外文翻译 电子信息工程
最新外文文献翻译格式范例
外文文献翻译格式范例本科毕业设计(外文翻译)外文参考文献译文及原文学院信息工程学院专业信息工程(电子信息工程方向)年级班别 2006级(4)班学号 3206003186学生姓名柯思怡指导教师 ______ 田妮莉 _ __2010年6月目录熟悉微软SQL Server (1)1Section A 引言 (1)2Section B 再谈数据库可伸缩性 (4)3Section C 数据库开发的特点 (7)Get Your Arms around Microsoft SQL Server (9)1Section A Introduction to SQL Server 2005 (9)2Section B Database Scalability Revisited (13)3Section C Features for Database Development (17)熟悉微软SQL Server1 Section A 引言SQL Server 2005 是微软SQL生产线上最值得期待的产品。
在经过了上百万个邮件,成百上千的规范说明,以及数十次修订后。
微软承诺SQL Server 2005 是最新的基于Windows数据库应用的数据库开发平台。
这节的内容将指出SQL Server 2005产品的一些的重要特征。
SQL Server 2005几乎覆盖OLTP及OLAP技术的所又内容。
微软公司的这个旗舰数据库产品几乎能覆盖所有的东西。
这个软件在经过五年多的制作后,成为一个与它任何一个前辈产品都完全不同的产品。
本节将介绍整个产品的大部分功能。
当人们去寻求其想要的一些功能和技术时,可以从中提取出重要的和最感新区的内容,包括SQL Server Engine 的一些蜕变的历史,以及各种各样的SQL Server 2005的版本,可伸缩性,有效性,大型数据库的维护以及商业智能等如下:●数据库引擎增强技术。
SQL Server 2005 对数据库引擎进行了许多改进,并引入了新的功能。
电子信息工程外文翻译 外文文献 英文文献
电子信息工程电路编程中的AT89C51单片机译文标题电路编程中的AT89C51单片机AT89C51 In-Circuit Programming 原文标题作者Robert W.Sparks等译名国籍美国斯帕克等W.罗伯特Atmel Corporation原文出处摘要本应用说明的是ATMEL公司AT89C51的电路可编程闪存的微控制器。
为在电路可编程AT89C51的应用提出了与应用程序相关的例子,它的修改要求支持在线编程。
这种方法显示在该应用程序中的AT89C51单片机可通过商业电话线远程改编。
本应用笔记中描述的电路,仅支持5伏电压下编程,需要使用一个AT89C51-XX-5。
标准A T89C51的需要12伏电压。
该应用程序的软件可从ATMEL下载。
总论当不在进行程序设计的时候,在电路设计中的AT89C51设计将变得透明化。
在编程期间必须重视EA/VPP这一脚。
在不使用外部程序存储器的应用程序中,这脚可能会永久接到VCC。
应用程序使用的外部程序存储器要求这一脚为低电平才能正常运行。
RST在编程期间必须为高电平。
应该提供一种方法使得电路通入电源以后,使RST代替主要的复位电路起到复位的作用。
在编程过程中,PSEN必须保持低电平,在正常运行期间绝不能使用。
ALE/ PRO在编程过程中输出低电平,在正常运行期间绝不能使用在编程过程中AT89C5I / 端口是用于模式应用程序,地址和数据选择的,可能要该控制器从应用的电路隔离。
如何做到这一点取决于应用程序输入端在编程过程中,控制器必须与应用电路的信号来源隔离。
带有三个输出状态的缓冲区在应用程序之间插入电路和控制器,同时在编程时缓冲区输出三种状态。
一个多路复用器用于信号源之间进行选择,适用于任何一方的应用电路或编程控制器电路的信号输出端如果应用的电路可以允许端口在编程过程中的状态变化,则不需要改变电路。
如果应电路的状态,必须事先在编程过程中的保持不变,可能在控制器和应用电路中插入锁存。
电子信息工程专业毕业论文外文翻译
本科毕业设计(论文) 中英文对照翻译院(系部)电气工程与自动化专业名称电子信息工程年级班级 04级7班学生姓名指导老师Infrared Remote Control SystemAbstractRed outside data correspondence the technique be currently within the scope of world drive extensive usage of a kind of wireless conjunction technique,drive numerous hardware and software platform support. Red outside the transceiver product have cost low, small scaled turn,the baud rate be quick,point to point SSL,be free from electromagnetism thousand Raos etc.characteristics,can realization information at dissimilarity of the product fast, convenience, safely exchange and transmission,at short distance wireless deliver aspect to own very obvious of advantage。
Along with red outside the data deliver a technique more and more mature,the cost descend,red outside the transceiver necessarily will get at the short distance communication realm more extensive of application。
电子信息工程专业外文翻译--滤波器
外文原文一、a question for study or discussion1.Research background and purpose1.1 conceptualizeElliptic filter (Elliptic filter), also known as the Call filter (Cauer filter), is in the passband and stopband ripple of a filter. Elliptic filter when compared to other types of filters, in order under the same conditions with minimal fluctuations in the passband and stopband. Same as its wave in passband and stopband, which distinguish it from the Butterworth filter with flat passband and stopband and flat passband and the stopband ripple or resistance with flat, cut than the snow filter passband ripple.A low-pass filter with a frequency response range of the ellipse:Four-order low-pass elliptic filter frequency response。
1.2 scientific researchIn the low-frequency (600Hz=500KHz) commonly used in band-pass filter, large LC filters, poor stability, stability of Crystal filters, but can only be made of narrow-band filter, bad shock and vibration resistance. Active filters are small, but stability and decay characteristics are often poor, and debugging easy. Ceramic filter is poor and low-frequency seismic performance of low temperature coefficient. And than snow filter Butterworth filter transfer function is a polynomial divided by a constant, for the whole network, all zeros in infinite, only infinite stopband attenuation is infinite, and the elliptic filter in both with zeros and poles on the limited frequency. Zero ripple in the passband, that it has a minimum across the passband and stopband ripple, This is distinguished from Butterworth filter with flat passband and stopband。
关于电子信息工程的英语作文
关于电子信息工程的英语作文English:Electronic information engineering is a discipline that combines electrical engineering and computer science to develop and design electronic devices and systems for the transmission, storage, processing, and access of information. It involves the study of various electronic components, digital systems, communication networks, and computer hardware and software. Electronic information engineering is an increasingly important field as our society becomes more reliant on technology, with applications ranging from telecommunications and radar systems to consumer electronics and healthcare devices. Graduates in this field are equipped with the necessary skills to work in a variety of industries, such as telecommunications, aerospace, automotive, and healthcare, where they can design, develop, and maintain electronic systems and devices.Translated content:电子信息工程是结合电气工程和计算机科学的学科,用于开发和设计用于信息传输、存储、处理和访问的电子设备和系统。
关于电子信息工程的英语作文
关于电子信息工程的英语作文English: Electronic Information Engineering is a branch of engineering that focuses on the study and application of electronic devices and communication systems in various fields. This field combines principles from electrical engineering and computer science to design, build, and maintain electronic systems that process, transmit, and store information. Electronic Information Engineering plays a crucial role in shaping the technologies we use in our daily lives, such as smartphones, computers, telecommunication networks, and more. Professionals in this field work on developing advanced technologies like artificial intelligence, Internet of Things, and 5G networks to improve communication, automation, and data processing efficiency. With the rapid development of technology, Electronic Information Engineering will continue to evolve and pave the way for innovative solutions to various societal challenges.中文翻译: 电子信息工程是一门工程学的分支,专注于研究和应用电子设备和通信系统在各个领域。
电子信息工程毕业设计外文翻译
xx大学毕业设计外文翻译系别职业技术教育学院专业电子信息工程班级电子Z091 学号 x姓名 x指导教师 x2013年5月16日MM420 inverter energy-saving measures in the water supply system-Nanjing Hangda Yihang Technology Co., Ltd.Because the frequency conversion velocity modulation does not need to construct the tradition for the aqueous system for the aqueous system top digit water tank, the water tank, avoided two times polluting and reducing the construction investment, moreover designed reasonably can achieve the good energy conservation effect.In gives in the aqueous system, the constant speed pump only then in its highly effective section movement can guarantee the system normal work also does not have the energy dissipation.In the design, (this time current capacity is generally biggest by the pipe network most unfavorable situation, must lift is also biggest) takes the choice water pump unit the main basis, but when the pipe network current capacity reduces, the energy waste is inevitable, when also possibly creates the low current capacity in pipeline overpressure question.The water pump basis system current capacity real-time change realization stepless speed regulation movement, is solves above problem well, achieves one of energy conservation goal ways.The water pump velocity modulation may through the very many way realization, in which frequency conversion velocity modulation be the present ideal one kind.The frequency conversion velocity modulation is through will give on the aqueous system pipe network the pressure transmitter to carry on the sampling to the pipe network hydraulic pressure, transforms the pressure signal into the electrical signal, and delivers to the PID regulator and the user establishment value of pressure it carries on the comparison and the operation, finally will transform for the frequency control signal delivers to the frequency changer.The frequency changer basis transmits frequency control signal adjustment water pump electrical machinery supply frequency, thus realizes adjusts the water pump the rotational speed.May divide into two kinds according to the customer in actual use request frequency conversion velocity modulation for the aqueous system: The live pressure variable gives the aqueous system for the aqueous system and the constant pressure variable.The live pressure variable establishes for the aqueous system pressure transmitter in the service pipe net terminal, the PID regulator setting value the service flood peakvalue which needs for the pipe network terminal user.The system causes the pipe network terminal hydraulic pressure maintenance through the automatic control to be constant, causes the pipeline characteristic curve and system static lifting is invariable, but the water pump water outlet pressure changes along with the volume of diversion change according to the pipeline characteristic curve, therefore theoretically realized “the system to need how many, the unit provided how many”, could not because the volume of diversion reduced has unnecessary static lifting, the energy conservation effect was satisfied.But this is only one kind of ideal situation, also in the system only has the frequency conversion pump alone to work.Because the frequency conversion equipment quite is expensive, large-scale often uses the frequency conversion pump and the constant speed pump parallel operation way water supply for the aqueous system.Presently establishes a frequency conversion pump and a power frequency pump and the combined transport behavior example by the system in.When the pipe network current capacity reduces, needs to lift reduces correspondingly, the frequency conversion pump may through the deceleration movement realization.But also must reduce correspondingly for guarantee parallel unit normal work power frequency pump lifting, this only can through increase the current capacity realization, thus creates the water volume the dropout, also possibly causes the power frequency pump to leave the highly effective section work, namely has not achieved the true energy conservation the goal.Meets has above situation, may take following measure to improve its energy conservation effect:①Gives the aqueous system regarding the small scale, may only suppose a frequency conversion pump, and causes the pump the highly effective area (its highly effective scope to move the time scope compared to power frequency pump to want as far as possible many including to appear the probability big operating point in a big way).