Electrical and Computer Engineering Commons^™

Complex Low-Pass Filters, Peter Kiss, Vladimir I. Prodanov, Jack Glas

Electrical Engineering

Quadrature zero-if transceivers suffer from the imbalance of the I and Q paths. By using a complex low-pass filter topology instead of a conventional pair of real low-pass filters, this imperfection can be reduced. Both analytical and numerical analysis show that the proposed technique is significantly more robust to circuit imperfections than the traditional architecture.

Automatic Speechreading With Application To Speaker Verification, Charles C. Broun, Xiaozheng Zhang, Russell M. Mersereau, Mark A. Clements

Electrical Engineering

Speech not only conveys the linguistic information, but also characterizes the talker's identify and therefore can be used in personal authentication. While most of the speech information is contained in the acoustic channel, the lip movement during speech production also provides useful information. In this paper we investigate the effectiveness of visual speech features in a speaker veri pound sterling cation task. We pound sterling rst present the visual front-end of the automatic speechreading system. We then develop a recognition engine to train and recognize sequences of visual parameters. The experimental results based on the XM2VTS database [1] demonstrate that …

Visual Speech Feature Extraction For Improved Speech Recognition, Xiaozheng Zhang, Russell M. Mersereau, Mark A. Clements, Charles C. Broun

Electrical Engineering

Mainstream automatic speech recognition has focused almost exclusively on the acoustic signal. The performance of these systems degrades considerably in the real world in the presence of noise. On the other hand, most human listeners, both hearing-impaired and normal hearing, make use of visual information to improve speech perception in acoustically hostile environments. Motivated by humans' ability to lipread, the visual component is considered to yield information that is not always present in the acoustic signal and enables improved accuracy over totally acoustic systems, especially in noisy environments. In this paper, we investigate the usefulness of visual information in speech …

Arrival Rate Identification For A Class Of Traffic Signal Control Problem, Xiao-Hua Yu, Allen R. Stubberud

Electrical Engineering

Setting signals at traffic intersections to reduce congestion is one of the most challenging problems in traffic management. To find the optimal control strategy, specific information of the traffic flows passing through intersections must be provided in advance. It has been shown that the Markovian decision control theory can be successfully applied to solve traffic signal control problems, when both the state transition probabilities and the one-step reward function are known. In this paper, an online parameter identification algorithm is investigated for adaptive Markovian decision control at an isolated traffic intersection with unknown vehicle arrival rates. The authors give a …

Thin Film Interference Filters For 25ghz Channel Spacing, M. A. Scobey, R. M. Fortenberry, L. F. Stokes, W. P. Kastanis, Dennis J. Derickson

Electrical Engineering

No abstract provided.

Wireless Lans, Jack Glas, Mihai Banu, Joachim Hammerschmidt, Vladimir I. Prodanov, Peter Kiss

Electrical Engineering

Wireless LANs based on the IEEE 802.11 standard have achieved wide customer acceptance in the enterprise environment. They are expected to continue to expand in popularity and become ubiquitous communication systems even in private and public places. This paper discusses the basics of the wireless LAN physical layer, focusing on radio transceiver specifications and design options.

Automatic Speechreading With Applications To Human-Computer Interfaces, Xiaozheng Zhang, Charles C. Broun, Russell M. Mersereau, Mark A. Clements

Electrical Engineering

There has been growing interest in introducing speech as a new modality into the human-computer interface (HCI). Motivated by the multimodal nature of speech, the visual component is considered to yield information that is not always present in the acoustic signal and enables improved system performance over acoustic-only methods, especially in noisy environments. In this paper, we investigate the usefulness of visual speech information in HCI related applications. We first introduce a new algorithm for automatically locating the mouth region by using color and motion information and segmenting the lip region by making use of both color and edge information …

Audio-Visual Speech Recognition By Speechreading, Xiaozheng Zhang, Russell M. Mersereau, Mark A. Clements

Electrical Engineering

Speechreading increases intelligibility in human speech perception. This suggests that conventional acoustic-based speech processing can benefit from the addition of visual information. This paper exploits speechreading for joint audio-visual speech recognition. We first present a color-based feature extraction algorithm that is able to extract salient visual speech features reliably from a frontal view of the talker in a video sequence. Then, a new fusion strategy using a coupled hidden Markov model (CHMM) is proposed to incorporate visual modality into the acoustic subsystem. By maintaining temporal coupling across the two modalities at the feature level and allowing asynchrony in the state …

Bimodal Fusion In Audio-Visual Speech Recognition, Xiaozheng Zhang, Russell M. Mersereau, Mark A. Clements

