البحث — المستودع الرقمي العراقي

المستخلص: The traffic accidents became significantly obsession and concern for all members of society, and has become one of the most important problems that sap physical, human resources and human potential. The researches show that the damaged property and other costs may equal 3% of world’s gross domestic product, which have been required to work in finding solutions and suggestions and put them into practice to reduce these incidents.The insertion of preventive safety applications into the car system can avoid the above mistakes. In this work, a design and implementation of Frequency Modulation Continuous Wave (FMCW) radar system working at 77GHz for Adaptive Cruise Control (ACC) technology is proposed. Using MATLAB R 2013 which is a flexible system to estimate the speed and distance in accordance to vehicle ahead, which reduces the forces on the rate of accidents by warning the driver when two vehicle become too close.Also, the principle of FMCW radar is presented to generate Linear Frequency Modulated Continuous Wave (LFMCW) sweep waveform through frequency bands with triangular frequency modulation using Voltage Control Oscillator (VCO), a triangle sweep pattern adopt will resolve ambiguity without Doppler processing. which improves the decision making before hardware implementation.Proteus Professional v8 and Micro C PRO v 6.1 compiler is used for Peripheral Interface Controller (PIC) to design a proposed collision warning circuit with PIC16F887 and RS_232 serial port to send data using USART terminal for (short, middle, large) test range.A serial communication interface is used for sending the simulation results from MATLAB FMCW radar system to hardware easy PIC v7 board with PIC16F887 to forward collision warning circuit to alerts the driver of collision risk, Liquid Crystal Display (LCD) shows radar status (short, middle, large) in accordance to range between the vehicle that FMCW radar installed and the vehicle ahead.Graphic Liquid Crystal Display (GLCD) shows the car position and road lines. Piezo Buzzer will start singing to alerts the driver from danger road.The simulation design is achieving the desired performance, one parameter warrants further attention. In the FMCW configuration, the sweep time is about 25 microseconds. Therefore, the system needs to sweep a 140 MHz band within a very short period. Such an automotive radar may able to meet the cost requirement.

الصفحات الاولى:

مكان الجامعة: بغداد

اللغة: الانكليزية

الجامعة: الجامعة التكنولوجية - قسم الهندسة الكهربائية - فرع الهندسة الالكترونية

الدرجة: ماجستير

الموضوع الدقيق: هندسة الالكترونيك والاتصالات

السنة: 2014

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

اسم المشرف: منال حمادي جاسم

اسم المؤلف: تمارا زهير فاضل

تقييم اداء الكشف المباشر والمتشاكه في نظام اتصال الليفة الضوئية Performance Evaluation of Direct And Coherent Detections In Optical Fiber Communication System

المستخلص: تطورت خدمات الاتصالات بشكل متسارع في السنوات القليلة الماضية خصوصا في المسافات بعيدة المدى وبمعدل نقل البيانات بدقة عالية وخسائر قليلة في جميع انحاء العالم. وقدمت تقنيات مختلفة لزيادة سعة الارسال في انظمة اتصالات الالياف الضوئية بواسطة جمع مسارات البيانا | In recent years, there has been an extensive development of optical fiber services. They provide transmission over long distances at a high data rate with few losses all over the world. Different techniques have been introduced to increase the transmission capacity of optical fiber communication systems by a multiplexed high data rate stream into an optical fiber such as Dense Wavelength Division Multiplying (DWDM) technique. Since the deployment of DWDM technique, the focus on introducing large system capacity with high system performance, different detection techniques have been introduced to enhance the system performance with high sensitivity. In this work, two types of detection techniques (direct and coherent detection) have been evaluated and compared with each other. These detection techniques have been evaluated based on several models of encoding format such as Return to Zero - Differential Phase Shift Keying (RZ - DPSK) and Non Return to Zero - Differential Phase Shift Keying (NRZ - DPSK) at 10 Gb/s as a data rate.These systems were first simulated with a single channel to analyze the performance with no Stimulated Raman Scattering (SRS), Cross Phase Modulation (XPM) and Four Wave Mixing (FWM) effects. Whereby the system of 8×10 Gb/s is simulated at 200 GHz, 100 GHz and 50 GHz as channel spacing. Three types of dispersion compensation schemes are used in the link channel. These systems are simulated using (Optisystem version 10.0) software package. The performance of the designed systems are evaluated through Q.factor verses input power and Bit Error Rate (BER) verses Signal to Noise Ratio (SNR).The polarization interleaving is used with the WDM systems to decrease the nonlinear effects and the crosstalk arising among the adjacent channels.The obtained results of the 67% RZ - DPSK arrived to the threshold power at input power less than of the 50% RZ - DPSK, as well as the 50% RZ - DPSK system arrived to maximum Q.factor lower than 33% RZ - DPSK. This is due to the pulse duration of 33% RZ - DPSK is smaller than of 50% and 67% RZ - DPSK.The results show that the coherent detection technique has better performance than the direct detection technique. The coherent detection technique has Q.factor equal to 45, while the direct detection has Q.factor equal to 27 at the same input power ( - 5dBm), while the coherent detection technique arrived to the threshold power at the input power less than of the direct detection technique.The BER of the 33% RZ - DPSK with coherent detection with 10 Gb/s at 300 km as transmission distance achieved ?10?^( - 12.9) at SNR of 10 dB, while for the 33% RZ - DPSK with direct detection is achieved a BER of ?10?^( - 8.8) with SNR of 10 dB.The performance of the proposed systems has been improved extrusivly with increase the space channel, where the performance of the systems at 200 MHz as channel spacing has best performance than 50 MHz as channel spacing.By adapting coherent detection with 33% RZ - DPSK technique of 200 MHz as channel spacing, DWDM system can carry high data rate with long - haul transmission distance.