②Uses the multi-Taiwan pump velocity modulation movement, certainly, quite is expensive as a result of the frequency conversion speeder price, should overall evaluation its economic agent decide.③When choice power frequency pump, should cause the system when the most disadvantageous spot work, the power frequency pump operating point approaches left side of as far as possible its highly effective area; If the most unfavorable situation appears the probability to be small, may enable it to deviate slightly the highlyeffective area, falls in the highly effective area left flank.Thus, when system lifting reduces, the power frequency pump still may in the highly effective area work.The constant pressure variable is located in the water pump unit water outlet for the aqueous system the pressure transmitter, is for the purpose of causing the water pump water outlet pressure maintenance to be constant, general hypothesis for most disadvantageous operating mode when the water pump water outlet needs the value of pressure.Still by a frequency conversion pump and a power frequency pump and combined transport behavior example.When the pipe network current capacity reduces, the frequency conversion pump through the deceleration movement, maintenance lifting invariable reduces the water discharge.Because the outlet pressure is invariable, the power frequency pumps out the water volume not to be able to change (i.e. movement operating mode invariably), still in highly effective area work, thus achieves the energy conservation goal.Needs to point out, the system needs when the current capacity changes small, the water pump water outlet pressure (still for the most unfavorable situation in system needs pressure) to be bigger than the pressure which the pipeline this time needs, thus still could cause static lifting to a certain extent the waste.Following two measures may improve its energy conservation effect:①Enlarges the pipe network suitably the caliber, causes the pipeline characteristic curve to hasten gently, but this can increase the pipe network the disposable investment, needs and the energy conservation effect makes the comprehensive economical comparison.②When choice power frequency pump causes each pump the operating point to fall as far as possible on the highly effective area.For aqueous system when water used trough (for example at night), in the system the water consumption is very small, even achieved the zero current capacity, is called “the micro current capacity”.In this case, if depends upon at the highly effective area great current capacity scope movement water pump maintains the system pressure, not only buckle water pump life, moreover the efficiency is low, cannot achieve the energy conservation the goal.Theoretically, the frequency conversion pump current capacity may approach in the highly effective scope in the zero, but in fact the water pump rotational speed not impossible unlimited to reduce, only depends on the frequency conversion pump to be competent the micro current capacity operating mode with difficulty toward the dealings.The actual project uses generally when the system additionally builds the small current capacity power frequency auxiliary pump,small current capacity facilities and so on frequency conversion auxiliary pump, barometric pressure pot maintain the micro current capacity the system pressure.To the different system micro current capacity question should the special details concrete analysis, and carries on the overall evaluation to the disposable investment and the long-term operating cost to be able to make the reasonable solution.In the frequency conversion velocity modulation for in the aqueous system design process, should choose the pump reasonably according to the service pipe net characteristic, achieved in satisfies the operation requirements under the premise, both saves the goal which the investment and conserves energy.MM420变频器在给水系统的几点节能措施-南京航大意航科技股份有限公司由于变频调速给水系统不需要建造传统给水系统的高位水箱、水塔,避免了二次污染并减少了土建投资,而且设计得合理能达到较好的节能效果。
电子信息工程外文翻译--使用自适应预测和自适应算术编码的有损图像的无损压缩
中文3595字附录B 外文参考文献Lossless Image Compression with Lossy Image Using AdaptivePrediction and Arithmetic CodingSeishi Taka and Mikio TakagiInstitute of Industrial Science,University of TokyoAbstractLossless gray scale image compression is necessary in many purposes, such as medical image, image database and so on. Lossy image is important as well, because of its high compression ratio. In this paper, we propose a Lossless image compression Scheme using a lossy image generated with PEG-DCT scheme. Our concept is, send a PEG-compressed lossy image primary, then send residual information and reconstruct the original image using both the lossy image and residual information. 3-dimensional adaptive prediction and an adaptive arithmetic coding are used, which fully uses the statistical parameter of distribution of symbol source. The optimal number of neighbor pixels and lossy pixels used for prediction is discussed. The compression ratio is better than previous work and quite close to the originally Lossless algorithm.IntroductionToday there are many studies on image compression, particularly on lossy and very low bit rate compression. For image database, such high compression ratio is Important for storage and also for quick transmission,but to deal with various kinds of users demand, Lossless image transmission is indispensable.In this paper, we propose an effective Lossless compression algorithm for gray image using lossy compressed image. The lossy compression scheme uses the Joint Photographic Experts Group discrete cosine transform (PEG-DCT) algorithm as the lossy coding algorithm.First we search the similar pairs of pixels (conlexts), according to their neighbor pixels. For such pixels which have contexts,we predict their values from the contexts and the neighbors. On the other hand, for each pixel which doesn't have its context pairs, we calculate the edge level according to the difference of adjacent pixel values. For each edge level of pixels, we calculate the predictive coefficients of linear combination under the least square error criterion. Not only the pixels which havealready processed but also the pixels of the lossy image is used for prediction.For every pixel, the difference between predicted value and real value iscalculated, and the difference is converted to anon-negative value before beingencoded, according to their distribution. In entropy coding stage,we use the arithmeticcoding. It is made adaptive,and initialerror distribution is given only by one para meter, which is specific for each edgelevel's statistical distribution. The pixels belonging to the difference edge levels areencoded independently.Experimental results and good performance are shown. Like the otherLPL(L0ssy Plus Lossless) approaches, our compression ratio is less than that oforiginally Lossless scheme,but the difference is slight. Of all things, however, usersget the great merit That they can browse the image before the Losslessdecompression.Many such schemes have been proposed in the literature, but most ofthem treat the lossy image and its Lossless residual as independent symbol source.One of the exceptions is Mem on ’s algorithm[6]. We utilize the lossy datathoroughly,and much better result is obtained.1.1 Pixel estimationNormally the image data is scanned along the scan-line direction.In figure 1.current pixel is processed pixels are .Ordinal pixel estimation method predicts the NFL,value of current pixel usingPI .. .P 4 . Then calculate the prediction error e=-. Normally the linear combinationis used for prediction as follows,where TI . . .T4 are the coefficients. This Figure 1:Current pixel is the extrapolative prediction.processed neighbor pixels=c t p t p t p t p ++++44332211(1)Usually, the zero-order entropy of set {e} is lower than that of set {z}.Therefore,after entropy coding scheme such as Huffman coding[l] or Arithmetic coding[2] orLempel-Ziv coding[3], data size is reduced.Principally, we also use the linear combination like equation (1) for prediction,but the process is more adaptive than normal prediction method. And we use moreneighbor pixels (up to ten), also using the pixels of lossy image and prediction error eis converted to another form before encoding.2.1 Grouping the pixels^x x x ^Each image pixel has different property under certain criterion. From a point of image compression, grouping similar pixels and encode them together causes effectiveresult. For grouping the pixels, we use the Q value:Q=|||||pppp|pp|pp|15141312-+-+-+-(2)Using this Q value, we classify each pixel into several groups according to table 1Table 1:Grouping tableFigure 2: (a)Original image ‘Girl’and (b)JPEG compressed image(qua1ity value=5)Figure 3: (a)Image of Q value, (b)Image of prediction error of simple predictionFigure 3(a)shows the Q value and (b) shows the error of simple prediction.As canbe seen from them, the value Q correlate closely with the prediction error. Therefore the prediction coefficients are calculated independently in each group.2.2 Context searchTable 2 shows each group ’s final zero-order entropy of prediction result of image ‘Girl ’. Obviously,the upper groups are more difficult to be compressed than the lower groups. We use the context-based prediction method to deal with such upper groups.The region where we search the similar area (we denote this “context ”)is shown in figure 4. This is restricted within already processed pixels ’area. The procedure is Described below:1. Scan the area and find points that satisfy70)('>x Q and10|)()(|'<-x Q x Q (3)2. Within such points, find one that minimizes||||-||a -b |-|-||a c a b ''''a c C --+= (4)3. If the C min is smaller than 12, treat it as the context of the current point.Otherwise, return failure (not found).2.3 Prediction2.3.1 Prediction of normal groupsFor each group,we predict the value of a current pixel by linear combination of itsneighbors ’ pixel values. The coefficients are calculated by least square error method. The neighbor pixels used for prediction are shown in figure 5 (Pi ...Pia).Number ofpixels are variable (up to 10pixels), and afterwards we will choose it optimumly. The priority is shown by the suffix number in the figure. The most effective number willbe discussed later.Table 2: Group V .S. Entropy (image ‘Girl ’)Figure 4: Context-search region Figure 5: Pixels used forpredictionHere, some of the lossy pixels (RI. . .