Studying And Analyzing the modulators and demodulators of PCM

Modulating signals of transmission stations to reception stations is a key factor to guarantee the best possible transmission and reception of these signals .Digital modulation represents a huge evolution in communication field and modulation, which used to depend on analog signal modulation of one parameter-Amplitude . frequency or phase. Digital modulation depends on transforming the transmitted data signal (Bits) and then sending it as samples, and changed back into an analog signals in reception station . In digital systems, digital data are transformed into analog data in the transmitter and does the reverse in the receiver. In digital transmission, on the other hand, as in wired local area networks (WLAN), Digital data are transmitted in their digital state.

Study and analysis of error performance when using multiple pulse position modulation (PPM) over optical fiber

This paper is concerned with an original analysis of an multiple pulse position modulation (MPPM) scheme using graded-index plastic optical fiber.

Modulation schemes in LTE system downlink

Several new technologies had been presented in LTE system standards in order to achieve higher performance and more reliability than Previous cellular communications systems. The added new standards describe advanced technologies that integrated into the system environment so that we can meet subscribers Growing requirements. in this study we'll discuss in details the different patterns of modulation schemes, which are adopted in (3 GPP) standards for (LTE) system downlink.

Study and Evaluation of Mechanical Vibrations Using Computer

Machine developing aimsto improve its velocity, capability and production,this is accompanied by increase of Mechanical side effects and the dynamical loads between the Machines elements and parts, that may conduct to rise the Mechanical vibrations and may cause a lot of damage in these machines, and cause negative effects on the environmentaround these machines, the study of Mechanical vibrations has a significant importance for engineering and technical students, to have knowledge of Mechanical vibrations that may arise in the machines under design process, or to study the mechanical vibrations resulting in the machines under use to isolate these vibrations and attenuate of its negative effects, for that we introduced an simulation program to show and illustrate a method to simulate some mathematical models representing some of possible types of vibrations, and to determine the most important parameters that describe the different vibrations motions, we choose an suitable programing language to merge this simulated models with an illustration and learning texts and drawings and animations in one executable application, this application show the models and the results in simple and very clear manner, and show the results in high resolution comparing with other programing languages.

Evaluation Wireless Connection performance with respect to modulation scheme, transmitter power, effective interference and ECC threshold

Wireless communication has become more popular over the last decade. Although there are many advantages to use wireless over fixed line systems, there is a major disadvantage, which is a high transmission error rate in a temporal and permanent noisy environment. There are techniques to reduce effectiveness off transmission errors in wireless communications. We have discussed in this paper. Many methods and techniques have been implementing to deal and resist errors (by increasing transmission power, switching modulation scheme) as well as evaluation the wireless connection performance taking into account many factors.

Development electrical drive Vector control system for three phase induction motor Crane Wire, according to the principle indirect rotor field orientation

In this paper, the development of the drive system of the motor Wire port Crane according to the principle of the indirect field orientation. Require the operation of the port Crane operations, different operation situations of variable speed and Torque with time, which is a case dynamic electro and electro-magnetic transient, may affect the performance of operations, so therefore been building motor Wire port Crane operations system corps in winches achieve: - High performance and Efficiency. - Build the desired control system according to the principle of the Pulse Width Modulation (PWM) and the main power system, taking into account the reduction of changes DC-Link voltage and achieve maximum flux before starting the motor. - Reduction of excess Voltage that may appear on a DC-Link, using the brake Transistor with Brake resisters. At the end of the research has been reviewed and the search results that indicate the outstanding performance of the proposed system with the ability to use the same system to run automated processes different.

A Study of The Effectiveness and Sound Quality in Audio Compression Algorithms

The sound is an essential component of multimedia, and due to the needto be used in many life applications such as television broadcasting andcommunication programs, so it was necessary for the existence of audio signal processing techniquessuch as compressing, improving, and noisereduction. Data compression process aims to reduce the bit rate used, by doing encoding information using fewer bits than the original representation for transmitting and storing. By this process,the unnecessary information is determined and removed, that means it gives the compressed information for useable compression, which we need as a fundamental, not the minutest details. This research aims to study how to process sound and musical signal. It's a process that consists of a wide range of applications like coding and digital compression for the effective transport and storage on mobile phones and portable music players, modeling and reproduction of the sound of musical instruments and music halls and the harmonics of digital music, editing digital music, and classification of music content, and other things.

Effect of Adaptve Modulation on the data rate in current Mobile Networks

This works aims to study the performance of the mobile system via studying the effects of adaptive modulation technique on the data rate. Fuzzy logic technique is used as a tool to analyze the data rate of the downlink connection depending on type of modulation, coverage quality and the distant between the receiver and the transmitter. For parameters were considered as input parameters for the fuzzy logic system mainly are: power of the station, quality of coverage, the type of modulation technique and the signal to interface noise ratio. One parameter is used as an output of the fuzzy system which is spectrum efficiency in bit per second per hertz. Analytical study to select the optimal data rates for different modulation techniques will be considered. Additionally, studying the input and output memberships of the data rate parameters using fuzzy logic will be explained. Keywords: Data rate, downlink, signal to noise ratio, modulation type, Fuzzy logic, spectrum efficiency.

Analysis of Microwave Radio Link‘s parameters Using Fuzzy Logic Approach

This work aims to analyze the performance of the microwave radio link’s parameters used to connect different systems and intra systems. Fuzzy logic technique is used to study the difficulties of the radio link’s parameters based on type of modulation, and distance between the receiver and transmitter. Four parameters are used as an input parameters for the fuzzy logic system mainly: required power, the length of the microwave radio link, modulation type and the signal to noise ratio(S/N). The output parameter is determined to be the microwave link capacity. Analytical study to select the optimal microwave radio link parameters to examine the efficiency of the radio link capacity will be shown. Additionally, studying the input and output memberships of the microwave radio link parameters using fuzzy logic will be explained.

Improving Costas Radar Signal by Applying Variable Time Spacing Using Costas Array And Golomb Ruler

The normal Costas frequencies code sequence signal is very well known and important signal in pulse compression Radar. In this paper we present two algorithms to modify Costas sequence by arranging the frequencies of Costas signal in time, first using binary Costas array and second using Golomb Ruler. These methods enable us to control side-lobes and to improve Doppler frequency resolution of Ambiguity Function (AF). At first we present the principle of these methods Golomb Ruler and Costas array. Then we apply these two methods to normal Costas signal, modified Costas signal and step frequency modulation and calculate the AF for all. The results of comparison have shown that considerable reduction of side-lobes of AF is achieved by using these two methods, and consequently an improvement of AF is obtained.