Engineering Commons^™

Fpga Design Of A Hardware Efficient Pipelined Fft Processor, Ryan T. Bone

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Digital receivers involve fast Fourier transform (FFT) computations that require a large amount of arithmetic operations. The implementation of a FFT processor is one of the most challenging parts in the realization of a wideband receiver and its hardware complexity is very high. Hence, kernel function FFT processors have been proposed to meet real-time processing requirements and to reduce hardware complexity by rounding the kernel function to predetermined kernel points so as to eliminate the multipliers and use only shifters and adders or subtractors. Because of the nonlinear nature of this approximation by the rounding errors, spurious responses are generated …

Ici Reduction Methods For Mc-Cdma Systems, Meng Wu

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Multi-carrier code-division multiple-access (MC-CDMA) is an important multiple access candidate for 4G wireless communication system. While MC-CDMA provides high performance and high capacity in frequency selective fading channels, it is very sensitive to the signal distortion, especially the Inter Carrier Interference (ICI). We apply self-cancelation and a frequency transmission paradigm to MC-CDMA system to improve the sytem performance in an ICI rich environment. Furthermore, we combine the frequency transmission paradigm FD-MC-CDMA with ICI cancelation. Also, we apply all these three schemes into non-contiguous OFDM and non-contiguous MC-CDMA systems in simple Cognitive Radio communication environments and present the simulation results. Theoretical …

Influence Of Voltage Source Pulse Width Modulated Switching And Induction Motor Circuit On Harmonic Current Content, Martin T. Lange

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The purpose of this research is to present analysis of the harmonic content present in the phase current of a three phase induction motor while being powered by a voltage source pulse-width modulated (PWM) variable speed drive (VSD). First, the topology and circuit of the drive, its operational fundamentals and waveform appearance are presented and discussed. Next, the three-phase induction motor circuit model and operational characteristics are discussed. Finally, the harmonic content present in the induction motor phase current is determined by use of the PSPICE model. The ability of the PSICE simulation to determine harmonic content is established. It …

A Low-Cost Acoustic Array For Detecting And Tracking Multiple Acoustic Targets, Ellen E. Case

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A wide variety of real-world targets emit distinct acoustic signatures that not only distinguish them from one another but also provide spectral separation from background clutter. While acoustic signatures are distinct, they can also be highly variable, even for an individual target, making detection and tracking a challenging problem. This thesis presents a low-cost acoustic array using commercial off-the shelf (COTS) hardware to detect and track multiple small, moving, acoustic targets. It implements a cross-correlation method for calibration, delay-and-sum beamforming, CA-CFAR detection, a discrete Kalman filter for tracking, and nearest neighbor data association. In addition, the array is designed to …

Automotive Battery State-Of-Health Monitoring Methods, Ryan J. Grube

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Effective vehicular power management requires accurate knowledge of battery state, including state-of-charge (SOC) and state-of-health (SOH). An essential functionality of automotive batteries is delivering high power in short periods to crank the engine. A well-known approach to battery SOH monitoring is to infer battery state-of-health from battery impedance or resistance, which is not robust to variation of battery types. The research and development of more reliable battery state-of-health monitoring methods to ensure vehicle start-up ability are presented in this thesis. The methods include a battery cranking voltage based method, a parity-relation based method using battery voltage and cranking current signals, …

An Algorithm For The Detection Of Handguns In Terahertz Images, Andrew J. Lingg

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This paper presents an algorithm for detecting handguns in terahertz images. Terahertz radiation is capable of penetrating certain materials which are opaque atoptical wavelengths, such as clothing, without the harmful effects of ionizing radiation. The approach taken is to segment objects of interest and classify them based on shape. We use a modified version of an active contour algorithm found in the open literature. Modifications include: a pre-processing step that includes clutter filtering and seeding of an initial contour; and a post-processing step that removes clutter pixels from the segmentation. The features used for classification are moment-based and Fourier shape …

Implementation Of Null Conventional Logic In Cots Fpga's, Mohamad Rajgara

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The digital world has been dominated by the growth of synchronous digital design techniques for last few decades. Traditional Boolean logic is symbolically incomplete since it has a separate control logic, time in the form of clock signal which be carefully integrated with the logic design, but with digital clock signal already in the GHz range, this integration is further complicated. One approach to address post GHz digital logic design is to use clockless or asynchronous digital design techniques. In the mid '90s Theaseus Logic Inc. proposed a method to design Asynchronous circuits using Null Convention Logic (NCL).This thesis introduces …