&,) got from PEG-compressed image areAlso used. Using these pixels, something like interpolative prediction is achieved.This prediction contributes the reduction of compressed size.2.3.2 Prediction of contextUnder the criterion of condition (3) and (4). a pair of context have thesimilar shapes of height. Therefore, we predict the value 2 from {a ’,b ’, c ‘, z‘, a,b, c}(see figure4). We also use the least square error estimation. The mostdifferent point from prediction of non-context pixels is, not only using the values ofneighbor pixels but also using the closest context. This scheme is effective forcontinuous edges,because nearby an edge there is a sequence of similar lookingpixels.2.4 Error conversionIf each pixel has 8 bits, the prediction error e=-can have the real numberbetween -255 and +255 (roughly). After prediction, e should be expressed as aninteger. One easy way for conversion is, simply round the value off the integer(calculate Le +0.51) and consider it as the 2’s complement 8-bit number.Our conversion algorithm is totally based on Tanigu chi ’s method[5]. After this conversion,we can also get the 8-bit non-negative integer E. First we obtainthe upper and lower bound of the group (max, min).Then, according to the figure 6,convert the actual pixel value into integer. (In this figure, if actual pixel is equal to “ax ’, E = 9.) For each group,we get the maximum and minimum pixel value andconvert the prediction error respectively. This conversion is reversible. f you get thepredicted value and the converted number E (and also upper and lower bound), youcan obtain the actual pixel value from similar numerical line.2.5 Adaptive arithmetic coding2.5.1 Fitting of the distribution of EAccording to the experimental result, the distribution of E(figure7(a)), aftererror conversion, looks very close to the right half of a Gaussian distribution:)2e x p ()2(1222f )(2σπσσx x -= (5)^x xFigure 6: Algorithm of error conversion (example)Figure 7: (a)Distribution of E (image=‘Moon ’), (b)Fitting of Ewhere the variance is 2σ.As this distribution is limited right half, 2σis equal to , where N isthe number of samples. The fitting line (estimated frequency)of E ’s distribution is Calculated )(f 22x N σ.Their graphs are shown in figure 7(b). You can see that using this Gaussian model,the distribution of E is approximated well.2.5.2 Adaptive arithmetic codingThe probability density function of this fitting curve can be expressed by only oneparameter 2σ.This distribution is used to generate the initial distribution table for encoder(and also or decoder), instead of passing the large amount of actual frequency table. For this purpose, arithmetic coding is very suitable. For this purpose, our coderis made adaptive, each symbol from the data stream renews the frequency table. By using 2σand adaptive arithmetic coder,even small amount of data is coded with high coding rate.Experimental ResultsTo generate a lossy image, we adopt the JPEG compression scheme. The reasonis that P E G is the standard scheme for still image compression and users car1 find PEG-tools easily.We use the tools named ‘cjpeg’and ‘djpeg’, which is the products of IndependentP E G Group. To create the P E G image, cjpeg -quality quality-value -optimize filename and to decompress the P E G file, djpegipeg-file is invoked. The option ’-optimize performs optimization of entropy encoding parameters. It usually makes the P E G file a little smaller. ‘djpeg’has the optionTable 3: Effect of context search (N=9, N L 4 , quality=5)‘block smooth’,which performs cross-block smoothing,but from experimental results,it made the compression ratio worse, therefore this option is not used. Parameters which are necessary for decompression are put together and also encoded by adaptive arithmetic coder. Only several percent compression is achieved, but better than doing nothing.3.1 Effect of context searchWe use three test images ‘Girl’, ‘Couple’and ‘Moon’,which are chosen from SIDBA(Standard Image Data Base).For these images, the bit rate of compressing with and without context search is compared. The results are shown in table 3. NL is the number of lossy pixels used for prediction. N is the number of Lossless neighbor pixels.3.2 Effect of the quality value on compression ratioP E G provides a fine tuning factor (quality value),which corresponds to different Qualities of the compressed images. For typical image data, a low quality value such as 20provideshigh compression with poor image fidelity. As the quality value increases the fidelity improves at the expense of compression ratio.Figure 8 shows the bit rate and quality value. As the quality value decreases, the total bit rate decreases,too. Later we use the image quality value of 5,which is enough for understanding the image roughly (see figure 2(b)).Figure 8: Bit rate V.S.Quality value Figure 9: Bit rate V.S. NL (N=10,(N=10, -9,images‘Gir1’) quality=5, image=‘Girl ’)Table 4: Result of bit rate (quality=5, N=9, NL=4)3.3 Effect of using a lossy imageThere might be a doubt that the lossy image looks similar with the original to our eyes, but differs much from a standpoint of pixel-value, therefore it hardly helps the prediction.Figure9 shows the bit rate and the number of lossy pixels used for prediction(NL).From this figure, it is known even the poor image (quality=5) helps the compression ratio considerably.There as on why the bit rate increases gradually where NL is greaterthan 4 is, that additional parameter (coefficients)is necessary for each pixel position. The optimum NL is 4. Moreover we conducted experiments to find the optimum number of N. and obtained9.3.4 Comparison with the other methodsTable 4 shows the result of the compression. Taniguchi’s method[5] is originally Lossless oriented one, therefore the results are slightly better than ours. In our method, N and NL are set optimally.MAW method is proposed by Memon[6]. It also uses a lossy P E G image toreconstruct a Lossless image. Our result is about0.5 bit/pel better than MAW, and 0.03 to 0.12 bid\pel worse than Taniguchi’s method. As the MAW’S result is given only by entropy, the difference of performance from ours might be bigger.ConclusionIn this paper, we proposed the algorithm of Lossless image compression. Unlike other literatures,we have discussed not only the entropy of residual,but how to encode it efficiently and the final size of the compressed product. This provides an attractive option in applications that have need for quick transmission on the one hand and exact Reconstruction on the other. Furthermore,using this lossy image thoroughly, the total bit rate is considerably low.Searching the contexts and using it for prediction is proved to work.We will research more effective way of using context.Our algorithm is applicable for originally Lossless oriented one (not using lossyimage). In some images,we have obtained better results than Taniguchi’s method. We are proceeding the investigation in this standpoint.We are examining if there is a more suitable algorithm for lossy compression other than P E G . And also speculating the more accurate error distribution fitting other than Gaussian model.References[11 D. A. Huffman:“A method for the construction of minimum redundancy codes”,Proceedings of IRE40,pp. 41 1420,1951[2] J. J. Rissanenet al.: “Arithmetic coding”,IBM Journalor Research and Development, 23(2),pp. 188-193,1976[3] J. Ziv and A. Lempel: “A Universal Algorithm for Sequential Data Compression”, IEEE Transactions on Information Theory,IT-23(3), pp. 337-343, May 1997 [4] Paul G. Howard and Jefferey Scott Vitter: “New Methods for Lossless Image Compression Using Arithmetic Coding”, Proceedings of Data Compression Conference ’91,pp. 257-266.199 1[5] Takayuki Taniguchietal.: “Variable-Length-Code-Selective Reversible Predictive Coding for Multi-Level Images”,The Transactions of the Institute of Electronics, Information and Communication Engineers,V ol.J70-B, pp.654-663, Jun. 1987[6] Nasir D. Memon et al.:“Simple method for enhancing the performance of lossy plus Lossless image compression schemes”, Journal of Electronic Imaging 2(3), pp. 245-252, Jul. 1993[71 DmitryA. Novik: “Compression Through Decompression into Browse and Residual Images”, Proceedings of 1993 Space and Earth Science Data Compression Workshop, NASA Conference Publication3191,pp. 7-12, Apr. 1993使用自适应预测和自适应算术编码的有损图像的无损压缩摘要多用无损灰度图像压缩是必要的,如医学图像,图像数据库等。
单片机基础毕业设计外文翻译
