在無線通信系統(tǒng)中,信號在傳輸過程中由于多徑效應(yīng)和信道帶寬的有限性以及信道特性的不完善性導(dǎo)致不可避免地產(chǎn)生碼間串?dāng)_(Intersymbol INTERFERENCE).為了克服碼間串?dāng)_所帶來的信號畸變,則必須在接收端增加均衡器,以補(bǔ)償信道特性,正確恢復(fù)發(fā)送序列.盲均衡器由于不需要訓(xùn)練序列,僅利用接收信號的統(tǒng)計特性就能對信道特性進(jìn)行均衡,消除碼間串?dāng)_,成為近年來通信領(lǐng)域研究的熱點課題.本課題采用已經(jīng)取得了很多研究成果的Bussgang類盲均衡算法,主要因為它的計算復(fù)雜度小,便于實時實現(xiàn),具有較好的性能.本文探討了以FPGA(Field Programmable Gates Array)為平臺,使用Verilog HDL(Hardware Description Language)語言設(shè)計并實現(xiàn)基于Bussgang類型算法的盲均衡器的硬件系統(tǒng).本文簡要介紹了Bussgang類型盲均衡算法中的判決引導(dǎo)LMS(DDLMS)和常模(CMA)兩種算法和FPGA設(shè)計流程.并詳細(xì)闡述了基于FPGA的信道盲均衡器的設(shè)計思想、設(shè)計結(jié)構(gòu)和Verilog設(shè)計實現(xiàn),以及分別給出了各個模塊的結(jié)構(gòu)框圖以及驗證結(jié)果.本課題所設(shè)計和實現(xiàn)的信道盲均衡器,為電子設(shè)計自動化(EDA)技術(shù)做了有益的探索性嘗試,對今后無線通信系統(tǒng)中的單芯片可編程系統(tǒng)(SOPC)的設(shè)計運用有著積極的借鑒意義.
上傳時間： 2013-07-25
上傳用戶：cuibaigao
Abstract: Alexander Graham Bell patented twisted pair wires in 1881. We still use them today because they work so well. In addition we have the advantage ofincredible computer power within our world. Circuit simulators and filter design programs are available for little or no cost. We combine the twisted pair and lowpassfilters to produce spectacular rejection of radio frequency INTERFERENCE (RFI) and electromagnetic INTERFERENCE (EMI). We also illustrate use of a precision resistorarray to produce a customizable differential amplifier. The precision resistors set the gain and common mode rejection ratios, while we choose the frequencyresponse.
上傳時間： 2014-11-26
上傳用戶：Vici
Abstract: Class D amplifiers are typically very efficient, making them ideal candidates for portable applications that require longbattery life and low thermal dissipation. However, electromagnetic INTERFERENCE (EMI) is an issue that commonly accompanies theClass D switching topology. Active-emissions limiting reduces radiated emissions and enables "filterless" operation, allowingdesigners to create small, efficient portable applications with low EMI.
標(biāo)簽： EMI D類放大器 保持 便攜式產(chǎn)品
上傳時間： 2013-11-23
上傳用戶：哈哈hah
設(shè)計了水聲信號發(fā)生系統(tǒng)中的功率放大電路，可將前級電路產(chǎn)生的方波信號轉(zhuǎn)換為正弦信號，同時進(jìn)行濾波、功率放大，使其滿足換能器對輸入信號的要求。該電路以單片機(jī)AT89C52，集成6階巴特沃思低通濾波芯片MF6以及大功率運算放大器LM12為核心，通過標(biāo)準(zhǔn)RS232接口與PC進(jìn)行通信，實現(xiàn)信號增益的程控調(diào)節(jié)，對干擾信號具有良好的抑制作用。經(jīng)調(diào)試該電路工作穩(wěn)定正常，輸出波形無失真，在輸出功率以及放大增益、波紋系數(shù)等方面均滿足設(shè)計要求。 This paper presented a design and implementation of underwater acoustic power amplifer. This circuit converted the rectangle signal generated by frontend circuit into the sine signal， then filtered and power amplification， it meets the requirements of the transducer.Included AT89C52， 6th order Butterworth filter MF6， hipower amplififier LM12.Communication with PC through the RS232 port. The signal gain is adjustable and could be remote controlled. It has a good inhibitory effect on the INTERFERENCE signal. After debugged， this circuit works stable， the output waveform has no distortion， it meets the design requirement in outprt power， amplifier gain and ripple factor.
