qcn حل مشکل آنتن دهی مدلهای a700yd-a700fd

اختصاصی از اینو دیدی qcn حل مشکل آنتن دهی مدلهای a700yd-a700fd دانلود با لینک مستقیم و پر سرعت .

دانلود پروژه برابرسازی کانال در ارتباطات صوتی زیر آب با استفاده از آنتن های چندگانه

اختصاصی از اینو دیدی دانلود پروژه برابرسازی کانال در ارتباطات صوتی زیر آب با استفاده از آنتن های چندگانه دانلود با لینک مستقیم و پر سرعت .

دانلود پروژه رشته برق به زبان انگلیسی با موضوع برابرسازی (اکولایزیشن) کانال در ارتباطات صوتی زیر آب با استفاده از آنتن های چندگانه

میتوانید این پایان نامه را به زبان فارسی ترجمه کرده و با مشورت استاد راهنما به عنوان پروژه ی پایانی خودتان به ثبت برسانید

نوع فایل : Word

تعداد صفحات : 96

Contents
1. Introduction 1

1.1 Motivation and problem description 1
1.2 Literature Review 3
1.3 Thesis outline 5
1.4 Contributions 7
2. Underwater Acoustic Communication and Channel Model 8

2.1 Channel Model 8
2.2 The Baseband channel 11
2.3 FSK Signal modulation and demodulations: 18
3. Receiver and Transmitter Diversity Techniques: 21

3.1 Antenna Diversity 22
3.2 Temporal Diversity 23
3.3 Branch Combining 24
3.4 Diversity gain and failure 25
3.5 Conventional multiple antenna systems 27
3.6 Parallel stream MIMO 28
4. Review of Adaptive Equalizers 32

4.1 Linear equalization 36
4.1.1 Peak distortion criterion 38
4.1.2 Mean square error criterion 40
4.1.3 Fractionally spaced equalizer 42
4.2 Decision feedback equalization 43
4.2.1 Mean square error optimization criterion 46
4.3 Filter coefficient update methods 48
4.3.1 LMS 48
4.3.2 RLS 51
4.4 Selected experimental results 53
5 Diversity Equalization 57

5.1 Baseband communication system model 57
5.2 Joint channel equalizer (JCE) 63
5.3 Diversity with separate optimization using an independent channel equalizer (ICE) 77
6 Conclusions and Topics for Future Research 83

6.2 Further research directions 84

References 86

ABSTRACT

Currently available commercial underwater acoustic modems have been optimized for long distance communications, on the order of tens to hundreds of kilometers, trading transmission rate for increased range, reliability and robustness. However, new under-water applications are arising which do not require such long distance links. One example is the use of small fleets of closely spaced Autonomous Underwater Vehicles (AUVs) for tasks such as mine detection where the vehicle spacing is more likely to be measured in hundreds of meters at most.

This thesis investigates ways to improve transmission rates over this much shorter link. In particular, it considers the use of an additional hydrophone, currently used for navigation, to achieve diversity at the receiver. We propose an adaptive receiver structure that is capable of reliable asynchronous communication with improved efficiency.

Existing underwater acoustic equalization studies are limited to optimizing the mini-mum Mean-Square Error (MSE) jointly among all spatial diversity channels, called the Joint Channel Equalizer (JCE). In this study we propose a new sub-optimal equalizer that separately optimizes the diversity channels. We have called this the Independent Channel Equalizer (ICE). It ultimately results in a higher MSE but the system is more robust to step changes. This is beneficial to allow rapid re-establishment of communications. Re-sults are presented both in terms of the MSE and the probability of Bit Error Rate (BER). The latter is important, as it is the ultimate measure for a digital communication system.

1.   Introduction   1.1 Motivation and problem description

As technology progresses our ability to utilize and operate within the underwater environment is advancing. Once confined to merely operating on the surface we are now rap-idly exploring the depths of the oceans for military, commercial and scientific purposes.

The use of Autonomous Underwater Vehicles (AUVs) is showing great potential among many new areas of underwater research. Possible applications for this technology include dangerous and/or routine tasks such as minesweeping and reconnaissance, neither of which is suitable for human operators. However, there are many challenges that need to be addressed. These include the autonomous control of a fleet of AUVs and consequently the underwater communications required for this.

In [1,2] the problem of control algorithms for the formation flying of AUVs is considered. As part of the solution a pair of hydrophones is used to provide relative headings to aid in maintaining the formation. The presence of the two hydrophones also present possible opportunities to improve communications between AUVs, using techniques such as receiver diversity, transmitter diversity or Multiple-Input-Multiple-Output (MIMO) communications.

In this application the hydrophones are located at the bow and stern of the AUV. Due to the physical dimensions of the AUV the separation is approximately one meter. This is much closer than typical diversity receiver separations [3]. However, other researchers have shown that receiver separations as low as 0.35 meters can provide additional sources of information in the underwater acoustic channel [4].