本科生毕业设计(论文)外文翻译毕业设计题目:外文题目:Fundamentals of Single-chip Microcomputer 译文题目:单片机基础学院:信息科学与工程学院专业班级:电子信息工程0802班学生姓名:指导教师:外文原文Fundamentals of Single-chip MicrocomputerDr. Dobbs MacintoshJournalAbstractT h e s i n gl e-chi p m i c r o com pu t er i s t h e cul m i na t i on of bo t h t h e d e v el opm e nt o f t h e di gi t al c om p ut e r a nd t h e i nt e gra t e d c i r c ui t a rgu a b l y t h e t ow m o st s i gn i fi c ant i nv en t i on s of t h e 20t h ce n t u r y .T h es e t o w t yp e s o f a rc hi t e c t u r e a r e fo un d i n s i n gl e-c hi p m i c r o com pu t e r.S om e e m p l o y t h e s pl i t p ro gr a m/d at a m em o r y o f t h e H a r v a rd a r ch i t e ct u r e, s ho wn i n F i g.3-5A-1, ot h er s f o l l o w t he p hi l o so ph y,w i d e l y a d a p t ed f o r ge n e r al-pu rp os e com p ut e rs and m i c r op r oc e s s o rs,of m ak i n g n o l o gi c al di s t i nc t i on be t w ee n p ro gr a m a n d d at a m em o r y a s i n t h e P r i n c et on ar c hi t e ct u r e.In ge n e r a l t er m s a si n gl e-c hi p m i cro c om put e r i s c ha r ac t e ri z ed b y t h e i n co r po r at i o n o f al l t h e u ni t s o f a c om put e r i n t o a s i n gl e d e vi c e.Keyword: Single-chip Microcomputer ROM RAM Programming Algorithm Features• Compatible with MCS-51™ Products• 4K Bytes of In-System Reprogrammable Flash Memory– Endurance: 1,000 Write/Erase Cycles• Fully Static Operation: 0 Hz to 24 MHz• Three-level Program Memory Lock• 128 x 8-bit Internal RAM• 32 Programmable I/O Lines• Two 16-bit Timer/Counters• Six Interrupt Sources• Programmable Serial Channel• Low-power Idle and Power-down ModesDescriptionThe AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4Kbytes of Flash programmable and erasable read only memory (PEROM). The deviceis manufactured using Atmel’s high-density nonvolatile memory technology and iscompatible with the industry-standard MCS-51 instruction set and pinout. Theon-chipFlash allows the program memory to be reprogrammed in-system or by a conventionalnonvolatile memory programmer. By combining a versatile 8-bit CPU with Flashon a monolithic chip, the Atmel AT89C51 is a powerful microcomputer which providesa highly-flexible and cost-effective solution to many embedded control applications.The AT89C51 provides the following standard features: 4Kbytes of Flash, 128 bytes of RAM, 32 I/O lines, two 16-bittimer/counters, a five vector two-level interrupt architecture,a full duplex serial port, on-chip oscillator and clock circuitry.In addition, the AT89C51 is designed with static logicfor operation down to zero frequency and supports twosoftware selectable power saving modes. The Idle Modestops the CPU while allowing the RAM, timer/counters,serial port and interrupt system to continue functioning. ThePower-down Mode saves the RAM contents but freezesthe oscillator disabling all other chip functions until the nexthardware reset.Pin ConfigurationsBlock DiagramPin DescriptionVCCSupply voltage.GNDGround.Port 0Port 0 is an 8-bit open-drain bi-directional I/O port. As anoutput port, each pin can sink eight TTL inputs. When 1sare written to port 0 pins, the pins can be used as highimpedanceinputs.Port 0 may also be configured to be the multiplexed loworderaddress/data bus during accesses to external programand data memory. In this mode P0 has internalpullups.Port 0 also receives the code bytes during Flash programming,and outputs the code bytes during programverification. External pullups are required during program verification.Port 1Port 1 is an 8-bit bi-directional I/O port with internal pullups.The Port 1 output buffers can sink/source four TTL inputs.When 1s are written to Port 1 pins they are pulled high bythe internal pullups and can be used as inputs. As inputs,Port 1 pins that are externally being pulled low will source current (IIL) because of the internal pullups.Port 1 also receives the low-order address bytes during Flash programming and verification.Port 2Port 2 is an 8-bit bi-directional I/O port with internal pullups.The Port 2 output buffers can sink/source four TTL inputs.When 1s are written to Port 2 pins they are pulled high by the internal pullups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current (IIL) because of the internal pullups.Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses (MOVX @DPTR). In this application, it uses strong internal pullups when emitting 1s. During accesses to external data memory that use 8-bit addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special Function Register.Port 2 also receives the high-orderaddress bits and some control signals during Flash programming and verification.Port 3Port 3 is an 8-bit bi-directional I/O port with internal pullups.The Port 3 output buffers can sink/source four TTL inputs.When 1s are written to Port 3 pins they are pulled high by the internal pullups and can be used as inputs. As inputs,Port 3 pins that are externally being pulled low will source current (IIL) because of the pullups.Port 3 also serves the functions of various special features of the AT89C51 as listed below:Port 3 also receives some control signals for Flash programmingand verification.ALE/PROGAddress Latch Enable output pulse for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input (PROG) during Flash programming.In normal operation ALE is emitted at a constant rate of 1/6the oscillator frequency, and may be used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to external Data Memory.If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if the microcontroller is in external execution mode.PSENProgram Store Enable is the read strobe to external program memory.When theAT89C51 is executing code from external programmemory, PSEN is activated twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory.EA/VPPExternal Access Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFFFH.Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC for internal program executions. This pin also receives the 12-volt programming enable voltage (VPP) during Flash programming, for parts that require 12-volt VPP.XTAL1Input to the inverting oscillator amplifier and input to the internal clock operating circuit.XTAL2Output from the inverting oscillator amplifier.Oscillator CharacteristicsXTAL1 and XTAL2 are the input and output, respectively,of an inverting amplifier which can be configured for use as an on-chip oscillator, as shown in Figure 1. Either a quartz crystal or ceramic resonator may be used. To drive the device from an external clock source, XTAL2 should be left unconnected while XTAL1 is driven as shown in Figure 2. There are no requirements on the duty cycle of the external clock signal, since the input to the internal clocking circuitry is through a divide-by-two flip-flop, but minimum and maximum voltage high and low time specifications must be observed.Idle ModeIn idle mode, the CPU puts itself to sleep while all the onchip peripherals remain active. The mode is invoked by software. The content of the on-chip RAM and all the special functions registers remain unchanged during this mode. The idle mode can be terminated by any enabled interrupt or by a hardware reset. It should be noted that when idle is terminated by a hard ware reset, the device normally resumes programexecution,from where it left off, up to two machine cycles before the internal reset algorithm takes control. On-chip hardware inhibits access to internal RAM in this event, but access to the port pins is not inhibited. To eliminate the possibility of an unexpected write to a port pin when Idle is terminated by reset, the instruction following the one that invokes Idle should not be one that writes to a port pin or to external memory.Figure 1. Oscillator ConnectionsFigure 2. External Clock Drive ConfigurationPower-down ModeIn the power-down mode, the oscillator is stopped, and the instruction that invokes power-down is the last instruction executed. The on-chip RAM and Special Function Registers retain their values until the power-down mode is terminated. The only exit from power-down is a hardware reset. Reset redefines the SFRs but does not change the on-chip RAM. The reset should not be activated before VCC is restored to its normal operating level and must be held active long enough to allow the oscillator to restart and stabilize.Program Memory Lock BitsOn the chip are three lock bits which can be left unprogrammed (U) or can be programmed (P) to obtain the additional features listed in the table below.When lock bit 1 is programmed, the logic level at the EA pin is sampled and latched during reset. If the device is powered up without a reset, the latch initializes to a random value, and holds that value until reset is activated. It is necessary that the latched value of EA be in agreement with the current logic level at that pin in order for the device to function properly.Programming the FlashThe AT89C51 is normally shipped with the on-chip Flash memory array in the erased state (that is, contents = FFH) and ready to be programmed. The programming interface accepts either a high-voltage (12-volt) or a low-voltage (VCC) program enable signal. The low-voltage programming mode provides a convenient way to program theAT89C51 inside the user’s system, while the high-voltage programming mode is compatible with conventional thirdparty Flash or EPROM programmers. The AT89C51 is shipped with either the high-voltage or low-voltage programming mode enabled. The respective top-side marking and device signature codes are listed in the following table.The AT89C51 code memory array is programmed byte-bybyte in either programming mode. To program any nonblank byte in the on-chip Flash Memory, the entire memory must be erased using the Chip Erase Mode.Programming Algorithm: Before programming the AT89C51, the address, data and control signals should be set up according to the Flash programming mode table and Figure 3 and Figure 4. To program the AT89C51, take the following steps.1. Input the desired memory location on the address lines.2. Input the appropriate data byte on the data lines.3. Activate the correct combination of control signals.4. Raise EA/VPP to 12V for the high-voltage programming mode.5. Pulse ALE/PROG once to program a byte in the Flash array or the lock bits. The byte-write cycle is self-timed and typically