上傳時間： 2013-11-20
上傳用戶：qwe1234
在理論分析循環(huán)碼編碼和譯碼基本原理的基礎(chǔ)上，提出了基于單片機(jī)系統(tǒng)的(24，16)循環(huán)碼軟件實現(xiàn)編碼、譯碼的方案。仿真結(jié)果表明(24，16)循環(huán)碼能有效地克服來自通訊信道的干擾，保證數(shù)據(jù)通信的可靠及系統(tǒng)的穩(wěn)定，使誤碼率大幅度降低。本論文對(24，16)循環(huán)碼的研究結(jié)果表明，可以有效地降低錯誤概率和提高系統(tǒng)的吞吐量，實現(xiàn)糾錯僅需要在接收端增加有限的存儲空間和計算復(fù)雜度，具有一定的實用價值。 Abstract: Based on analyzing the theory of encoding and decoding of cyclic code， this paper showed the schemes of encoding and decoding of(24，16)cyclic code by the software and based on microcontroller. Simulation results show that using (24，16) cyclic codes can effectively overcome the INTERFERENCE from communication channel， ensure the reliability and stability of data communication systems， and reduce the bit error rate greatly. The results of this paper show that by using the (24，16) cyclic code， the error rate can be reduced and the system throughput can be improved. Meanwhile， the system only needs to enlarge limited storage space and computation the complexity at the receiving end to realize error correction. Thus the (24，16) cyclic code has a practical value.
標(biāo)簽： 24 16 單片機(jī)系統(tǒng) 循環(huán)碼
上傳時間： 2013-11-09
上傳用戶：gaoliangncepu
針對盤山路存在的轉(zhuǎn)彎盲區(qū)，即在轉(zhuǎn)彎時司機(jī)無法得知彎路對面是否有車輛通過，設(shè)計一種基于C8051F310的山路轉(zhuǎn)彎預(yù)防警示系統(tǒng)。該系統(tǒng)利用一階濾波算法檢測山路轉(zhuǎn)彎時是否有車輛通過。運用該算法可增強(qiáng)系統(tǒng)檢測的實時性，提高檢測機(jī)動車輛的靈敏度，同時大大減少環(huán)境溫度對檢測的干擾。試驗表明該系統(tǒng)能夠正確指示出在山路轉(zhuǎn)彎時是否有車輛通過，目前該系統(tǒng)已安裝在盤山路上，可大大減少事故的發(fā)生率。 Abstract: Aiming at passing hilly road，there is a turn blind spot.Motormen usually do not know if the passing of vehicles pass the road.So a system of defending accident on hilly road is designed,which is based on MCU C8051F310.The sys-tem uses the first-order filter algorithm to detect whether there are passing vehicles.This algorithm enhances the real-time detection and improves the sensitivity of detection vehicles.Meanwhile,it reduces the detection INTERFERENCE of environmen-tal temperature.The experimental results show that this system can exactly indicate if there are passing vehicles.At present,the system has been successfully applied to hilly road.The system can greatly decrease accident.