Electrical Engineering

Extending automatic speech recognition (ASR) to the visual modality has been shown to greatly increase recognition accuracy and improve system robustness over purely acoustic systems. especially in acoustically hostile environments. An important aspect of designing such systems is how to incorporate the visual component Into the acoustic speech recognizer to achieve optimal performance. In this paper, we investigate methods of Integrating the audio and visual modalities within HMM-based classification models. We examine existing integration schemes and propose the use of a coupled hidden Markov model (CHMM) to exploit audio-visual interaction. Our experimental results demonstrate that the CHMM consistently outperforms other …

Sampling Switch Having An Independent "On" Impedance, Adrian K. Ong, Vladimir I. Prodanov, Maurice J. Tarsia

Electrical Engineering

A sampling device for sampling an input signal in response to a pulse train of a sample signal. The sampling device includes a sampling transistor for creating samples in response to the sample signal. The sampling transistor has an impedance corresponding with the difference between the gate to source voltage and the threshold voltage of the sampling transistor. The sampling device also includes a control device for generating a control signal. The control device includes a bootstrap reference voltage source for providing a reference voltage in response to the sample signal, and a control circuit for generating the control circuit …

A Java-Applet-Based Three-Phase Power System Harmonics Simulator, Taufik, Linda Kakinami

Electrical Engineering

This paper presents the development of a Java applet to simulate three-phase power system when harmonics is being introduced. The applet-based makes the simulator a very useful visual tool in understanding how harmonics affects the shape of sinusoidal waveform and thus the quality of power resulted thereof. The use of Java applet also enables the simulator to be run through internet via web-browser, and hence improves its availability and accessibility. The skeleton of the simulator will first be described. Then, discussion on how to operate the simulator follows which includes an example with snapshots to demonstrate the execution of the …

Siptool: The 'Signal And Image Processing Tool' An Engaging Learning Environment, Fred W. Depiero

Electrical Engineering

The ‘Signal and Image Processing Tool’ is a multimedia software environment for demonstrating and developing Signal & Image Processing techniques. It has been used at Cal Poly for three years. A key feature is extensibility via C/C++ programming. The tool has a minimal learning curve, making it amenable for weekly student projects. The software distribution includes multimedia demonstrations ready for classroom or laboratory use. SIPTool programming assignments strengthen the skills needed for life-long learning by requiring students to translate mathematical expressions into a standard programming language, to create an integrated processing system (as opposed to simply using canned processing routines).

A Cmos Agc-Less If Strip For Bluetooth, Vladimir I. Prodanov, George Palaskas, Jack Glas, Vito Boccuzzi

Electrical Engineering

This paper presents an IF chain suitable for Low-IF fully-integrated GFSK receivers. The circuit performs amplification and channel selection (including image rejection). A five-pole Gm-C polyphase filter forms the core of the IF strip. The filter is current driven and has transimpedance gain of ≃ 120 kΩ. The filter is architectured so that GFSK signals with dynamic range exceeding 50dB can be decoded without the need of any automatic gain control. This AGC-less IF strip was fabricated in standard 0.25 µm CMOS process. It draws 6.2 mA from a 2.5 V supply and has better than 4.8 nA rms input …

Microwave Modulation Of A Quantum-Well Laser With And Without External Optical Injection, Xiaomin Jin, Shun-Lien Chuang

Electrical Engineering

We compare three microwave modulation methods experimentally and theoretically using a semiconductor quantum-well (QW) Fabry–Perot test laser: 1) direct microwave current modulation of the test laser (electrical modulation); 2) optical modulation by an external single-wavelength pump laser with a modulated optical injection power; and 3) electrical modulation of the test laser that is injection locked by an external single-wavelength pump laser with a constant injection power. This is the first direct comparison of the three modulation methods on the same QW laser, to the best of our knowledge. The bandwidth of optical absorption modulation is 7.7 GHz, which is 1.45 …

Greasing The Tenure Track 2, David Braun

Electrical Engineering

Some new faculty must balance the competing demands of the desire to teach effectively while maintaining a heavy teaching load. Oh, and, by the way, along the way to the tenure hurdle, research, professional development, and service duties may distract from family, friends, and real life. Based on the author’s participation in the NSF's New Century Scholars (NCS) Workshop at Stanford University as both a scholar (1999) and, subsequently, as a senior scholar (2000), this paper summarizes six useful tips for tenure-track faculty. This second paper in the series by NCS senior scholars provides the perspective of an engineering educator …

Using Lip Features For Multimodal Speaker Verification, Xiaozheng Zhang, Charles C. Broun

Electrical Engineering

With the prevalence of the information age, privacy and personalization are forefront in today's society. As such, biometrics is viewed as an essential component of current and evolving technological systems. Consumers demand unobtrusive and non-invasive approaches. In our previous work, we have demonstrated a speaker verification system that meets these criteria. However, there are additional constraints for fielded systems. The required recognition transactions are often performed in adverse environments and across diverse populations, necessitating robust solutions.