takes no more than 1.5 ms.Repeat steps 1 through 5, changing the address and data for the entire array or until the end of the object file is reached.Data Polling: The AT89C51 features Data Polling to indicate the end of a write cycle. During a write cycle, an attempted read of the last byte written will result in the complement of the written datum on PO.7. Once the write cycle has been completed, true data are valid on all outputs, and the next cycle may begin. Data Polling may begin any time after a write cycle has been initiated.Ready/Busy: The progress of byte programming can also be monitored by theRDY/BSY output signal. P3.4 is pulled low after ALE goes high during programming to indicate BUSY. P3.4 is pulled high again when programming is done to indicate READY.Program Verify: If lock bits LB1 and LB2 have not been programmed, the programmed code data can be read back via the address and data lines for verification. The lock bits cannot be verified directly. Verification of the lock bits is achieved by observing that their features are enabled.Chip Erase: The entire Flash array is erased electrically by using the proper combination of control signals and by holding ALE/PROG low for 10 ms. The code array is written with all “1”s. The chip erase operation must be executed before the code memory can be re-programmed.Reading the Signature Bytes: The signature bytes are read by the same procedure as a normal verification of locations 030H, 031H, and 032H, except that P3.6 and P3.7 must be pulled to a logic low. The values returned are as follows.(030H) = 1EH indicates manufactured by Atmel(031H) = 51H indicates 89C51(032H) = FFH indicates 12V programming(032H) = 05H indicates 5V programmingProgramming InterfaceEvery code byte in the Flash array can be written and the entire array can be erasedby using the appropriate combination of control signals. The write operation cycle is selftimed and once initiated, will automatically time itself to completion. All major programming vendors offer worldwide support for the Atmel microcontroller series. Please contact your local programming vendor for the appropriate software revision.外文资料翻译译文单片机基础摘要:单片机是电脑和集成电路发展的巅峰,有据可查的是它们也是20世纪最意义的两大发明。
电子信息工程外文翻译参考文献
电子信息工程外文翻译参考文献(文档含中英文对照即英文原文和中文翻译)译文:利用修改后的迈克耳孙干涉仪进行长度测量的初步结果摘要:基于飞秒加速器的装置,该装置建造在上海应用物理研究所(SINAP),最近一个经修改后的远红外迈克耳孙干涉仪通过光学自相关方法,已经被用来测量电子光束的长度。
相比较于之前常规的迈克耳孙干涉仪,我们使用一个空心回射器而不是一个平面反射镜的反射镜。
本文将为大家介绍实验设置和长度测量的结果。
关键词:飞秒线性加速器,长度串,干涉仪,空心回射器1 介绍最近关于电子脉冲压缩的实验产生高峰值电流和亮度飞秒电子串。
关于短束源自于高质量光束的潜在应用要求这方面一起了广泛兴趣。
高质量的核物理加速器,自由电子激光器驱动加速器,下一代线性对撞机,第四代光源都需要短时间光束脉冲。
同时,在进程中对诊断的短电子串的研究也起了重要作用。
有几种已经使用或正在开发的方法去测量短电子串的长度。
这些一般分为两类:频域方法和时域方法。
众所周知,在时域测量长度的方法中使用条纹相机,条纹相机已经证实是限于串长度超过200 fs ,此外,条纹相机昂贵并且测量系统复杂。
相对于时域测量方法,频域测量使用相干过渡辐射(CTR )从金属箔在测量飞秒脉冲的短电子中已经显现出前景。
本文我们首先从短电子串方面给出了基于一代的高强度相干渡越辐射的理论和试验研究,然后讨论该方法基于相干渡越辐射测量束飞秒的长度,并从改进电子实验装置给出了串长度测量的结果。
最后,我们分析了空气湿度对串长度测量的影响,并且阐释了对未来研究的计划。
2 理论背景2.1 相干渡越辐射源自于相对论性电子串辐射如同步加速器辐射跃迁辐射等,本质上有较广的范围,如果辐射的波长短于电子串长度,这个阶段的辐射电子不同于彼此,所以辐射是不连贯的。
另一方面,如果波长较长的串长度,辐射是连贯的并且辐射强度的平方成正比每串数字电子。
光谱强度发出一束N 粒子:11()()(1)()|()|tot I NI N N I f λλλλ=+- (2-1)这里1()I λ是靠单电子辐射的强度,()f λ是串形成因素,这是傅里叶变换的规范化的电子密度分布()S Z 。
电子信息工程外文翻译--杜比实验室谈杜比
毕业设计(论文)外文资料翻译系别:信息专业:电子信息工程班级: 081姓名:学号:附件:1.外文资料翻译译文;2外文原文指导教师评语:签名:年月日Dolby laboratory on DolbyAuthor: TigerMultichannel perceptual codingDolby AC-3is a kind of efficiency, quality and functional aspects with unprecedented effect perceptual digital audio coding technology. From the beginning of 1992, it has been for the cinema provide multichannel digital audio system and achieved in 1994into the two channel I BS application. It in the cassette and disc type family television system for transmitting multichannel digital sound function has been to the consumer electronics industry with very excited. In the United States, high definition television ( HDTV ) broadcasting the selected Dolby digital surround sound transmission, estimated that in 1996will be put into a test screening.Many have been announced and the potential applications of the technology of test shows, Dolby AC-3decoder has a beautifully versatility. AC-3 is not a single machine system, but a kind of use can make such as bit rate and number of channels such parameters to adapt to different special application flexible procedures for the treatment of familial. Various types of all decoder in order to work on the same principle as the foundation, and designed to take full account of the future need for compatibility and adaptability. Important is, Dolby AC-3will be high quality sound and excellent digital efficiency is very perfect combination. Because of the Dolby Laboratory for more than 20 years focus on human auditory research, in the development of signal processing field has accumulated rich experience, so, although AC-3than in the CD disk to the last channel lower bit rate to create a multi-channel surround sound, however, it makes the sound quality fully meet the listener expectations.Audio : past present and futureIn 30, the famous Baer Laboratories began using the three channel stereo sound. In 50, when the stereo into public movie, it uses the channel in four above, sometimes reaching over seven channels. A few years later, the stereo into families, since all of the phonograph records only with dual channel matching, so the family leave acoustic device only by dual channel playback, the technical limitations, can not the listener will generally two-channel stereo as the home audio selection criteria.But the film makers have channel 1( left, right, center ) and surround channel2as a compelling vivid sound minimum requirements. This can be from 70 time end, eighty time period the film industry widely adopted Dolby stereo to record film confirmed, Dolby stereo is the principle, let four channel matrix coding input two optical sound track, then an appropriate audio processor will restore it into four channels matrix coding reproduction.When Dolby stereo film is converted into audio signals, four channel coding retained the dubbing integrity, from 80 time begin first, Dolby surround has made multiple channel decoding into family time, today, tens of thousands of home audio systems are equipped with Dolby surround sound system, in fact, multi-channel surround sound system sales has been farbeyond the two-channel stereo system sales, at present, Dolby surround sound has been widely used in film, TV and music on CD recording studio, and its accompanying family Dolby surround systems on the market rapid development.With multi-channel audio in consumer electronics in the field of rapid growth, a more advanced technology was born, the technology is born there is nothing comparable to this, it has simulated realistic sound effects, and can satisfy various listening conditions and high demand cannot imagine adaptability, this is Dolby AC-3decoding technology Dolby AC-3 decoder, the successful development and application, is the world's electro-acoustic industry a major achievement.Dolby AC-3In 1987, high-definition television channel in the United States has officially become the standard process, its audio track is used for the first time in the four channel matrix encoding conversion for transmission of digital code stereo. However, by 1990, in order to avoid audio matrix are affected, four mono or stereo combined configuration as the optimal configuration. Due to time technical limitations, such an arrangement would have to increase by at least a bit rate.It is in this context, Dolby AC-3was born. It has the advantage of only two independent stereo more code rates can realize multi-channel audio code. Dolby advanced to the transmission of the code technology, such as Dolby AC-2 decoder for Dolby AC-3's successful development paved the way, but the complexity of multichannel code also need further research, including a new type of bit allocation technique.The Dolby laboratory is established by Rui Milton Dolby. Dr. Dolby was born in 1933 in the United States Portland Oregon City, grew up in the San Francisco Bay area. At the age of 16 he was still in high school, in Ampex company works. The company is the United States 's first production of magnetic tape recording equipment manufacturers. Later, he is responsible for the development of the company developed the world's first practical VCR portion of an electronic circuit.In 1957 Dolby graduated from Stanford University, University of Cambridge, Marshall won the British provided scholarships, study of L-band X light. In 1961 he received a doctor's degree in physics. In 1963, he accepted the UN appointed to India as a two-year consultant.As an amateur recording enthusiasts, Dr. Dolby over the years to recognize on the tape recording audio or video signal when background noise on the recording quality damage. While in India he began thinking seriously about a noise reduction without compromising the recording quality approach. His exploration of these became the Dolby A B noise reduction and noise reduction, noise reduction system based on C.In 1965, returning to England, in London he established his own laboratory in order to carry out in India he thought scheme. Set up in 1968 to" the Dolby lab" named company. Although the company was founded10 years ago, the work of the centre in the UK, but it has been an American company. After 1976, the company's main work moved to San francisco.In 1965, the first Dolby A type noise reducer ( A representing audio Audio ) production out of. The design of the system for a variety of audio noise reduction application, especially can solve the studio recording tape when the tape recorder generated noise. Until 1966, there have beenseveral noise reducing technology available, but they are much to damage the recording quality. So Dr Dolby faced difficulty is how to make the personage inside course of study and potential customers to believe his technique. At that time, multitrack recorder, from the 4 rail, track 8, track 16to 24 track, start the application, when