ETD at Indian Institute of Science
Repository of Theses and Dissertations of Indian Institute of Science, Bangalore, India. The repository has been developed to capture, disseminate and preserve research theses of Indian Institute of Science.
Centre for Electronic Design and Technology (cedt)
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A New Digital Receiver For The Ooty Radio Telescope - Prabu, T
A new digital receiver was built for the Ooty Radio Telescope (ORT). This new digital receiver system functionally replaces many systems custom-built for various applications at ORT. The thesis presents the receiver design, tests conducted, contributions made, revisions to the receiver architecture and future scopes. The novelty of the receiver design is in treating the ORT as an array of 22 antenna elements. Simulation studies were carried out to analyze the array performance of ORT. The IF signals are digitized and processed by a combination of multiple FPGAs and computers. Major transport of data in the receiver is through high...
Compact Modeling Of Asymmetric/Independent Double Gate MOSFET - Srivatsava, J
For the past 40 years, relentless focus on Moore’s Law transistor scaling has provided ever-increasing transistor performance and density. In order to continue the technology scaling beyond 22nm node, it is clear that conventional bulk-MOSFET needs to be replaced by new device architectures, most promising being the Multiple-Gate MOSFETs (MuGFET). Intel in mid 2011 announced the use of bulk Tri-Gate FinFETs in 22nm high volume logic process for its next-gen IvyBridge Microprocessor. It is expected that soon other semiconductor companies will also adopt the MuGFET devices. As like bulk-MOSFET, an accurate and physical compact model is important for MuGFET based...
Integrated Magnetics Based DC-DC Converter Topologies For A DC Micro-Grid - Deepak, G
In the present day, owing to the increasing number of electronic loads such as computer power supplies, Compact fluorescent lamps (CFL) and the increasing number of sources such as solar photovoltaics, fuel cells (DC sources), DC Micro-grids provide a more efficient solution compared to the AC counterpart in terms of the number of stages involved in conversion. Also, the ability to be readily buffered to storage elements is an advantage in a DC system. Apart from this, there are no issues of frequency stability, reactive power transfer and ac power losses.
A DC micro-grid is effectively a multi-port dc-dc converter. The...
Grid Interactive Quality AC Power Supply With Switching Arm Based Integrated Magnetics For Dynamically Controlled Interconnection Among Multiple Sources And Loads - Roy, Sudhin
The extensive use of nonlinear loads in today’s world has inspired considerable research interest in the area of power quality improvement. This thesis proposes an integrated magnetics based compact solution which provides regulated, balanced and sinusoidal load voltage drawing sinusoidal and balanced currents from the grid. Thus, it supplies clean power to the load without polluting the grid. It consists of an EI shaped magnetic core and two compensators known as the series and shunt compensators. The series compensator ensures the quality of output voltage, where as the shunt one takes care of quality of the current drawn from the...
Bond Graph Model Of A Generalised Multiphase Electromagnetic Device With Magnetic Non-idealities - Rai, B Umesh
The electromagnetic machines like the dc, induction, synchronous motor/generator and the transformer have an energy flow framework that is similar. All these machines deal with electrical energy in the electrical domain that is interfaced with the magnetic domain. Except for the transformer, the other machines also have one more energy interface i.e. with the mechanical domain. In all these machines, the magnetic domain acts as the silent energy manager. The electrical and the mechanical domain energies will have to pass through the magnetic domain and appropriately get routed. In recognition of the commonality of this pattern of energy flow, this...
Some Applications Of Integer Sequences In Digital Signal Processing And Their Implications On Performance And Architecture - Arulalan, M R
Contemporary research in digital signal processing (DSP) is focused on issues of computational complexity, very high data rate and large quantum of data. Thus, the success in newer applications and areas hinge on handling these issues. Conventional ways to address these challenges are to develop newer structures like Multirate signal processing, Multiple Input Multiple Output(MIMO), bandpass sampling, compressed domain sensing etc. In the implementation domain, the approach is to look at floating point over fixed point representation and / or longer wordlength etc., related to number representations and computations. Of these, a simple approach is to look at number representation,...
Performance Modelling Of TCP-Controlled File Transfers In Wireless LANs, And Applications In AP-STA Association - Pradeepa, B K
Our work focuses on performance modelling of TCP-controlled file transfers in infrastructure mode IEEE 802.11 wireless networks, and application of the models in developing association schemes. A comprehensive set of analytical models is used to study the behaviour of TCP-controlled long and short file transfers in IEEE 802.11 WLANs. The results can provide insight into the performance of TCP-controlled traffic in 802.11 WLANs in a variety of different network environments. First, we consider several WLAN stations associated at rates r1, r2, ...,rk with an Access Point. Each station (STA) is downloading a long file from a local server, located on...
