Thesis

Thyristor frequency changer using discrete frequency modulation technique

Abstract : In recent years modulation techniques techniques have been introduced into power semiconductor switching devices have proved to be suitable elements for achieving the required modulation processes. Due to the development of these devices, modulation find widespread application in the power frequency conversion and power control. In the present work an attempt is made to use a frequency modulation of discrete form as a technique to development a frequency changer which may compete with the conventional power frequency changer.

إنجليزية

Design of rectangular microwave isolator

Abstract : One of the most useful microwave ferrite components is the isolator, which is a two-port device having unidirectional transmission characteristics. A common application uses an isolator between a high-power source and a load to prevent possible reflections from damaging the source. The most popular type of microwave isolator is the resonance isolator. A single tone resonance isolator with resonance frequency of 10 GHz, and a broad band resonance isolator have been designed and optimized.

إنجليزية

Compression of residual speech signals using wavelet transform

Abstract : Speech Communications were a major research area in signal processing domain since the first third of the last century. As digital telephony and digital communications are evolving and advancing in efficiency and services speech coding techniques were following it to match or to make use of the new features and conditions.

إنجليزية

Design and implementation of distributed control system for digital exchange

Abstract : The objective of this work is to design and implement the software and hardware of the distributed control system for digital exchange. The proposed distributed control system for digital exchange model consists of three layers which are master, slave and sub-slave layer. The practical model designed and implemented, consists of master and slave layer only. The Master-Layer of the practical model include personal computer (PC[A]) and Switching-Circuit (SC[A]). PC[A] is connected with the SC[A] through the parallel port.

إنجليزية

Design and simulation of digital down converter using FPGA

Abstract : The aim of this thesis is to design and implement Digital Down Converter (DDC) using Field Programmable Gate Array (FPGA) chip for input sampling frequency of 40 MHz and 25 KHz channel bandwidth. The Xilinx FPGA is chosen here with Virtex-II device to achieve this task for the DDC system implementation. The individual components of the DDC system are the mixer with its adder/subtractor and multiplier, Numerical Controlled Oscillator (NCO), and decimation filter. These components are software implemented using VHDL language, with the software called ModelSim version SE-EE 5.4a.

إنجليزية

Model emulation of mosfet devices using neural networks

Abstract : Emulating of electronic devices and circuits is an essential matter for the analysis and design of the analog/digital circuits. The accuracy of the emulating processes depends mainly on the accuracy of the models for the semiconductor devices forming the electronic circuits. One of these electronic devices is the MOSFET transistor that represents the most popular electronic device used in the analog and/ or digital circuits, and for this reason it has been chosen in this work.

إنجليزية

Application of the wavelet transform in denoising flow signals

Abstract : This research investigates the application of the discrete wavelet transform (DWT) to the problem of denoising flow signals. The flow signals were made available, for this work, from the records generated by single particle flowing in an experimental system, where each record has 256 data points sampled at a rate of 2000 sps. The measuring technique uses the space-periodic capacitance transducer (SPCT) which generates flow signals with a spectral content which depends on the velocity of the flowing particle above the transducer (SPCT).

إنجليزية

Design and simulation of a coherent GPS receiver

There are a growing number of applications worldwide that require regularly updated vehicle position and sometimes orientation. For example, applications based on in-car navigation systems require that the navigation computer knows the position of the car on the earth. In many cases, this requirement can be met by using the Global Positioning System (GPS). Although originally developed for the military, the GPS has proven to be an invaluable service for a multitude of civilian applications.

إنجليزية

Software simulation and implementation of speech security system over telephone network

Speech security is an important aim for users of many speech communication systems. Speech scramblers are gaining widespread acceptance as a means of enhancing protection in both military and civilian applications. Therefore, there is an increasing interest in speech scramblers due to the desire for secure speech communication over existing telephone channels with standard telephone bandwidth at acceptable speech quality and reasonable cost. In this thesis, different types of scrambling systems in different domains are presented.

إنجليزية

Design and implementation of software radio receiver over mobile Channel.

This thesis is concerned with the data transmission over a mobile radio channel, which is characterized a by multipath propagation with a Rayleigh fading at 900 MHz, for different Doppler frequencies. The work introduces software radio receiver design and simulation. It then attempts to develop the software radio receiver over a mobile radio channel. Many techniques were used to improve the performance of the data transmission like equalization and diversity. An adaptive equalizer is used in this work to reduce the effect of intersymbol interference (ISI).

إنجليزية