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- Creator:
- Ngai, Terence Nai-ching
- Description:
- Trellis-Coded Modulation (TCM) is a technique which combines channel coding and modulation for the transmission of digital signals over bandlimited channels. The basic idea is to use signal-set expansion to provide redundancy for coding, and to design coding and signal-mapping functions jointly so as to maximize directly the minimum Euclidean distance between coded signal sequences. The coding gain is achieved without sacrificing data rate or expanding bandwidth at the expense of increasing decoder complexity. Simple TCM schemes with 2 to 8 states can provide asymptotic coding gains of 3 dB compared to uncoded modulation. With more complex schemes, asymptotic coding gains of 6 dB can be realized. This paper describes the general principle and performance of conventional TCM schemes and the methods for maximizing such performance. Additional 1 to 2 dB gain can be obtained by introducing asymmetry to signal constellation or by transmitting multiple symbols per state transition. Performance improvement and drawbacks of these schemes are also discussed. The important effects of carrier-phase offset are presented. Problems arise when a carrier-modulated TCM signal is demodulated with a phase offset which could be caused by the inability of the phase-tracking scheme of the receiver to track phase disturbances instantly. Several concepts relating to the application of soft-decision maximum-likelihood Viterbi decoder are discussed. An example of soft-decision decoding of M-ary signals is also presented.
- Resource Type:
- Thesis
- Campus Tesim:
- Northridge
- Department:
- Engineering
- Creator:
- Favakehi, Mohamad
- Description:
- The objective of this project is to design and evaluate an interactive terminal using vacuum fluorescent technology. The display tube used is six lines by forty characters wide to enable to display 240 characters of display data. The touch input panel uses infrared switch matrix optical technology to transmit the operator's interaction to the host system. A detailed explanation of design philosophy will be presented and a comparison between various types of touch input technologies will be discussed.
- Resource Type:
- Thesis
- Campus Tesim:
- Northridge
- Department:
- Engineering
- Creator:
- Talebian, Sasan
- Description:
- The objective of this project is to discuss the assembly, behavior, building code requirements, and standard design practices for horizontal and vertical wood diaphragms. The discussions presented are intended to highlight the basics involved in design of wood diaphragms as lateral resisting elements for structures. A brief overview of construction practices and requirements has been incorporated in the text to facilitate related design discussions. Key tables from Uniform Building Code, 1985 edition, are included in the appendix.
- Resource Type:
- Thesis
- Campus Tesim:
- Northridge
- Department:
- Engineering
- Creator:
- Coffey, Lavanson C.
- Description:
- This project focuses on the development and documentation of a case study based on the build-up, check-out, certification and testing of the Dynamic and Aerodynamic Load Test (DALT) facility. Located at the Pacific Missile Test Center (PMTC), Point Mugu, California, this one-of-a-kind test facility was constructed to support the dynamic testing of composite case rocket motors designed for long term air-launched missile applications. While this facility was originally considered to be only a small portion of the Composite Case Durability Investigation (CCDI) program, it turned out to be a major challenge that drove program schedules and costs. The CCDI effort began in April of 1984 and was scheduled for completion by September of 1987. The original cost for the Phase IV test effort was estimated at $580,000. At facility completion, in March of 1990, costs had exceeded $2 Million, and the test effort was just beginning. The scope of this final project includes a detailed look at the factors involved from planning through completion of the Phase IV full-scale test effort. The resultant identification of key factors that influenced the massive cost and schedule overruns leads to development of management strategies that may be applied in future Department of Defense multi-agency projects, thereby allowing improved performance.
- Resource Type:
- Thesis
- Campus Tesim:
- Northridge
- Department:
- Engineering
- Creator:
- Murga, Nelson
- Description:
- The purpose of this project is to describe the architecture of a parallel processing system that uses RISC type processors as its main CPUs. The system being described is a multiprocessor system in which the processors work together on a single task in order to resolve the task quicker. The desired system will show a linear relation between the number of processors used and the percentage of increase in performance. The paper first describes the various architectures that are used for multiprocessor systems. These are classified using Flynn's classification scheme. Three RISC processors are evaluated for their suitability for a multiprocessor system. The memory organization and I/0 organization is next described with an emphasis on a multiprocessor environment. Finally, a complete description of the multiprocessor system is given.