multitrack recording tape audio mixing, the mixing of the two track tape noise level than double direct recording of the master tape is much higher.In 1966January, Decca Records UK Department believes that Dolby A type noise reducer can indeed as Dr. Dolby described that play a role, and then ordered9Dolby A301A type noise reducer, applied for the first time in 1966May in Vienna to record Ashe Ken that Qi played some of Mozart's piano concerto. In 1966November, Decca published the first application of Dolby A type noise reducer record by Georg Solti / Muller second symphony. Subsequently, the recording industry began to recognize and use a large amount of Dolby A type noise reduction system. Initially used only recorded classical music, when multitrack recording technology promotion, will be more widely applied. Soon, the whole world of professional and non-professional begin to" Dolby" with high quality recording together.With the hope that Dolby will be present and noise reduction technology for civilian recorder voice rising, in an American commercial tape recorder manufacturer KLH company 's urging,1967April Dolby lab started to develop more practical civil noise reduction technology, initially known as the" simplified Dolby system", which later became known as Dolby B type noise reduction technology. In the Dolby B noise reduction technology development is nearing completion, Dr. Dolby made the decision, Dolby laboratory will not civilian production of audio products, consumer electronics products, but to the manufacturers authorized Dolby technology has been very mature, then by manufacturers for production. By the end of 1974, the Dolby laboratory authorized manufacturers already amounted to 47, including all consumer audio equipment manufacturers.Thereafter, Dolby laboratory has developed a series of Technology: C type noise reduction, SR ( spectral recording ), S type noise reduction, HXPro, stereo surround Dolby, Dolby, Dolby Pro Logic, AC1, AC2, Dolby digital ( AC3), Dolby E. These techniques are widely used in civil and professional audio equipment, sound recording film, cinema playback apparatus, digital broadcast etc..In addition to the headquarters in San Francisco, Dolby laboratory at present in the world have established branches or liaison offices: Losangeles, Wootton Barcelona ( UK), London, Brisbane, New York, Tokyo, Shanghai, Beijing, Hongkong.AC-3 multi-channel frameDolby surround ( Dolby Surround ) is the original Dolby multichannel film analog format consumer version. In the production of Dolby surround sound, a 4Channel -- left, right, and surround sound channel audio information through matrix coding in two tracks on a record. The two tracks from stereo format program source such as a video and television broadcast program and carrying into the family, and decoded the original 4channels of information can be reduced and surround sound. Hundreds of thousands of home videos and TV shows by Dolby surround coding." Dolby surround ( Dolby Surround ) as the most primary surround sound standard, provides a 4channel surround sound support.Dolby surround and DTS surround is similar in that they are lossy digital compression technology. This is referred to as" emotional" data compression technique is based on the human psychoacoustics that possess sound characteristics -- for high level sensitive voices, while shielding the other is not sensitive to the sound development of.Because Dolby stereo is a coding technology of digital stereo, and decoding technique uses a direction identifying circuit or a directional logic circuit, so that the use of Dolby company this circuit technology of sound is called Dolby Pro Logic sound; with Dolby 's proprietary specific decoding technology is called a Dolby Pro logic decoder decoder.Of course, only with the use of Dolby to the logic function of the AV amplifier, played by Dolby sound recording software, can hear the true high fidelity digital stereo sound effect. Dolby digital systems will generally be5.1 channel sound compression to 384bps, and some CD with 448bps, the maximum to the 640bps; DTS usually use much larger bit rate --1536bps. If other conditions are the same, is a bit more quality is better, this assertion is wrong? Unfortunately, the answer to this question is not so easy, because the Dolby Digital ( abbreviated as DD ) and DTS data compression circuit is different. For example, a coding efficiency very low signal, even if the bit rate is very high, also just wasted bits and disc space, but does not improve sound quality. Once a system is said to be" transparent", increase the bit rate without causing it to improve the sound quality. In addition because the DTS bit rate higher than Dolby, need takes up more space, if the DVD disk capacity constraints, may produce adverse effects on image quality, or to increase the additional cd.Dolby Pro-Logic surround sound ( Dolby Pro Logic ) is Dolby developed a surround sound system. It is the four track stereo recording by a specific encoding means for the synthesis of two channel, the original left channel ( L ), the right channel ( R ), the center channel ( C ), surround channel ( S ) of the 4signal, encoded into LT, RT composite double channel signal, replay through the decoder will encoded two-channel composite signals LT and RT reduction for encoding the left, right, in around four, each stem and independent signal, amplified respectively input left, right, center and surround sound speakers.In order to playback symmetry reasons, surround speakers using the left and right surround speakers, respectively, from the output of the amplifier, so the business to Dolby Pro-Logic surround sound output called channel five. But due to a left, right surround sound speakers connected in a channel, the output is the same as the surround channel information, the essence is still four channel. The business also has six channels and seven channels Dolby Pro Logic AV amplifier. The six track is the central channel two amplifying circuit is respectively connected with the output, in left center speaker and right center speaker. But left, right center speaker connected to a center channel, it is essentially a four channel. Seven channel surround sound channels is divided into four channel output, i.e. left rear surround, right rear surround sound, and adopts four surround sound, which became a seven channel output. But the output of the seven track four surround speakers are connected in a surround channel, also can calculate the output of four sound channels. So with Dolby Pro logic decoder AV amplifier whether five channel output, six channels of output or the seven output channels, is essentially a four channel. Dolby Pro-Logic surround sound in the left, right, three channel frequency range can reach 20-20000Hz, can meet the full range of requirements, but surround channel frequency range is narrow, only 100-7000Hz.Dolby E is designed for digital TV broadcast and post-production and the design of aprofessional audio coding system. Using the Dolby E, a AES / EBU channel can send up to 8channels of high quality digital audio stream, and also can be loaded Dolby digital control data signals (often called the metadata, including the Dolby digital mono mode, dynamic range, type, output level automatic adjustment of parameters, to ensure that users can correct Dolby digital program ). Dolby E with its advanced coding algorithm and higher data transmission rate, can ensure the digital TV audio signals through as many as 10cycle coding - decoding or other editing process, and does not cause quality deterioration. Dolby E audio can be associated with various formats of video signal is a good match, won't because video interference blind audio, sound burr or other distortion. Dolby E audio and video frames in the sequence are completely corresponding, can achieve precise audio and video integrated editing. More importantly, by use of this new type of coding technology, the existing radio and television system without large-scale transformation can spread multi-channel digital TV audio signals, thereby greatly reducing the system cost.Dolby E application is in digital television stations intermediate transfer, from a local television program transmitted by satellite to another local TV station. Dolby E in conveying to the transmitting terminal will be converted to PCM audio, and then encoded into Dolby digital signal, transmitted to thousands of households. Therefore, consumers in the home can be directly received by Dolby E signal, but only receives a digital signal on channel 5.1Dolby. In order to avoid the confusion, usually Dolby E called transfer coding system, and Dolby will be called to launch digital coding system.Dolby E standard data transfer rate is 1.92Mbits / sec (20bit / 48kHz for audio signal ), typical operating mode is "5.1+2", using six channel transmits a 5.1channel surround sound signal, the other two channel transmission of two-channel matrix coding signal ( such as Dolby Pro-Logic surround sound ) or dual mono stereo signal. Can also work in other modes, such as with two mono signal"5.1+1+1" pattern, three way stereo signal "3x 2" mode and a six single channel signal"6x 1" mode. Dolby's current version supports 29.97fps frame rate ( NTSC standard, PAL25FPS ),20bit length and 48kHz sampling frequency of the audio signal, a future version will support25FPS,16bit or24bit audio signal.AC-3 transmission formAC-3 based transmission system into a more extensive application field is feasible in technology. At the end of the century before, several AC-3 based application technology into commercial production.High definition television ( HDTV ) is declared using a AC-3 code first application technology. Grand Alliance has selected the United States developed this technique. For its high definition television system with digital surround sound and in 1996Atlanta Olympic Games for the first time as media.Because