The fading and multi-path underwater acoustic channel has always been a great impediment to building reliable underwater communication systems. Many complex physical phenomena cause the propagating acoustic wave intensity and phase to vary temporally and spatially.  Thus, one advantage of spatial diversity equalization is its ability to improve the limited signal-to-noise ratio at the receiver through coherent combining. The multi-path spread in these channels is largely caused by reflections from ocean boundaries and refraction due to sound speed variations as a function of depth. Since the degradation in the signal is caused by multi-path intersymbol interference (ISI), simply increasing the signal-to-noise-ratio will not alleviate the problem.

It is well known that coherent equalization techniques improve the bandwidth efficiency of the communication system, thus increasing the data rate [6]. Equalization techniques are well understood in radio communications [5]-[7]. A variety of equalization techniques are available, such as zero-forcing equalization, MMSE equalization, and block equalization. Decision Feedback Equalization (DFE) can be considered an effective technique because it can help to eliminate causal ISI in addition to compensating for the channel [5].

When the communication channel is unknown to the designer, adaptive equalization techniques can be used to first extract the channel response from a training sequence and then compensate the channel distortion in the incoming data symbols [7]. In this thesis the problems above are considered and a sub-optimal decision feedback adaptive equalizer with spatial diversity has been proposed and the results are compared to the optimal equalizer.

1.2 Literature Review

A general overview of the current state of underwater communications is presented in [8]. The underwater channel and its characteristics are discussed and examples of a number of communication systems of various ranges are given. It also outlines some of the current research topics, namely, receiver complexity reduction, interference cancellation and multi-user communication, system self-optimization, modulation and coding and mobile underwater communication.

Among current research a common approach to improving communication rate and reliability is to use multiple diversity channels and a jointly optimized receiver structure. Researchers have shown that for the underwater acoustic channels receiver separations as low as 0.35 meters can provide valid diversity channels [4].  In [3] a joint channel equalizer is formulated where the equalizer is optimized across all diversity channels with the receivers spaced apart in depth by between 9.4 and 55.2 meters. The separation between transmitter and receiver is 8 nautical miles.  This separation is significantly greater than any expected separation within the AUV fleet. The receiver was found to have excellent performance. However, it was computationally complex and thus a sub-optimal design was presented with much reduced complexity. This sub-optimal equalizer consisted of a set of single channel equalizers followed by a MMSE combiner. Satisfactory performance was found with a DFE equalizer composed of 25 feed-forward taps and 15 feedback taps.

آنتن

اختصاصی از اینو دیدی آنتن دانلود با لینک مستقیم و پر سرعت .

توضیحات :

از سال 1877م که نخستین آنتن ساده توسط هرتز ساخته شد. نظریه طراحی آنتن ها به سرعت پیشرفت کرده است و این پیشرفت ادامه دارد، با توجه به اینکه آنتن ها جزئی از یک سیستم مخابراتی الکترونیکی هستند، بایستی تکنولوژیست ها و مهندسین برق الکترونیک در این زمینه دانش کافی داشته باشند. امید است در این مقال اندک که در زیر به اجمال عنوان فصول آن را خواهیم آورد، قدمی هر چند کوچک در این راه برداشته باشیم .

این پایان نامه از 5 فصل تشکیل شده است. فصل اول در قالب طرح تحقیق به بررسی تاریخچه و نیز اهمیت مساله مورد تحقیق می پردازد. قابل ذکر است که اهداف ویژه تحقیق در این مساله نیز با توجه به عنوان و روش انجام این تحقیق به جای فرضیه ها و سوال های تحقیق در طرح تحقیق گنجانده شده است.

در فصل دوم به مبانی مبحث آنتن ها – انواع و پارامترهای آن پرداخته شده است . آنتن مایکروویو بوقی و مخروطی و نیز آنتن های آرایه ای از جمله آنتن های مهم مورد بحث می باشند . جهت دهندگی آنتن ، پهنای شعاع آنتن ، مقاومت پرتو افکنی آنتن ، امپدانس ورودی آنتن ، سطح موثر و طول موثر آنتن پلاریزاسیون آنتن و ... نیز از جمله شاخص ترین پارامترهای آنتن می باشند که در این فصل درباره آنها سخن گفته شده است .

 

عنوان                                                                                                                                                     

پیشگفتار                                                                                                                                                

فصل اول                                                                                                                                                               

طرح تحقیق                                                                                                                                                              

تاریخچه مختصری در باره ی موضوع تحقیق                                                                                             

اهمیت انجام تحقیق                                                                                                                                

اهداف کلی تحقیق                                                                                                                                   

هدف های ویژه  تحقیق                                                                                                                                            

روش انجام تحقیق                                                                                                                                  

فصل دوم                                                                                                                                                               

مبانی آنتن انواع و پارامترهای آن                                                                                                          

2_1: تاریخچه                                                                                                                                                        

2_2: انواع آنتن ها از نظر کاربرد                                                                                                                          

الف) آنتن هرتز                                                                                                                                                       

ب) آنتن مارکنی                                                                                                                                      

پ) آنتن شلاقی                                                                                                                                                       

ت ) آنتن لوزی ( روبیک)                                                                                                                        