A Gnu Radio Based Software-Defined Radar, Lee K. Patton

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GNU Radio is an open source software-defined radio project, and the Universal Software Radio Peripheral (USRP) is hardware designed specifically for use with GNU Radio. Together, these two technologies have been used to implement very sophisticated, yet low cost, software-defined radios. Since software-defined radio and software-defined radar are really one in the same technologies, it stands to reason that GNU Radio and the USRP could be utilized to form a low cost radar sensor. In this thesis, we discuss the design of a prototype software-defined radar, built using the open source GNU Radio and open specification USRP projects. The prototype …

Change Detection Methods For Hyperspectral Imagery, Karmon Marie Vongsy

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This thesis studies the detection of changes using hyperspectral images. Change Detection (CD) is the process of identifying and examining temporal and spectral changes in signals. Detection and analysis of change provide valuable information of possible transformations in a scene. Hyperspectral imaging (HSI) sensors are capable of collecting data at hundreds of narrow spectral bands. Such sensors provide high-resolution spatial and spectrally rich information that can be exploited for CD. This work develops and implements various CD algorithms for detection of changes using Hyperspectral images. The main objectives are to study and develop different HSI change detection algorithms. The explored …

Development Of An Intelligent Autonomous Coffee Maker, Nicholas J. Vanderpool

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Using Intelligent Control Methodology Home coffee machines have improved over time with the addition of features such as self-activating timers and crude temperature controlled heating elements. However, home coffee brewer development has stagnated and has yet to achieve full automation status. Present coffee machines leave the user burdened with the mundane and messy task of preparing the coffee maker every time. Also, should the user decide to prepare less than an entire pot, he/she must estimate the correct amount of water and coffee to add. This can lead to a weak or strong brew, giving undesirable results. In order to …

High Spurious-Free Dynamic Range Digital Wideband Receiver For Multiple Signal Detection And Tracking, Vivek Sarathy

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The advent of field-programmable gate array (FPGA) has provided an excellent platform to market prototyping of full receiver-on-chip designs in a short time. The design of multi-tone wideband receiver has always been a challenge because of the difficulty to detect weak signals in the presence of noise in the frequency spectrum and also the presence of general spurs generated by the receiver. In this research, architecture for a FPGA-based 2.56-GSPS digital wideband receiver with multi-tone signal detection and tracking is designed to demonstrate the capability of replacing more expensive analog components into their cheaper digital design counterparts. Novel hardware implementations …

Multilingual Articulatory Features For Speech Recognition, Brian M. Ore

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Articulatory features describe the way in which the speech organs are used when producing speech sounds. Research has shown that incorporating this information into speech recognizers can lead to an improvement in system performance. The majority of previous work, however, has been limited to detecting articulatory features in a single language. In this thesis, Gaussian Mixture Models (GMMs) and Multi-Layer Perceptrons (MLPs) were used to detect articulatory features in English, German, Spanish, and Japanese. The outputs of the detectors were used to form the feature set for a Hidden Markov Model (HMM)-based phoneme recognizer. The best overall detection and recognition …

Parameterizable Channelized Wideband Digital Receiver For High Update Rate, Peter E. Buxa

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Wideband digital receivers are important components used prevalently by the United States Air Force for many modern electronic warfare systems. Currently, many digital receiver architectures are designed for a specific mission requirement and are not parameterizable, modular, or reusable for varying mission requirements. Also, many designs are technology, platform, and vendor dependent which make upgrading existing fielded systems costly and difficult. Additionally, current wideband FFT-based digital receivers must wait until a number of samples equal to the size of the FFT are collected before spectral information can be updated. Achieving a high spectral update rate is important for the accurate …

Design Of A Controller To Control Light Level In A Commercial Office, Saeid Javidbakht

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Proper amount of light in a business office is important for health and productivity of the employees. On a sunny day, there may be more than enough light entering the office from outside to carry out the necessary tasks. Presently, the main source of light in most offices is the fluorescent lamp. Thus, It is possible to save energy by dimming the fluorescent lamp. Dimming of the fluorescent lamp is possible by changing the frequency of the sinusoidal voltage or current. Hence, there is a need of a control system to adjust the light from the fixtures based on the …

Non-Cooperative Modulation Recognition Via Exploitation Of Cyclic Statistics, Eric C. Like

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This research proposes and evaluates a feature based modulation classification system designed to discriminate between AM, BFSK, OFDM, DS-CDMA, 4-ASK, 8-ASK, BPSK, QPSK, 8-PSK, 16- PSK, 16-QAM, and 64-QAM signals without a priori knowledge of critical signal parameters, including carrier frequency, symbol rate, or phase offset, among others. The classifier is based on the principles of cyclostationarity and leverages cyclic statistics to make its classification decision. The classification process is performed in a hierarchical process in order to exploit the lower variance of lower order cyclic statistics before making use of the higher order cyclic statistics. The initial classification is …

Algan/Gan Hemt Topology Investigation Using Measured Data And Device Modeling, Derrick Langley

