels of noise. The performance on the full size comparisons associated with graph isomorphisms has been found to be 100/100, also under a …

Cmos Current Mirrors With Reduced Input And Output Voltage Requirements, Vladimir I. Prodanov, Michael M. Green

Electrical Engineering

A CMOS current mirror with lower than V_DS(sat) input voltage requirement is presented. It is shown that the structure can be modified to provide cascode-type output resistance for output voltages even lower than 2 V_DS(sat). The topology of the proposed current mirror allows low distortion operation from a single 1.5V supply, which makes it attractive for low-voltage applications.

3-D Computer Vision Using Structured Light: Design, Calibration, And Implementation Issues, Fred W. Depiero, Mohan M. Trivedi

Electrical Engineering

Structured light (SL) sensing is a well-established method of range acquisition for computer vision. We provide thorough discussions of design issues, calibration methodologies, and implementation schemes for SL sensors. The challenges for SL sensor development are described and a range of approaches are surveyed. A novel SL sensor, PRIME, the PRofile Imaging ModulE recently has been developed and is used as a design example in the detailed discussions.

Biquad Gm-C Structures Which Use Double-Output Transconductors, Vladimir I. Prodanov, Michael M. Green

Electrical Engineering

Two Gm-C biquad structures are derived. They use only two grounded capacitors and three transconductors, two of which have double-outputs. The realization of the double-output transconductors is discussed. It is shown that only two additional transistors are needed to convert a single-output transconductor to a double-output one suitable for implementation of the proposed structures. HSPICE simulations and experimental results of a 5-th order inverse Gaussian filter using the proposed biquad structures are given.

Effects Of Hydrogen On Inp Light-Emitting Devices Etched In A Methane-Hydrogen Environment, Patricia Beck, Dennis J. Derickson, Forrest Kellert, Tim Bagwell

Electrical Engineering

Research has been conducted on the physical damage and hydrogenation effects during RF plasma exposure and epitaxial growth in the III-V material system. Device consequences of this damage or chemical alteration have received less attention, particularly in active light emitting devices. This paper discusses these effects for lasers and edge emitting light-emitting diodes (EELEDs) which use a ridge waveguide structure. By using analysis techniques such as SIMS we have concluded that methane-hydrogen reactive ion etching of InP induces hydrogen levels in an active device which are high enough to significantly alter the device properties. The decrease in light output is …

Visible Light Emitting Diodes Fabricated From Soluble Semiconducting Polymers, Alan J. Heeger, David Braun

Electrical Engineering

Visible light LEDs are produced having a layer of conjugated polymer which is cast directly from solution or formed as a gel-processed admixture with a carrier polymer. The LEDs can be formed so as to emit polarized light.

Electroluminescence And Photoluminescene Efficiency Of Poly(P-Phenylenevinylene) Deriatives, E. Staring, R. Demandt, David Braun, G. Rikken, Y. Kessener, A. Venhuizen, M. Van Knippenberg, M. Bouwmans

Electrical Engineering

Alkoxy, alkyl, and cyano derivatives of poly(p-phenylenevinylene) [PPV] are used as the emissive layers in light-emitting diodes [LEDs] to obtain luminescence from red to blue. We present the luminescence efficiency for these soluble PPV derivatives. comparing the photoluminescence [PL] yields with the electroluminescence [EL] yields. PL efficiency increases with the fraction of non-conjugated units. EL efficiency depends not only on the radiative recombination efficiency of the emitting material but also on carrier transport to and within the material. Efforts to improve the efficiency and long term stability of these polymer LEDs are challenged by efficient and balanced carrier …

Video Technologies For Roadway Surveillance And Automated Detection, C. Arthur Maccarley, Leonard Ponce

Electrical Engineering

Closed circuit television (CCTV) systems deployed on roadway networks are believed to be among the best mechanisms for providing useful, reliable information for effective traffic management. Video images may be displayed and viewed directly by traffic management personnel for surveillance purposes, or may be processed electronically for detection of traffic metrics such as average vehicle speed, flow volume, and traffic density.