the AC-3effects and can be associated with high definition television matches the standard features of digital cable TV system, therefore, is a natural candidate for AC - 3. The first test transmission was 1994year. Due to the current available programs can use a single sound, stereo can also use with matrix ( matrix - sur-round ) stereo, therefore, a AC-3dual channel decoder for has been developed. And when the multi-channel digital program for transmission, high function converter ( converter ) will create a synthetic stereo downwardmixing effect.Always as home theater the highest quality image source DVD ( (LD ) as Dolby surround digital multi-channel audio examples show. Using AC-3bit stream ( bit stream ) alternative FM channel in a channel, so that the stereo pulse code modulation ( PCM ) digital audio soundtrack with FM mono cooperate with each other, so that it can be compatible with existing any player. With cable, DBS and DAB is realized by AC-3spectrum effect, quality and multi channel features a unique mix of choice. The first use of AC-3DBS system has been introduced in 1994, it can be for commercial organizations to provide a single transmitter transmission up to 120 stereo music channel transmission system.Other areas of application include medical telemetry devices suitable for very low bit-rate code under development. Potential users and system developers and the Dolby laboratory, in order to obtain the AC-3 technical support.AC-3 integrated circuitDolby surround digital main technical progress is Rolland ( Irap ) Company IR38000, which is a can perform AC-3decoder to decode single chip digital sound field processor ( DSP ). It was first used in second generation Dolby stereo digital cinema in the decoding unit.A Rolland company development, lower cost, especially suitable for consumer electronics equipment and also can provide the program logic decoding ( Pro Logic decoding ) AC--3 decoder integrated circuit in the middle of 1994launch. This is a dual channel integrated circuit chip can be used, such as cable television 's top decoder. Other semiconductor manufacturers have been or are ready to supply the AC-3 decoder integrated circuit.Dolby and digitalAC-3 is Dolby's laboratory developed the third generation of perceptual coding system. Each code system will be a special psychological acoustics ( psycho acoustics ) knowledge and advanced digital signal processing technology combine very well.AC-1 initially by the Australian Broadcasting Corporation in 1985 for its DBS system. Perhaps partly because AC-1 decoder cost reasons, it appears to be widely applied to other DBS services, satellite communication network and digital" wired broadcasting system". According to their different applications, each channel code rate for 220-325bit / sec. As an adaptation of delta modulation ( ADM ) in the form of a digital stream, ( datastream) contains information not by audio signal absolute value provided, but by different sampling ( Sample ) value changes identified. By Dolby transform to noise reduction techniques, such as: continuous transformation step and pre-emphasis can greatly improve the adaptation of delta modulation ( ADM ) basic performance.Dolby AC-2advanced adaptive transmission code used in professional audio transmission and storage, which each channel digital rate of 128 or192day / sec. Narrow band multiplicity of frequency control signal program fully adopted the noise masking superiority, resulting in an efficient reduction rate and high signal transparent effect. In other applications, such as: a long distance transmission, real time (real-time ) recording, mixing and adding storage ( ADR ) are very widely used for connecting remote recording studio or film shooting field. AC =3 is alsoused to connect the BBC Transmitter Room and the Dolby DSTLR system core equipment. AC-3 is in the AC-1and AC-2is developed on the basis of multi channel coding technology, to retain the original AC - 2such as window function, exponential transform coding, adaptive bit allocation and many other features, but also a new stereophonic sound channel coding technology strategy for the coupling and rematrix algorithm. In general, the stereo left channel and a right channel signal in the sense of hearing is very similar, there are many repetitive redundancy information, will be the two channel signals combine to be coded, can remove redundant signal and will not affect the original sound quality. Here AC-3array low bit rate and an effective means of.AC-3PC voice data input, output the compressed digital bit stream. Coding is the first step, using the TDAC ( Time Domain Aliasing Cancellation ) filter the time-domain PC sampling data is transformed into a frequency domain blocks into a series of transform coefficients, each transform coefficient in binary exponential notation, namely an exponent and a mantissa. Exponent part encoded constitutes the entire signal substantially the spectrum, also known as the spectral envelope. Using the spectrum including and shaded by line correlation decision each mantissa bit allocation. Because the bit allocation is adopted in the anterior / posterior to the hybrid adaptive bit allocation and public bit pool technology, which can make the limited rate in the channel between the different frequency components, between the rational allocation of the mantissa; in quantization process, the mantissa is shaking, shaking the pseudo random number generator can be on a different platform to get the same results. By the end of six blocks of the spectral envelope, coarse quantization of the mantissa and the corresponding parameters consisting of AC-3 data frame format, continuous frame merged into a digital stream output.By the time domain is transformed to the frequency domain block length selection is the exponential transform coding based on. As defined in AC-3two length switching, a512sample value point of the long block, a256sample value point of short block. In the analysis of signal spectrum, to deal with the channel signal blocks cut made longer, so that you can get a better frequency resolution, but also can get higher coding efficiency. But long data block may contain a number of different possible recognition of noise, such as pre-echo. That is to say the ear due to time and frequency exists on the shadowing effect in the exponential transform coding is a contradiction, not at the same time, must plan as a whole processing. For the steady state signal, whose frequency varies with time transform slow, in order to improve the coding efficiency, requirement filter has good frequency resolution, which requires a long block; as for the rapidly changing signal, requires good time resolution, which requires a short block. In the encoder, the input signal after3Hz high-pass filter removes the DC component, and then through a8kHz high-pass filter out high-frequency components, with its energy are compared with a preset threshold, in order to detect the signal transient situation.AC-3based on the modified discrete cosine transform ( MDCT ) adaptive transform coding ( ATC ) algorithm. Although defined in AC-3 standard MDCT transform, but the actual using a N / 4IFFT ( FFT ), plus two simple Pre-IFFT and Post-IFFT as adjustment, in order to achieve a N IMDCT transform. ATC algorithm is an important consideration is based on auditory masking effect critical band theory, namely in the critical band within a voice to another voice signal shielding effect the most obvious. Therefore, dividing the band filter group to have fast enough to ensure that critical band frequency response, and noise attenuation is large enough,the time and frequency of noise within the defined in the masking threshold.The AC-3 encoder bit allocation technique, has been applied widely on the forward and backward adaptive bit allocation rule. Forward adaptive bit allocation method is the encoder calculation, and the bit allocation information explicitly incorporated into the stream of data bits, and is characterized in that the front end of the encoding process uses auditory model, thus modifying the model the receiving side decoding process has no effect; the disadvantage of reducing coding efficiency, because of the need to transfer the bit allocation information while occupying a part effective bits. To the adaptive method did not get encoder clear bit allocation information, but from a digital stream in which the bit allocation information, has the advantages of no occupation of the effective bits, thus has higher transmission efficiency. Its drawback is from received data to calculate the bit allocation, if the calculation is too complex to the rising cost of decoder. In addition, the decoder algorithm also with encoder auditory model change. AC-3using hybrid backward / forward adaptive bit allocation, in enhancing the rate and reduce the cost of strikes a balance between.AC-3 decoder decoding principle basically is encoded by the reverse process, firstly, the decoder must with the encoded data stream synchronization, and then from a data error correction of digital flow separation control data, system configuration, the encoded spectral envelope and the quantized mantissas and other content, according to the sound spectrum envelope to generate the bit allocation information, the mantissa part of inverse quantization, restoring the transform coefficient exponent and mantissa, after synthesis filter banks, the data from the frequency domain to time domain, the final output of the PCM sample signal reconstruction.Through the understanding of AC-3, you can see the AC-3technology makes full use of the human ear sensory model, according to the different properties of signal, to take the corresponding effective algorithm, achieved at a high quality under the premise of achieving a higher rate for the intended purpose, is a very efficient and economical digital audio compression system. AC-3 is the American digital television system of mandatory standard, is the European digital television system recommended standard, at the same time, AC-3or DVD system of compulsory standards. At present our country is the development and promotion of digital TV system, all have reasons to believe that AC-3 technology will have a good prospect of application.Dolby Chun chamber ( About DolbyLaboratoies ) from the analog noise reduction ( analog noisereduction ) to the digital code ( digitalcode ), Dolby has concentrated on rooted in laboratory to ear sound perception based audio processing development. In the process of development, Dolby has always been the emphasis is on the critical listening and tested. Either analog or digital program program, their results are the same, with low cost, greatly improves the efficiency of communication media. In some cases, it also for the improvement of new products, such as: Dolby surround sound ( DolbySurround ) and home theater ( home theater T ) make contribution.The Dolby laboratory consists of the following components: investment and Technology Development Engineering Department, occupation audio product design and manufacturing sector, experts the organization and distribution of all over the world in the field of support group. Dolby products from companies located in modern American and British manufacturing plant. Lyrics by the world's major consumer electronics manufacturers group; for each license。
