Engineering Commons^™

Pixel Qualification Methods In Attributed Scattering Center Extraction, Justin Tyler Farmer

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Recent work with the spectrum-parted linked image test (SPLIT) uses polarization with Fourier-based peak detection to qualify pixels for attributed scattering center (ASC) extraction from synthetic aperture radar (SAR) phase history data. SPLIT is a two-stage, non-linear technique to extract ASCs. The first stage qualifies pixels for ASC attribution, but suffers from imaging sidelobe energy. Error in pixel qualification propagates to stage two: pixel attribution. In this work, a new ASC extraction method is proposed. It is based on 2-D Prony method and motivated by SPLIT. Position estimation performance of SPLITs local peak detection is compared to the 2-D Prony …

Hysteretic Controlled Dc-Dc Converters, Shweta Chauhan

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Switched-mode DC-DC converters are widely used in applications requiring step-up and step-down of DC voltages or currents. These converters find their use in portable applications such as laptops and smart phones, radio-frequency power amplifiers, as light emitting diode (LED) drivers, etc. The power converters consist of a switching network, energy storage elements such as inductors and capacitors, and a load resistor. Transformers are used in converters, which require isolation. The switching network comprises of MOSFETs and diodes. With improvement in the VLSI technology, smaller MOSFETs with increased power handling capability are pushing the speed of operation of these power converters …

Dynamic Repeater With Booster Enhancement For Fast Switching Speed And Propagation In Long Interconnect, Kaushik Reddy Katpally

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A System-on-a-Chip (SoC) has millions of transistors connected by wires or so called Interconnects. As CMOS technologies scale down, SoC becomes more complex and denser. The delays of basic cells decrease, hereby improving logic gate and logic block delay. However, long wires connecting logic blocks still contribute significant delays, which limit SoC's speed performance.

In this thesis, we take a practical approach towards reducing propagation delay in long wire (Interconnect). A dynamic repeater with Booster enhancement circuit is presented and analyzed in this regard. Both switching speed and Interconnect propagation delay are significantly improved upon locally enabling the Booster to …

16-Bit Digital Adder Design In 250nm And 64-Bit Digital Comparator Design In 90nm Cmos Technologies, Naga Venkata Vijaya Krishna Boppana

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High speed, low power, and area efficient adders and comparators continue to play a key role in hardware implementation of digital signal processing applications. Adders based on Complimentary Pass Transistor Logic (CPL) are power and area efficient, but are slower compared to Square Root Carry Select (SQRT-CS) based adders. This thesis demonstrates a unique custom designed 16-bit adder in 250-nm CMOS technology to obtain fast and power/area efficient features by combining CPL and CS logic. Comparing the results obtained for proposed 16-bit Linear CPL/CS adder with the BEC (Binary Excess-1 Code) based low power SQRT-CS adder, the delay is reduced …

6 Ghz Rf Cmos Active Inductor Band Pass Filter Design And Process Variation Detection, Shuo Li

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A 90nm CMOS active inductor band pass filter with automatic peak detection is demonstrated in this thesis. The active inductor band pass filter has a better performance than the passive band pass filter in on-chip circuit design, due to small area, larger gain and tunable frequency. However, process variation makes the active inductor band pass filter hard to be used widely in many applications. To settle this issue, an automatic voltage peak detector is introduced to detect the process variation direction and hope to be used to control the active inductor band pass filter center frequency and gain. The designed …

Multi-Finger Mosfet Low Noise Amplifier Performance Analysis, Xiaomeng Zhang

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Multi-finger layout technique has been extensively used in Nano-scale CMOS circuit design due to the increased circuit performance compared to a single finger layout. However choosing a finger width (W_f) and number of fingers (N_f) to optimize circuit performance is a challenging problem. In this thesis, the performances of 2.4GHz and 6.0GHz single ended low noise amplifiers (LNA) with fixed total transistor widths in 90nm CMOS technology are analyzed as function of number of fingers, bias voltage (V_bias) and channel length (L). The results show that the drain to source current, transconductance and effective gate capacitance increase with increasing number …

End-To-End Classification Process For The Exploitation Of Vibrometry Data, Ashley Nicole Smith

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Laser vibrometry provides a method to identify running vehicles' unique signatures using non-contact measurements. A vehicle's engine, size, materials, shape, and other attributes affect its vibration signature. To develop the capability to classify and identify these signatures, a robust aided target recognition (AiTR) end-to-end process is evaluated and expanded. The main challenge in classifying a vehicle's vibration signatures is presented by the operating conditions and parameters that vary as a function of sensor, environment, and collection locations on the target, among others. Some of the parameters affecting the vibration signatures include weather, terrain, sensor location, sensor type, and engine speed. …

Evaluation And Application Of Lte, Dvb, And Dab Signals Of Opportunity For Passive Bistatic Sar Imaging, Aaron S. Evers

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Due to the many advantages of passive radar and ubiquity of commercial broadcast transmitters, interest in passive bistatic radar (PBR) applications has continued to grow. More specifically, sources studying commercial orthogonal frequency division multiplexing (OFDM) waveforms for passive bistatic synthetic aperture radar (SAR) imaging have become more common. This work evaluates and applies long term evolution (LTE), digital video broadcast (DVB), and digital audio broadcast (DAB) signals of opportunity for passive bistatic SAR imaging.