A Polymorphic Finite Field Multiplier - Das, Saptarsi
Cryptography algorithms like the Advanced Encryption Standard, Elliptic Curve Cryptography algorithms etc are designed using algebraic properties of finite fields. Thus performance of these algorithms depend on performance of the underneath field operations. Moreover, different algorithms use finite fields of widely varying order. In order to cater to these finite fields of different orders in an area efficient manner, it is necessary to design solutions in the form of hardware-consolidations, keeping the performance requirements in mind. Due to their small area occupancy and high utilization, such circuits are less likely to stay idle and therefore are less prone to loss...
Physics Based Analytical Thermal Conductivity Model For Metallic Single Walled Carbon Nanotube - Rex, A
Single-Walled Carbon Nanotube (SWCNT) based Very Large Scale Integrated circuit (VLSI) interconnect is one of the emerging technologies, and has the potential to overcome the thermal issues persisting even with the advanced copper based interconnect. This is because of it’s promising electrical and thermal transport properties. It can be stated that thermal energy transport in SWCNTs is highly anisotropic due to the quasi one dimensionality, and like in other allotropes of carbon, phonons are the dominant energy carriers of heat conduction. In case of conventional interconnect materials, copper and aluminium, although their thermal conductivity varies over orders of magnitude at...
Rectifier And Inverter System For Driving Axial Flux BLDC Motors In More Electric Aircraft Application - De, Sukumar
In the past two decades the core aircraft technology is going through a drastic change. The traditional technologies that is almost half a century old, is going through a complete revamp. In the new “More Electric Aircraft” technology many mechanical, pneumatic and hydraulic systems are being replaced by electrical and power electronic systems. Airbus-A380, Boeing B-787 are the pioneers in the family of these new breed of aircrafts. As the aircraft technology is moving towards “More Electric”, more and more electric motors and motor controllers are being used in new aircrafts. Number of electric motor drive systems has increased by...
Design & Implementation Of Low Power Sigma Delta ADCs For Wide Band Applications - Harish, C
This thesis focuses on the design and implementation of low power Σ∆ ADCs in 130 nanometer CMOS technology. The design issues in the implementation of a third order ADC with a multi-bit and single bit quantizer are discussed.
The advancement in CMOS technology has led to designing as much of electronics systems as possible with the digital circuits and digital signal processing replacing analog processing in most cases. Hence there is a need for digitizing analog signals with analog to digital converter (ADC). In communication systems this needs to be done immediately after the antenna in a receiver system. As...
Modeling, Optimization And Design Of A Solar Thermal Energy Transport System For Hybrid Cooking Application - Prasanna, U R
Cooking is an integral part of each and every human being as food is one of the basic necessities for living. Commonly used sources of energy for cooking are firewood, crop residue, cow dung, kerosene, electricity, liqueﬁed petroleum gas(LPG), biogas etc. Half of the world’s population is exposed to indoor air pollution, mainly the result of burning solid fuels for cooking and heating. Wood cut for cooking purpose contributes tothe16 million hectares(above4% of total area of India) of forest destroyed annually. The World Health Organization(WHO) reports that in 23 countries 10% of deaths are due to just two environmental risk...
Distributed Wireless Networks : Link Scheduling And Application Delay Modelling - Sunny, Albert
We address several problems that arise in a multihop wireless mesh network. First, we study the problem of joint congestion control, routing and MAC layer scheduling. We formulate the problem as an aggregate utility maximization problem and apply duality theory to decompose the problem into two sub-problems, namely, network layer congestion control and routing problem, and MAC layer scheduling problem. Given the link “prices", the source adjusts its rate based on the cost of the least-cost path to the destination, and sends traffic to the destination along the least-cost path, while link scheduling is carried out based on link prices....
Throughput Of Wireless Mesh Networks : An Experimental Study - Ramachandran, P
Mesh network is gaining importance as the next generation network for many high speed applications such as multimedia streaming. This is because it is easy and inexpensive to setup mesh networks with mobile and PDA devices and can be used as a private network. Hence research is active in the field of routing protocols and routing metrics to improve the mesh network performance. Though most of the protocols are evaluated based on simulation, we implemented protocols based on a few metrics like Expected Transmission Count (ETX) Per-hop Packet Pair Delay (Pkt Pair) and WCETT (Weighted Cumulative Expected Transmitted Time) to...
Multilevel Voltage Space Vector Generation For Induction Motor Drives Using Conventional Two-Level Inverters And H-Bridge Cells - Siva Kumar, K
Multilevel voltage source inverters have been receiving more and more attention from the industry and academia as a choice for high voltage and high power applications. The high voltage multilevel inverters can be constructed with existing low voltage semiconductor switches, which already have a mature technology for handling low voltages, thus improving the reliability of the overall inverter system. These multilevel inverters generate the output voltage in the form of multi-stepped waveform with smaller amplitude. This will result in less dv/dt at the motor inputs and electromagnetic interference (EMI) caused by switching is considerably less. Because of the multi-stepped waveform,...