We propose a multimodal approach that builds on our current state-of-the-art speaker verification technology. In order to maintain the transparent nature of the speech …

7v Tristate-Capable Output Buffer Implemented In Standard 2.5v Cmos Process, Vladimir I. Prodanov, Vito Boccuzzi

Electrical Engineering

This paper describes high-voltage CMOS buffer architecture that uses low-voltage transistors. The voltage capability of the presented architecture is nearly three times larger than the voltage capability of the used MOSFET's. This buffer topology could be used to provide 3.3 V compatibility of 1.2 V and 1.5 V digital ICs implemented in standard CMOS technology. A 7 V circuit-prototype was fabricated in 0.25 /spl μ/m 2.5 V CMOS technology. Performed measurements demonstrate stress-free operationin both active and high-impedance mode.

Robust High-Pass And Notch Gm - (Grounded) C Biquads: How Many Different Topologies Are There?, Vladimir I. Prodanov

Electrical Engineering

This paper deals with Gm-C biquadratic filters that use grounded capacitors. We derive all practical HP and notch filter topologies that do not require critical component matching. The aim of this derivation was to discover new architectures. The result of this derivation is quite unexpected: there are only three distinct topologies (one notch and: two high-pass). None of them is particularly new because all reported in the literature biquad circuits are their embodiments.

Measurement Of Linewidth Enhancement Factor Of Semiconductor Lasers Using An Injection-Locking Technique, G. Liu, Xiaomin Jin, Shun-Lien Chuang

Electrical Engineering

A new method for measuring the linewidth enhancement factor of semiconductor lasers using the injection-locking technique is presented. This idea is based on the relation between the upper and lower bounds of the locked and unlocked regimes when the detuning of the pump and slave laser is plotted as a function of the injection power. Our results are confirmed with an independent measurement using amplified spontaneous emission (ASE) spectroscopy as well as our theory, which takes account of the realistic quantum-well (QW) band structure and many-body effects. This method provides a new approach to measure the linewidth enhancement factor above …

Feed-Forward Compensation Scheme For Feedback Circuits, Venugopal Gopinathan, Vladimir I. Prodanov

Electrical Engineering

A feed-forward compensated negative feedback circuit comprises an operational amplifier having an inverting and a non-inverting input and an output. A feedback element is connected between the output of the operational amplifier and its inverting input to form a negative feedback loop. The inverting input of the op-amp is driven with a first transconductance amplifier which produces an output current proportional to an input voltage. A feed-forward transconductance amplifier receives the input voltage and produces an inverted output current proportional to the input voltage. A feed-forward current is injected at the output of the operational amplifier. By providing at the …

Multimodal Fusion Of Polynomial Classifiers For Automatic Person Recognition, Charles C. Broun, Xiaozheng Zhang

Electrical Engineering

With the prevalence of the information age, privacy and personalization are forefront in today's society. As such, biometrics are viewed as essential components of current and evolving technological systems. Consumers demand unobtrusive and noninvasive approaches. In our previous work, we have demonstrated a speaker verification system that meets these criteria. However, there are additional constraints for fielded systems. The required recognition transactions are often performed in adverse environments and across diverse populations, necessitating robust solutions.

There are two significant problem areas in current generation speaker verification systems. The first is the difficulty in acquiring clean audio signals (in all environments) …

Multiple Differential Pair Transitor Architecture Having Transconductance Proportional To Bias Current For Any Transitor Technology, Vladimir I. Prodanov

Electrical Engineering

A multiple differential pair circuit is disclosed having a transconductance, g_m, proportional to the bias current, I₀, for any transistor technology. The transistors utilized to construct each of the differential transistor pairs in a multiple differential pair circuit operate in a non-exponential voltage-current (V-I) region. As multiple differential pair circuits are linearized, the effective transconductance, g_m, becomes (i) linearly dependent on bias current, and (ii) insensitive to the voltage-current (V-I) characteristics of the utilized devices. Methods and apparatus are disclosed that provide a linear transconductance, g_m, with respect to the bias current, …

Cultivating Graduate Students: Techniques To Inspire Effective Research, David Braun, Linda Vanasupa, Blair London, Kevin Kingsbury, Heather Smith

Electrical Engineering

Each year, U.S. institutions grant well over 10,000 bachelor's degrees in science and engineering. However, only a small fraction of those students pursue graduate study. Many who do often experience great difficulty partly due to a lack of preparation for research: the nature of research is inherently foreign to those who are accustomed to studying course material and demonstrating their mastery of it by passing an exam. Carefully involving undergraduates in research can be an effective means for inspiring students to pursue graduate study. We have found that one can create a positive research experience for the student by implementing …

Transient Response Of Passive Matrix Polymer Led Displays, David Braun, K. Erickson, G. Yu

Electrical Engineering

Video displays based on polymer and organic displays require high resolution and high data rates. However, the transient response of passive matrix displays based on polymer and organic light-emitting diodes limits display resolution, image uniformity, and image contrast. We use circuit simulation in order to quantify these consequences. This work analyzes how the transient response depends on display resolution, display geometry, pixel position, and row and column electrode design. We conclude that advanced display designs can achieve uniform images at high resolution and contrast.