上傳時間： 2013-10-10
上傳用戶：歸海惜雪
介紹了一種基于C8051F020單片機(jī)的多路壓力測量儀。該測量儀選用電阻應(yīng)變式壓力傳感器采集壓力信號，并經(jīng)放大電路處理后送入C8051F020單片機(jī)，再由C8051F020單片機(jī)內(nèi)部的A/D轉(zhuǎn)換器將采集到的壓力信號進(jìn)行模數(shù)轉(zhuǎn)化，然后分別對數(shù)據(jù)進(jìn)行存儲和顯示。該測量儀能測量6路壓力信號，并且各測量點都能單獨檢測和設(shè)置。由于采用了C8051F020單片機(jī)，簡化了硬件電路，增強(qiáng)了抗干擾能力，使得測量儀具有測量精度高，沖擊小等特點。 Abstract: A measurement apparatus for multi-channel pressure based on single chip microcomputer is introduced.It can measure 6 channels signal of the pressure，and the pressure measure points can be detection and located individually.The pressure signal sampling is obtained by resistor stress-type pressure sensors，the digital signals of 6 channels are collected through amplifying and adjustment circuit of pressure signals and internal integrated A/D converter of MCU.Finally，and it realizes the function to store and display data separately.C8051F020 was used to made hardware circuit simple，and it also enhanced the anti-INTERFERENCE ability.It features high precision and little impact.
標(biāo)簽： C8051F020 單片機(jī) 多路 壓力
上傳時間： 2013-11-16
上傳用戶：yare
一種基于ST62單片機(jī)的稱重顯示控制器A Weighing Display Controller Based on ST62 Single Chip Computer祛 FA(上海時博飛奧控制系統(tǒng)有限公司，上海201100)摘要在介紹了基于ST62單片機(jī)的基礎(chǔ)上，詳細(xì)描述了稱重顯控制器的硬件設(shè)計和軟件設(shè)計思路。該控制器結(jié)構(gòu)簡單、操作方便、抗擾能力強(qiáng)等優(yōu)點;具有較好的推廣應(yīng)用價值。關(guān)鍵詞稱重顯示控制儀ST62單片機(jī)硬件設(shè)計軟件設(shè)計Abstract Ont heb asiso fin torductiono fST 62s inglec hipc omputer,th ed esignc oncrptof h ardwarea nds oftwarefo rw eighingd isplayc ontorleris d escrbed.The controler features simple structure, ease operation, powerful capability of anti-INTERFERENCE, etc.，it is wealth to be promoted into practicalapplicationsKeywords We妙噸display0 引言ST62s inglec hip Hardwared esign Softwaer design備 份 振 蕩器，振蕩器保護(hù)電路，上電復(fù)位及低壓檢測復(fù)稱 重 顯 示控制器是一種具有數(shù)字顯示、開關(guān)量輸出、定值控制和通信功能的以微機(jī)為操作核心的稱重控制裝置。它是電子衡器的重要基礎(chǔ)部件，直接影響電子衡器及電子稱重系統(tǒng)的功能和性能。與合適的傳感器及承重傳力復(fù)位系統(tǒng)組合可組成配料秤、料斗秤、定值秤、平臺秤、汽車秤等，廣泛應(yīng)用于電力、化工、建筑、冶金、交通運輸、食品、軍工等部門，是進(jìn)行自動稱重配料控制和生產(chǎn)過程自動化必不可少的重要檢測、控制裝置。隨著 稱 重 計量自動化水平的提高，對稱重顯示控制器的要求也越來越高。為實現(xiàn)低漂移、高穩(wěn)定，本控制器采用低漂移、高增益放大器AD620和高分辨率的A/D轉(zhuǎn)換器CS5550。為提高穩(wěn)定性和可靠性，采用集成度高的、抗干擾能力強(qiáng)的ST62單片機(jī)。
上傳時間： 2013-10-29
上傳用戶：釣鰲牧馬