- Resource Type:
- Thesis
- Campus Tesim:
- Northridge
- Department:
- Engineering
- Creator:
- Wilson, Mark P.
- Description:
- An examination of 3 types of direct drive Permanent Magnet D.C. Linear Motors is presented. Both commutated Brushless and Brush type D. C. Linear Motors (DCLM) as well as non-commutated DCLM's (i.e. Voice Coil Actuators) will be evaluated in considerable detail. Basic theory, motor construction, principles of operation as well as performance calculations for each type will be presented. Applications, the different types of drive electronics, as well as the advantages and the disadvantages of each of three motors will be discussed. Three different methods for determining the flux density in the air gap of a DCLM will be presented. The values obtained by each of three methods; flux mapping the motors using Finite Element Analysis program, magnetic circuit analysis using equivalent circuit theory as well as the demagnetization curve method will be verified by experimental measurements of flux density on actual DCLMs.
- Resource Type:
- Thesis
- Campus Tesim:
- Northridge
- Department:
- Engineering
- Creator:
- Swamy, Bhaskar
- Description:
- The purpose of this project is to demonstrate the applications of discrete simulation to the manufacturing systems and provide an overview of different PC based manufacturing simulators. A case study is presented to show how simulation can be a successful project in improving productivity and reducing delivery time. There has been a dramatic increase in the use of simulation for manufacturing analysis during the past few years. This has been caused by greater complexity of an automated systems, and reduced computing costs brought about by improvements in simulation software. This has resulted in reduction of model development time, and availability of graphical animation. This in turn provides Engineering managers with greater understanding and use of simulation. Simulation provides users with a greater breadth and depth of information on which to base decisions. Although it is not an optimizing tool, it is capable of handling the complexity of large systems, even a whole factory. In addition, the simulation approach supports a sensitivity analysis by allowing rapid changes to the model and data. There are more than 25 simulation software packages available in the market today. As a result, a person trying to select simulation software for his/her organization or for particular application is now faced with a bewildering variety of choices in terms of technical capabilities, ease of use, and cost. The success of a simulation project depends as much on the proper management of the project as on the systems analysis techniques to improve productivity and performance.
- Resource Type:
- Thesis
- Campus Tesim:
- Northridge
- Department:
- Engineering
- Creator:
- Untiedt, Judy Lynne
- Description:
- This project addresses one aspect of the larger problem of automating a labor-intensive task currently performed by humans. The repetitive, time consuming task involves probing and testing hundreds of points and displaying the test locations on an oscilloscope during data acquisition. While there are a number of factors to be considered, determining the exact location and spatial orientation of the robot-prober relative to the DIB (Device Interface Board) is addressed here. The procedure must be noise tolerant and must occur in real-time. A survey of the affine transformation technique, that is, the orthographic parallel plane projection from a source plane onto a target plane, is presented as part of the analysis of the spatial transformation. Rather than analyzing all probe points, local image analysis is performed on a few objects to precisely determine the prober's position relative to the DIB. Procedures for feature extraction and geometric transformations are developed and implemented. Test results indicate that the procedures are capable of performing the required tasks.
- Resource Type:
- Thesis
- Campus Tesim:
- Northridge
- Department:
- Engineering
- Creator:
- Nelson, Eric A.
- Description:
- This report begins with the background of the problem and the need for implementing an integrated database for managing software testing. The technical section presents a proposed database design and methodology for solving the problems presented in the first section. Examples of reports that could be generated are presented in the results section. The conclusion section explores the strengths and weaknesses of proposed databases. The recommendations section makes recommendations for future databases and future reports. Examples of the input screens and the reports are presented in the appendices.
- Resource Type:
- Thesis
- Campus Tesim:
- Northridge
- Department:
- Engineering
- Creator:
- Smith, Rob, 1947-
- Description:
- This project investigates spread spectrum communications techniques with attention to mobile digital communication applications. A survey of the spread spectrum fundamentals concepts is made, followed by descriptions of a variety of applications. The common issue of receiver synchronization and various implementations are discussed. The generation of spreading codes is discussed at length. The mobile digital communication environment is described, with attention to spread spectrum performance. A comparison is made between spread spectrum communication systems and conventional communications, with spread spectrum offering significant advantages.
- Resource Type:
- Thesis
- Campus Tesim:
- Northridge
- Department:
- Engineering