ث) آنتن V معکوس                                                                                                                                 

ج) آنتن ماکروویو                                                                                                                                    

چ) آنتن آستینی                                                                                                                                                      

ح) آنتن حلزونی                                                                                                                                                      

ذ) آنتن های آرایه ای ARRAY ANTENNA                                                                        

2-3 : پارامترهای آنتن                                                                                                                                          

نمودار پرتو افکنی آنتن ها                                                                                                                     

دستگاه مختصات نمایش نمودار پرتو افکنی                                                                                           

نمودار پرتو افکنی سه بعدی و دو بعدی                                                                                                 

نمودار پرتو افکنی درفضای آزاد و در مجاورت زمین                                                                             

نمودار پرتو افکنی آنتن فرستنده و گیرنده                                                                                                           

جهت دهندگی آنتن ها                                                                                                                                             

پهنای شعاع و پهنای شعاع نیم توان                                                                                                        

شعاع های فرعی آنتن ها                                                                                                                                          

مقاومت پرتو افکنی  آنتن                                                                                                                                       

امپدانس ورودی آنتن                                                                                                                                            

سطح موثر یا سطح گیرنده آنتن ها                                                                                                            

طول موثر آنتن                                                                                                                                                        

پهنای نوار فرکانس آنتن ها                                                                                                                    

پلاریزاسیون آنتن ها                                                                                                                                              

پلاریزاسیون خطی                                                                                                                                   

پلاریزاسیون دایره ای                                                                                                                                              

پلاریزاسیون بیضوی                                                                                                                                               

ساختمان مکانیکی آنتن ها                                                                                                                       

اندازه آنتن                                                                                                                                                             

نصب آنتن ها                                                                                                                                                          

خطوط انتقال و موج برها برای تغذیه آنتن ها                                                                                           

رسانا  و نارساناهای مورد استفاده در ساختن آنتن ها                                                                             

محافظت آنتن در برابر عوامل جوی                                                                                                         

فصل سوم                                                                                                                                                              

شبکه های کامپیوتری شبکه های بی سیم                                                                                

2-1:سخت افزار شبکه                                                                                                                                         

2-1-1: شبکه های ﭘخشی(broadcast network)                                                                                

2-1-2: شبکه های همتا به همتا (peer-to-peer network)                                                  

2-1-3:شبکه های شخصی (personal area network)                                                                        

2-1-4:شبکه های محلی (local area network)                                                                  

2-1-5:شبکة شهری(Mtropolitan  Area Network)                                                                          

2-1-6:شبکة گسترده (Wide Area Network)                                                                   

2-1-7:شبکة بی سیم (wireless network)                                                                                         

2-1-8:شبکة شبکه ها (internetwork)                                                                                                               

2-2: نرم افزار شبکه                                                                                                                                            

2-2-1:لایة فیزیکی (Physical layer)                                                                                                 

2-2-2: زیر لایة نظارت بر دسترسی به رسانة انتقال ( MAC)                                                            

2-2-3:لایة شبکه                                                                                                                                 

2-2-4:لایة انتقال(Transport layer)                                                                                                 

2-2-5:لایة کاربرد (Application layer)                                                                                             

2-3: شبکه های محلی بی سیم (802.11)                                                                                            

2-3-1: ﭘشتة ﭘروتکل 802.11                                                                                                                           

2-3-2: لایة فیزیکی در 802.11                                                                                                                         

2-4: شبکه های بی سیم باند گسترده                                                                                                   

2-4-1: لایة فیزیکی در 802.16                                                                                                                         

فصل چهارم                                                                                                                                                            

آنتن های هوشمند                                                                                                                                  

 بخش اول                                                                                                                                                              

آنتن های هوشمند در شبکه های بی سیم                                                                                               

تداخل هم کانال                                                                                                                                                      

اثرات محوشدگی                                                                                                                                                     

فرمن فایل : ورد

تعداد صفحات : 102

فایل NVRAM برای حل مشکل آنتن گوشی Y511-U30

اختصاصی از اینو دیدی فایل NVRAM برای حل مشکل آنتن گوشی Y511-U30 دانلود با لینک مستقیم و پر سرعت .

فایل NVRAM برای حل مشکل آنتن گوشی Y511-U30

مخصوص ترمیم سریال و بیس باند گوشی Y511-U30

IMEI Null And Baseband Unknown Repair 100%

مخصوص MTK Droid

100% تصمینی و تست شده

آموزش رایت همراه فایل می باشد

چکیده طرح توجیهی تولید آنتن پژو

اختصاصی از اینو دیدی چکیده طرح توجیهی تولید آنتن پژو دانلود با لینک مستقیم و پر سرعت .

دانلود چکیده طرح توجیهی تولید آنتن پژو 2 ص با فرمت Pdf

فهرست مطالب:

نوع تولیدات

فرآیند تولید

ویژگی های فرآیند، نکات فنی و  شرایط عملیاتی 

مواد اولیه اصلی

ماشین الات و تجهیزات اصلی 

تعداد کارکنان 

کل انرژی مورد نیاز 

 زمین و ساختمانها