Method To Optimize Polymer Film Spin Coating For Polymer Led Displays, M. Cecchi, H. Smith, David Braun

Electrical Engineering

Research and development of displays and image sensors based on semiconducting polymers require design of new polymer materials and evaluation of film properties. Application of statistical methods can expedite process development. Optimizing device performance entails determining the effect of several process parameters, necessitates numerous samples, and may consume more scarce new material than desired. Uniform film thickness, with no voids, pinholes, inhomogeneities, or particulate contamination across the substrate can improve display efficiency and uniformity. After performing and analyzing a two-cubed full-factorial experiment with three replicated center points, this paper concludes that spin velocity and polymer concentration have statistically significant effects …

On The Solution Of A Class Of Large Body Problems With Partial Circular Symmetry (Multiple Asymmetries) By Using A Hybrid-Dimensional Finite-Difference Time-Domain (Fdtd) Method, Dean Arakaki, Wenhua Yu, Raj Mittra

Electrical Engineering

This paper presents an efficient method to solve a large body scattering problem, viz. a paraboloid reflector antenna system, with only partial circular symmetry. The asymmetry in the system is introduced by two factors, viz. the microstrip feed and an inhomogeneous radome. The paper presents a novel approach, based on the equivalence and reciprocity principles and the “equivalent” aperture theory, to overcome the asymmetry problem. The technique thereby enables substantial computational efficiencies by analyzing the majority of the three-dimensional (3-D) computational domain in an effective two-dimensional (2-D) simulation, with the remainder being analyzed using a 3-D algorithm.

Theory And Experiment Of High-Speed Cross-Gain Modulation In Semiconductor Lasers, Xiaomin Jin, T. Keating, Shun-Lien Chuang

Electrical Engineering

We present theory and experiment for the high-speed modulation response of a quantum-well (QW) laser in the presence of an external microwave modulated optical pump in the gain region. The model includes the effects of pump-induced stimulated recombination and cross-gain saturation. Expressions for the small-signal modulation response of the test laser under gain modulation are derived. We also present experimental results using a multiple-QW InGaAlAs Fabry-Perot (FP) laser at 1.552 μm as the test laser and an external pump by a 1.542 μm DFB laser. Comparison between electrical modulation and optical cross-gain modulation (XGM) of the test laser is also …

A Technique For Analyzing Radiation From Conformal Antennas Mounted On Arbitrarily-Shaped Conducting Bodies, Dean Arakaki, Douglas H. Werner, Raj Mittra

Electrical Engineering

This paper presents an efficient method to solve the problem of radiation from conformal aperture and microstrip antennas mounted on arbitrarily-shaped conducting bodies. The method, based on the surface equivalence and reciprocity principles, uses a combination of the Finite Difference Time Domain (FDTD) and Method of Moments (MoM) techniques to substantially improve the computational efficiency of the radiation pattern calculation. When the geometry and location of the radiating element are modified, only a small portion of the overall analysis requires re-simulation. This leads to a significant improvement in computational efficiency over presently used techniques, and can substantially improve design efficiency …

Multi-Wavelength Polarization Scrambling Device, James R. Stimple, Dennis J. Derickson, Eugene Rudkevich

Electrical Engineering

A polarization scrambling device randomly varies the polarization states of multiple applied optical signals. The scrambling device includes a polarization scrambler coupled to a wavelength-dependent polarization randomizer having cascaded birefringent elements in which the axes of polarization of the cascaded elements are rotationally offset. The scrambling device causes random variations in the relative and the absolute polarization states of the applied optical signals. The birefringence, lengths, and number of cascaded birefringent elements are chosen to assure that the polarization states of optical signals at the different wavelengths are sufficiently randomized, even when the applied optical signals are closely spaced in …

A Multidisciplinary Polymer Electronics Laborary, David Braun, Kevin Kingsbury, Linda Vanasupa

Electrical Engineering

Semiconducting polymers blend several attractive features that enable inexpensive and unique applications. Forming the subjects of numerous research and development projects, semiconducting polymers also make excellent teaching tools. Since the materials and their applications benefit from intrinsically multidisciplinary approaches, polymer electronics exposes both students and faculty to fruitful interdisciplinary collaboration. This paper introduces semiconducting polymers, tours the Cal Poly polymer electronics lab facility, and summarizes lab projects and course modules completed to date.