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Investigation has been done on procedure, development, and verification of transistor topology for Aluminum-Gallium Nitride/Gallium Nitride (AlGaN/GaN) High-Electron Mobility Transistor (HEMTs). To date various models have been published that address modeling issues dealing with AlGaN/GaN HEMTs. Many models rely on analytic parameter solutions to help define model behavior. In order to find an optimum transistor at X-band frequency, 8-12 Gigahertz (GHz), layout, testing, modeling and simulation was conducted on various transistor topologies. Theoretical and experimental analysis has been completed for device operating point selection in measurement and modeling to account for self-heating and radio frequency (RF) dispersion effects. The model …

Investigation Of Cylindrically-Conformed Four-Arm Spiral Antennas, Douglas J. Glass

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A four-arm spiral antenna offers broadband frequency response, wide beamwidths, reduced size compared to other antenna designs, and the ability to determine the relative direction of an incident signal with appropriate mode-forming. The reduced overall area projection of the four-arm spiral antenna compared to other antenna designs and the ability to be manufactured in a planar format allows the antenna to reside within an Unmanned Air Vehicle (UAV) fuselage. This thesis investigates the effects of cylindrically-conforming two different designs of a four-arm spiral antenna to reside within the fuselage of a medium-sized UAV. Theoretical predictions of antenna performance were created …

Improved Thresholding Technique For The Monobit Receiver, Jonathan Gordon Buck

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Wideband digital receivers typically use a very high sampling rate to capture a signal for near real-time processing. Very robust digital techniques, like the Monobit FFT technique, have been developed to provide near real-time processing of captured timedomain signals. Most of these techniques trade accuracy for processing speed by approximating computationally complex mathematical operations. The approximation sometimes makes it difficult to detect multiple signals if the difference between their amplitudes is more than a few dB. This thesis presents a dynamic thresholding technique for multi-tone signal detection. The technique is based on setting an allowable ratio between the magnitude of …

Analysis Of A Small-Signal Model Of A Pwm Dc-Dc Buck-Boost Converter In Ccm, Julie Joann Lee

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The objective of this research is to analyze and simulate the pulse-width-modulated (PWM) dc-dc buck-boost converter and design a controller to gain stability for the buck-boost converter. The PWM dc-dc buck-boost converter reduces and/or increases dc voltage from one level to a another level in devices that need to, at different times or states, increase or decrease the output voltage.

In this thesis, equations for transfer funtions for a PWM dc-dc open-loop buck-boost converter operating in continuous-conduction-mode (CCM) are derived. For the pre-chosen design, the open-loop characterics and the step responses are studied. The converter is simulated in PSpice to …

Fpga Based Hardware Implementation Of Advanced Encryption Standard, Sowrirajan Sampath

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On October, 2, 2000, The National Institute of Standards and Technology (NIST) announced Rijndael as the new Advanced Encryption Standard (AES). The other competing algorithms were Mars, RC6, Serpent and Two-fish. The Predecessor to the AES was Data Encryption Standard (DES) which is considered to be insecure because of its vulnerability to brute force attacks. DES was a standard from 1977 and stayed until the mid 1990's. However, by the mid 1990s, it was clear that the DES's 56-bit key was no longer big enough to prevent attacks mounted on contemporary computers, which were thousands of times more powerful than …

Sic Schottky Diodes And Polyphase Buck Converters, Veda Prakash N. Galigekere

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The turn-on characteristics of a SiC Schottky diode are analyzed theoretically, by simulation, and by experiment. The static characteristics of SiC Schottky diodes and Si junction diodes are analyzed for normal and high temperatures. The effects of diffusion capacitance and junction capacitance on the turn-off transition of SiC Schottky diode have been analyzed theoretically. The turn-off transition of a SiC Schottky barrier diode is analyzed by modeling the metal-semiconductor junction capacitance considering the linear and the non-linear effects. Behavior of the linear and the non-linear metal-semiconductor junction capacitance models are evaluated exper- imentally. The performance of SiC Schottky diodes is …

On-Chip Signal Generation And Response Waveform Extraction For Analog Built-In-Self-Test, Brian Poling

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Built-In Self-Test (BIST) is a method of designing and creating an electronic chip or an electronic system that can self test for correct functionality and ensure no manufacturing defects. The reason for analog BIST is the testing of analog parts of analog and mixed-signal ICs is a costly process that traditionally requires the use of expensive high-end automatic test equipment. Due to the nature of the testing and length of the testing process, an efficient analog BIST scheme is in high demand for the ever increasing complexity of analog and mixed-signal circuits. This thesis presents a BIST scheme for generation …

