البحث — المستودع الرقمي العراقي

المستخلص: اتصالات الالياف البصرية هي العمود الفقري للبنية التحتية للاتصالات السلكية واللاسلكية التي تدعم شبكة الانترنت. النظام الاحادي الالياف المستخدم لنقل البينات لم يعد يلبي طلب الحصول على القدرة العالية والمتنامية بشكل مستمر. هناك العديد من الطرق الممكنة لزياد | Optical fiber communication system is considered as the backbone for the infrastructure of telecommunications that handles the internet. The exponentially growing capacity is no longer satisfied by using transmission of single mode fiber. There are several possible methods for increasing transmission capacity over fixed bandwidth. These include mix many signals with optical - carrier onto a one optical fiber by achieving various wavelengths, modulation employing different amplitude levels, and two orthogonal subcarriers and polarization. An extra dimension that a fiber can offer for achieving more information is space.This project demonstrates simulation systems for Space Division Multiplexing (SDM) transmission system using Few - Mode Fiber (FMF). Polarization division multiplexing (PDM) and Dense Wavelength Division Multiplexing (DWDM) techniques are also used in this system to increase total system data rate. For the ultra - high capacity need of SDM, Few Mode Fiber (FMF) was proposed as SDM best technology for obtaining ultra - high bit rate systems with long haul transmission. Inter - mode losses that appears in higher - order - modes was the most problem to be resolved. In this thesis, the description and design of three SDM systems were explored by using both QPSK and 16QAM modulation formats : single channel SDM system with PDM technique, 8 - DWDM channels over 7 modes SDM/PDM system, and 16 - DWDM channels over 10 modes SDM/PDM system proposed as future of ultra - high capacity optical system.By using 16QAM format and bit rate per channel of 40Gb/s, the maximum long reach of our designed single channel SDM/PDM system is 1020Km. A transmission reach of 760Km was achieved for 8 - WDM - 7modes - SDM/PDM system and 260 Km for 16DWDM - 10modes - SDM/PDM. At QPSK modulation format the maximum demonstrated reach was 1460 Km for single channel SDM/PDM system. A long - haul transmission of 1080 Km was recorded for 8 - WDM channels - 7modes - SDM/PDM system and 510 Km for 16 - DWDM channels - 10modes - SDM/PDM system.The total bit rate of single channel - 3modes SDM/PDM system was 240G/s at 40Gb/s bit rate per channel. The total bit rate was achieved by using 8 - DWDM channels - 7modes SDM/PDM system is 4.48 Tb/s at 40Gb/s. The highest bit rate was achieved by using 16DWDMchannels - 10modes SDM/PDM system so that the total achieved bit rate is nearly 12.8Tb/s.Chromatic Dispersion (CD) compensator using Digital Signal Processing (DSP) was proposed to compensate chromatic dispersion losses. Frequency and phase estimators were proposed in the designed systems to remove frequency offset and phase change by using Viterbi and Viterbi algorithms.Adaptive MIMO equalizer using constant modulus algorithms was proposed to compensate deferential group delay, polarization mode dispersion, and other losses simultaneously. Numerical results demonstrated that the methods are very effective in compensating the narrow band filtering and are very robust to channel estimation noise.The demonstrated systems were designed and tested by using (VPI transmission maker v.9.5) powerful software package.SDM techniques provided us with an important source to obtain more system flexibility, scalability, and capacity.

تصميم مضاعف تناظري خطي محسن بنطاق واسع يعمل باربعة ارباع Design Of Improved Wideband Linear Four Quadrant Analog Multiplier

اسم المؤلف: رسل صلاح خضير

اسم المشرف: عبد الكريم مخيف عبيس

الموضوع العام: هندسة الكهرباء والالكترون والاتصالات

السنة: 2017

الموضوع الدقيق: هندسة الالكترونيك والاتصالات

الدرجة: ماجستير

الجامعة: جامعة بابل - كلية الهندسة - قسم الهندسة الكهربائية

اللغة: الانكليزية

مكان الجامعة: بابل

الصفحات الاولى:

المستخلص: استخدمت المضاعفات التناظرية على نطاق واسع في دوائر الاتصالات والشبكات العصبية ككاشفات للطور ومضاعفات للتردد ودوائر لمزج الاشارات والتضمين وفك التضمين. في التطبيقات التقليدية مثل دوائرالتضمين تعتبر ترددات التشغيل والسلوك الخطي للانظمة والمديات المسموح بها | Analog multipliers have been widely exploited in communication circuitries, phase detectors, neural networks, frequency multipliers, mixers, and modulation and demodulation circuits. In conventional applications, such as modulation circuits, the linearity, frequency of operation, and input voltage ranges are issues of great importance for multipliers. This work targeted these issues through the design of two types of four quadrant analog multipliers operating in wideband frequency ranges and having very high linearity with input and output voltage ranges of ±10V.The first wideband four - quadrant analog multiplier is designed using wideband squaring and operational amplifier (OPAMP) circuits. The wideband OPAMP is designed using 10 NMOS transistors based on 0.35 µm NMOS technology with supply voltages of ?12V. The wideband OPAMP has exhibited an open loop voltage gain of 3336545. The squaring circuit is built using two NMOS transistors and two wideband OPAMPs. The first wideband multiplier is built using two identical squaring circuits, two difference amplifiers, and one summing amplifier. It is characterized by high input - output linearity range of - 10 V to +10 V for both inputs, ±10 V input and output voltage ranges, and cutoff frequency of about 5 GHz. The second wideband four quadrant analog multiplier is designed using NPN bipolar junction transistors. It is built with two main circuits, which are the multiplier cell and the output circuit. The multiplier cell is built using a modified Gilbert multiplier, while the output circuit is a high gain circuit designed for changing the differential output of the multiplier cell to a single output having a voltage range of ±10 V. The multiplier circuit is designed with supply voltages of ?12 V. It is characterized by high input - output linearity range of - 10 V to +10 V for both inputs, ±10 V input and output voltage ranges, and cutoff frequency of about 1 GHz.Both multipliers are designed and tested on PSpice in ORCAD / Version 16.6.