First, implications of the structure and properties of each of the signal of opportunity's transmitted waveform are characterized by examining the waveform's self- and cross-ambiguity functions …

Null Convention Logic Asynchronous Register Full Path Completion Feedback Loop Using Two Stage Voltage Divider, Christopher P. Taylor

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As fabrication technologies improve logic densities increase. It becomes harder to mitigate clock skew and jitter. Higher clock rates combined with increased numbers of sinks increase mixed-system substrate noise. An increasingly popular approach to address these problems is clockless logic. One technique is Null Convention Logic (NCL). However, traditional NCL feedback loops have large area overhead and require many gate delays. This makes NCL impractical in many applications. In this paper we propose to replace the feedback logic with a two-stage voltage divider. Using our technique we show up to 50% area reduction and require only one unit gate delay.

Impact Of Sar Image Formation Quality On Target Separability, Cody A. Lawyer

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The polar format algorithm (PFA) allows the use of computationally efficient fast Fourier transforms in synthetic aperture radar (SAR) image formation, but introduces phase errors when making the far-field approximations that facilitate this approach. The phase errors cause spatially variant distortion and defocus in the formed image. These effects may complicate target recognition applications. To limit the impact of defocus, scene size is usually limited such that the maximum quadratic phase error within an image falls below some threshold. This thesis looks at how distortion and defocus affects the classification of targets, with the hope of developing an application-driven scene …

Two-Speed Control Of Compressors In Residentlial Air-Conditioning Systems, George Joseph Ramayya

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Residential air-conditioning systems pre-dominantly have single phase compressors and the new technology in use is Ultratech scroll compressors capable of running at partial and full capacity levels using electro-mechanical controls allowing for staged and more efficient operation based on system load conditions. This project is to look at electronic methods to obtain two-speed control to duplicate the Ultratech compressor and evaluate the performance of the control options. A triac control scheme is designed for worst case assuming maximum load conditions of compressor in an air-conditioning system. The control schemes are prototype tested on single phase motor and compressor motor for …

Biaxial Material Design Method For The Reduced Aperture Waveguide Model, Jason M. Brand

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The design and characterization of metamaterials has emerged as a field of great interest in electromagnetics in recent years. The characterization has been accomplished primarily by means of fabrication, measurement, and parameter estimation. Previous work by Knisely and Havrilla [8] has shown that biaxial anisotropy can be created by machining air vias uniaxially into a homogeneous, isotropic material. This research project proposes a design method for manufactured biaxial materials. Full wave modeling and simulation is used for samples with varying via size, separation and pose to obtain the scattering parameters S11 and S21. To compare the simulated S-parameters to theoretical …

Adaptive I/Q Mismatch Compensation For Wideband Receiver, Linda Zhu

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Wide working bandwidth is one of the main concerns in digital wideband receiver. The traditional digital receiver covers only one Nyquist zone, which bandwidth range is from DC to half of the sampling frequency. By utilizing in-phase/quadrature (I/Q) channels, wideband receiver is able to double the working bandwidth, which covers from DC to half of the sampling frequency and also from negative half of the sampling frequency to DC. However, I/Q mismatch in reality introduces unwanted signals, which significantly reduce the system performance and the quality of the received signals. In this thesis, an adaptive I/Q mismatch compensation technique is …

Non-Contact, Antenna-Free Probes For Characterization Of Thz Integrated-Devices And Components, Prasanna Kumar Daram

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The most common technology for electrical characterization of THz devices is DC-coupled contact probes. In this Masters thesis, a non-contact, antenna-free probe is analyzed for characterizing THz devices and integrated circuits. The probe consists of on-chip receiving or transmitting THz photomixers in a co-planar waveguide environment. Our probes are coupled to a CPW-embedded DUT by polarization current rather than conduction current and then down converted in frequency to baseband by an optically pumped photomixer. We investigated probe performance through numerical simulations using High Frequency Structure Simulator (HFSS) carried up to 1 THz and yielded a broadband design with DUT to …

Large-Signal Analysis Of Buck And Interleaved Buck Dc-Ac Converters, Sourav Dey

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With the improvement in the present day technology, power electronic engineers are more focused on systems which are fast and have better performance. Closed-loop systems with a fast response and better performance have been a priority these days. PWM converters are self-regulating voltage regulators with high efficiency. Depending upon the voltage level and the type of power conversion, different converters are used to meet the necessary demands. One such PWM converter is the, buck DC-AC converter which plays an important role in the applications related to high-frequency and low-power. Large-signal analysis of buck and buck-derived converters for both open-loop and …