Skin And Proximity Effects In Two Parallel Plates, Hamdi Eltayib Abdelbagi

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Time varying currents within winding and core conductors induce magnetic fields. When more than one conductor is present the resultant magnetic field can be found by adding the individual magnetic fields by superposition. The resultant magnetic field in turn induces eddy currents within each electrical component within the vicinity of the resultant magnetic field. Eddy currents flow in the opposite direction of the primary current and increase the resistance by reducing the area in which the primary current has to travel. Eddy currents also reduce the effectiveness of the conductors to conductor high frequency currents. Skin and proximity effects were …

Bezier Surface Generation Of The Patella, Dale A. Patrick

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A method to generate control points for a given collection of data points is developed. The shape characteristics of the patella are used as a case study. The developed computer graphic techniques are demonstrated using the given data of the 3-d patella model. Generation of curved surfaces in drafting has evolved over the years from draftsman who used tools such as French curves to today's drafting being well served by being able to apply numerical analysis on the ever increasing capabilities of computer. As an everyday observed example, nature very rarely produces two shapes that are equal to another. It …

Fpga-Based Implementation Of A Digital Processor For An Instantaneous Frequency Measurement Receiver, James M. Helton

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Digital wideband receivers are essential elements used in electronic warfare (EW) applications. Instantaneous Frequency Measurement (IFM) receivers are suitable for use in EW systems due to the ultrawide instantaneous radio-frequency (RF) bandwidth, fine-frequency resolution, and moderately high sensitivity and dynamic range. Conventional IFM receivers use analog components such as power dividers, crystal video detectors, and hybrids. This research presents the architecture and design implementation of a purely digital IFM receiver based on a patented algorithm courtesy of the United States Air Force. The invention is capable of detecting a short wave pulse with 1 MHz error for every 100 nsec. …

Stability And Static Noise Margin Analysis Of Static Random Access Memory, Rajasekhar Keerthi

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The transistor mismatch can be described as two closely placed identical transistors have important differences in their electrical parameters as threshold voltage, body factor and current factor and make integrated circuit design and fabrication less predictable and controllable. Stability of a static random access memory (SRAM) is defined through its ability to retain the data at low-VDD. It is seriously affected by increased variability of transistor mismatch and decreased supply voltage and therefore becomes a major limitation of overall performance of low-voltage SRAM in nanometer CMOS process. The stability limitation is addressed through the design of a seven-transistor (7T) SRAM …

Flexible Sigma Delta Time-Interleaved Bandpass Analog-To-Digital Converter, Ryan Edward Mcginnis

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Conversion of analog signals to their digital equivalent earlier in a circuit’s topology facilitates faster and more efficient exploitation of the information contained within. Analog-to-digital converters (ADCs) form the link between the analog and digital realms. In high frequency circuits ADCs must often be implemented further downstream after several stages of down-conversion, or through the use of more expensive technologies such as Bi-polar Junction Transistors or Gallium Arsenide. This thesis presents a technique to utilize Complimentary Metal Oxide Semiconductor technology in a parallel time-interleaved architecture. This will reduce circuit complexity and allow the ADC to be placed further upstream reducing …

Fpga Frequency Domain Based Gps Coarse Acquisition Processor Using Fft, Cyprian D. Sajabi

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The Global Positioning System or GPS is a satellite based technology that has gained widespread use worldwide in civilian and military applications. Direct Sequence Spread spectrum (DSSS) is the method whereby the data transmitted by the satellite and received by user is kept secure, low power and relatively noise-immune. The first step required in the GPS operation is to perform a lock on the incoming signal, both with respect to time synchronization and frequency resolution. Because of the need for reduced time to lock and also reduced hardware, algorithms based in the frequency domain have been developed. These algorithms take …

A Study Of The Impact Of Hardware Design Choices On The System Impulse Response Of A Signal-Level Radar Simulation, Kelly Renee Feirstine

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The main goal of this research is to study the effect of hardware design choices at the signal-level of an end-to-end radar system. An implementation of waveform diversity concepts, or the use of various waveforms in both transmit and receive is employed. An end-to-end Matlab simulation is developed such that the system impulse response to hardware imperfections and waveform parameters such as bandwidth and frequency channel spacing can be analyzed. Multiple frequency channels as well as multiple pulses are also considered in the research.

All hardware components are nonlinear to some degree. The nonlinearities of the hardware give rise to …

System Analysis And Rf-Floodlight Exploitation Of Short-Range Gotcha Repeaters, Jose A. Montes De Oca

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Emerging wide-area synthetic aperture radar (SAR) system concepts call for a single data collection platform to orbit a large ( e.g., 20-km) spot at a nominal range of 40-km. The large standoff distance and desire for fine resolution, coupled with a need for persistent real-time sensing, pose a significant challenge in terms of clutter-to-noise ratio (CNR) performance and data processing. Increased CNR and reduced processing load can be achieved by decreasing the range of the SAR system and the size of the area of interest. Employing multiple cooperating SAR systems allows the same overall coverage area to be maintained …