This paper summarizes the current state-of-the art in video imaging and video signal processing technology for traffic surveillance and electronic detection. Technical considerations relevant to the selection of video cameras and computer vision hardware and software for this application …

Travelling Wave Electrode Optimization For High Speed Electro-Optic Modulators Using The Fourier Series Method, W. Boyu, X. Guangjun, Xiaomin Jin

Electrical Engineering

The performance of Z-cut Mach-Zehnder high speed LiNbO₃ amplitude modulators with a CPW traveling wave electrode, has been analyzed and optimally designed in detail by the Fourier series method. The effect of electrode and buffer layer thickness on the electric field distribution in the substract, effective micro- wave refractive index and characteristic impedance of CPW electrode, are discussed. Calculation shows that increasing the thickness of the electrode and SiO₂ buffer layer can improve the phase velocity mismatch between electric and optical waves, and the drive power required by the modulator with thin buffer layer and thick electrode is …

Schottky Effect At A Metal-Polymer Interface, G. Rikken, David Braun, E. Staring, R. Demandt

Electrical Engineering

We report the observation of the Schottky effect at the interface between a metal and a semiconducting polymer by means of internal photoemission spectroscopy. The bias dependence of the barrier provides information on the electrical properties of the polymer.

State-Of-The-Art: In Polymer Light-Emitting Diodes Neome Polymer Led Mini Symposium (15–17 September 1993, Eindhoven, The Netherlands), David Braun, Adam Brown, Emiel Staring, E. W. Meijer

Electrical Engineering

A symposium focused on recent progress in the field of polymer light-emitting diodes was held in Eindhoven during the period 15–17 September 1993. The following is a brief summary of highlights of the symposium. There will be no published proceedings.

A Current-Mode Fdnr Circuit Element Using Capacitive Gyrators, Vladimir I. Prodanov, Michael M. Green

Electrical Engineering

A current-mode implementation of a frequency-dependent negative resistance (FDNR) element is presented using a novel capacitive gyrator. This FDNR element lends itself well to the design of low-pass ladder filters and its use will result in a more efficient integrated circuit implementation than filters that simulate floating inductors using resistive gyrators.

Ultrafast Dynamics In Field-Enhanced Saturate Absorbers, J. R. Karin, R. J. Helkey, Dennis J. Derickson, R. Nagarajan, D. S. Allin, J. E. Bowers, R. L. Thornton

Electrical Engineering

Absorption recovery dynamics of GaAs/AlGaAs field-enhanced waveguide saturable absorbers are studied by pump-probe differential transmission measurements. We compare the response of bulk and single quantum well absorbers at different reverse bias levels and pump powers, and find an ultrafast transient in the response, followed by a slower rise before the final recovery. The absorption fully recovers after a few picoseconds, which is an important result for mode-locked lasers.

Journal Of Engineering Education Round Table: Reflections On The Grinter Report, James G. Harris, Eugene M. Deloatch, William R. Grogan, Irene C. Peden, John R. Whinnery

Electrical Engineering

The Round Table is a new presentation format for the Journal of Engineering Education. The purpose of the Round Table is to present the comments of several distinguished individuals about a topic as well as their responses to the comments offered by their colleagues. For the initial Journal of Engineering Education Round Table we asked for reflections about the Grinter Report, published in September 1955.

After a brief introduction to the topic of discussion, the invited participants present their views, and, then, respond to the remarks of their colleagues. The goal is two-fold: to present a spectrum of views on …

High Power Edge-Emitting Light Emitting Diodes At 1.5Μ With Extremely Low Back Facet Feedback, J. E. Fouquet, G. R. Trott, W. V. Sorin, M. J. Ludowise, D. M. Braun, Dennis J. Derickson

Electrical Engineering

This paper describes novel semiconductor sources for optical low coherence reflectometry (OLCR), a measurement technique for characterizing device and fiber reflections with high sensitivity and high spatial resolution. Lasers and conventional superluminescent LEDs are not suitable for OLCR because strong reflections from the back facets mask weak reflection signals from the device or fiber under test. Even standard edge emitting LEDs (EELEDs) show significant reflections, which have limited the dynamic range of previous measurements. Low source output powers have also limited sensitivity. In order to obtain high power while minimizing internal reflections, a high single pass gain device is required. …

Explanation Of Timing Jitter Mechanisms In Multisegment Mode-Locked Semiconductor Lasers, Dennis J. Derickson

Electrical Engineering

Multisegment mode-locked semiconductor lasers offer a simple, high performance solution for short pulse generation. Six mode-locking techniques used in multisegment mode-locked semiconductor lasers are shown. This paper concentrates on a theoretical explanation of the timing jitter mechanisms in these lasers with supporting experimental measurements. The analysis covers passive, hybrid, and active mode-locking techniques for both monolithic and external cavity devices. Timing jitter is a very important system consideration for most applications of mode-locked lasers.