單片機(jī)系統(tǒng)“PC”失控的軟件措施Software Measure of GettingO uto fC ontrolfo r“PC"in S ingleC hipC omputerS ystem謐 加 春 王 曉 基 雷 小 華(江 西 理 工 大 學(xué)機(jī) 電 工 程 學(xué) 院 ，贛 州 34 10 00)摘要單片機(jī)系統(tǒng)在實際工業(yè)現(xiàn)場中可能遇到各種干擾和自身的隨機(jī)性故障。現(xiàn)場惡劣的環(huán)境有可能使計算機(jī)系統(tǒng)發(fā)生異常，計算機(jī)程序指針“PC”失控就是常見的故障之一，如果發(fā)生“PC”失控，將導(dǎo)致CPI工作混亂，釀成嚴(yán)重的事故。研究了“PC”失控的原因，并指出軟件抗干擾的幾種方法，有效保證單片機(jī)系統(tǒng)的正常工作。關(guān)鍵詞單片機(jī)“PC”失控抗干擾Abstract Inp racticalin dustrialfi elds,th ereis v ariousin terferencea fectingo perationo fsi nglec hipc omputersy stemsa ndt hec omputersy stems。fac噸random faults飾themselves. It is very common that the severe environment makes the computer systems abnormal. The program counter "PC"gettingo utof co ntorlis on eo fth ec ommonfa ults.If th isoc curs,C PUw ouldb eru nningo utof or deran din torducesse riousan cient.T hec ausesof " PC"geting out of control， studied in this paper and some countermeasures of anti-INTERFERENCE師software are given to ensure single chip computer systemworking properly.Keywords Single。飾computer Porgramc ounter"P C" Anti-interfeernc 在設(shè) 計 和 開發(fā)單片機(jī)系統(tǒng)時，一般難以周全地預(yù)計單片機(jī)系統(tǒng)在實際工業(yè)現(xiàn)場中可能遇到的各種干擾和自身的隨機(jī)性故障。因此，除了采取防止和抑制干擾的各項措施外，還應(yīng)該借助于軟件措施克服某些干擾，系統(tǒng)還應(yīng)具備迅速自行恢復(fù)的能力。本文介紹的應(yīng)對單片機(jī)系統(tǒng)PC失控的軟件措施，設(shè)計靈活，節(jié)省硬件資源，能保證測控系統(tǒng)長期可靠地運行。MC S- 5 1單片機(jī)以其優(yōu)良的性能價格比大量應(yīng)用于工業(yè)現(xiàn)場測試和控制領(lǐng)域。但是，現(xiàn)場惡劣的環(huán)境有可能使計算機(jī)系統(tǒng)發(fā)生異常，計算機(jī)程序指針PC失控就是常見的故障之一，一旦發(fā)生PC“走飛”，計算機(jī)系統(tǒng)就會出現(xiàn)工作混亂，釀成嚴(yán)重的事故。為 了 在 CP 失控時盡量減少由此帶來的不利影響，并盡快使系統(tǒng)恢復(fù)正常，需要采取一定的軟件措施和硬件措施。常見的硬件措施有“看門狗”電路。軟件措施設(shè)置的前提條件是:①在干擾作用下，微機(jī)系統(tǒng)硬件部分不會受到任何損壞，或者損壞部分設(shè)置有監(jiān)測狀態(tài)可供查詢;②程序區(qū)不會受到干擾侵害。單片機(jī)系統(tǒng)的程序和表格以及重要的參數(shù)均設(shè)置在ROM區(qū)，不會因干擾的侵人而改變;③ RAM區(qū)中的重要數(shù)據(jù)不會被破壞，或者雖然被破壞，但是可以重新建立。
標(biāo)簽： 單片機(jī)系統(tǒng) 軟件
上傳時間： 2013-11-02
上傳用戶：bhqrd30
Abstract: Engineers often wish that radio susceptibility (RS) or radio immunity could be cured with an antibiotic, a vaccine, or someform of cure-all. Unfortunately, solving the RS problem is not that easy. Indeed, the laws of physics apply. In this article we discusssources of RS. We also offer tips and hints to protect systems, power supplies, printed circuit boards (PCBs), and electroniccomponents from radio frequency INTERFERENCE.
標(biāo)簽： Susceptibility Radio 無線電干擾
上傳時間： 2014-12-30
上傳用戶：旗魚旗魚
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