电子信息毕业设计外文翻译--微型计算机控制系统(单片机控制系统)
毕业设计外文资料翻译Graduation design foreign language translation学院:电气工程与自动化学院专业班级:电子信息科学与技术三班学生姓名:学号:指导教师:外文资料:Microcomputer SystemsElectronic systems are used for handing information in the most general sense; this information may be telephone conversation, instrument read or a company‟s accounts, but in each case the same main type of operation are involved: the processing, storage and transmission of information. in conventional electronic design these operations are combined at the function level; for example a counter, whether electronic or mechanical, stores the current and increments it by one as required. A system such as an electronic clock which employs counters has its storage and processing capabilities spread throughout the system because each counter is able to store and process numbers.Present day microprocessor based systems depart from this conventional approach by separating the three functions of processing, storage, and transmission into different section of the system. This partitioning into three main functions was devised by V on Neumann during the 1940s, and was not conceived especially for microcomputers. Almost every computer ever made has been designed with this structure, and despite the enormous range in their physical forms, they have all been of essentially the same basic design.In a microprocessor based system the processing will be performed in the microprocessor itself. The storage will be by means of memory circuits and the communication of information into and out of the system will be by means of special input/output(I/O) circuits. It would be impossible to identify a particular piece of hardware which performed the counting in a microprocessor based clock because the time would be stored in the memory and incremented at regular intervals but the microprocessor. However, the software which defined the system‟s behavior would contain sections th at performed as counters. The apparently rather abstract approach to the architecture of the microprocessor and its associated circuits allows it to be very flexible in use, since the system is defined almost entirely software. The design process is largely one of software engineering, and the similar problems of construction and maintenance which occur inconventional engineering are encountered when producing software.The figure1-1 illustrates how these three sections within a microcomputer are connected in terms of the communication of information within the machine. The system is controlled by the microprocessor which supervises the transfer of information between itself and the memory and input/output sections. The external connections relate to the rest (that is, the non-computer part) of the engineering system.Fig.1-1 Three Sections of a Typical Microcomputer Although only one storage section has been shown in the diagram, in practice two distinct types of memory RAM and ROM are used. In each case, the word …memory‟ is rather inappropriate since a computers memory is more like a filing cabinet in concept; information is stored in a set of numbered …boxes‟ and it is referenced by the serial number of the …box‟ in question.Microcomputers use RAM (Random Access Memory) into which data can be written and from which data can be read again when needed. This data can be read back from the memory in any sequence desired, and not necessarily the same order in which it was written, hence the expres sion …random‟ access memory. Another type of ROM (Read Only Memory) is used to hold fixed patterns of information which cannot be affected by the microprocessor; these patterns are not lost when power is removed and are normally used to hold the program which defines the behavior of a microprocessor based system. ROMs can be read like RAMs, but unlike RAMs they cannot be used to store variable information. Some ROMs have their data patterns put in during manufacture, while others are programmable by the user by means of special equipment and are called programmable ROMs. The widely used programmable ROMs are erasable by means of special ultraviolet lamps and are referred to as EPROMs, short for Erasable Programmable Read Only Memories. Other new types of device can be erased electrically without the need for ultraviolet light, which are called Electrically Erasable Programmable Read OnlyMemories, EEPROMs.The microprocessor processes data under the control of the program, controlling the flow of information to and from memory and input/output devices. Some input/output devices are general-purpose types while others are designed for controlling special hardware such as disc drives or controlling information transmission to other computers. Most types of I/O devices are programmable to some extent, allowing different modes of operation, while some actually contain special-purpose microprocessors to permit quite complex operations to be carried out without directly involving the main microprocessor.The microprocessor processes data under the control of the program, controlling the flow of information to and from memory and input/output devices. Some input/output devices are general-purpose types while others are designed for controlling special hardware such as disc drives or controlling information transmission to other computers. Most types of I/O devices are programmable to some extent, allowing different modes of operation, while some actually contain special-purpose microprocessors to permit quite complex operations to be carried out without directly involving the main microprocessor.The microprocessor , memory and input/output circuit may all be contained on the same integrated circuit provided that the application does not require too much program or data storage . This is usually the case in low-cost application such as the controllers used in microwave ovens and automatic washing machines . The use of single package allows considerable cost savings to e made when articles are manufactured in large quantities . As technology develops , more and more powerful processors and larger and larger amounts of memory are being incorporated into single chip microcomputers with resulting saving in assembly costs in the final products . For the foreseeable future , however , it will continue to be necessary to interconnect a number of integrated circuits to make a microcomputer whenever larger amounts of storage or input/output are required.Another major engineering application of microcomputers is in process control. Here the presence of the microcomputer is usually more apparent to the user because provision is normally made for programming the microcomputer for the particular application. In process control applications the benefits lf fitting the entire system on to single chip are usually outweighed by the high design cost involved, because this sort lf equipment is produced in smaller quantities. Moreover, process controllers are usually more complicatedso that it is more difficult to make them as single integrated circuits. Two approaches are possible; the controller can be implemented as a general-purpose microcomputer rather like a more robust version lf a hobby computer, or as a …packaged‟ system, signed for replacing controllers based on older technologies such as electromagnetic relays. In the former case the system would probably be programmed in conventional programming languages such as the ones to9 be introduced later, while in the other case a special-purpose language might be used, for example one which allowed the function of the controller to be described in terms of relay interconnections, In either case programs can be stored in RAM, which allows them to be altered to suit changes in application, but this makes the overall system vulnerable to loss lf power unless batteries are used to ensure continuity of supply. Alternatively programs can be stored in ROM, in which case they virtually become part of the electronic …hardware‟ and are often referred to as firmware. More sophisticated process controllers require minicomputers for their implementation, although the use lf large scale integrated circuits …the distinction between mini and microcomputers, Products and process controllers of various kinds represent the majority of present-day micro computer applications, the exact figures depending on one‟s interpretation of the word …product‟. Virtually all engineering and scientific uses of microcomputers can be assigned to one or other of these categories. But in the system we most study Pressure and Pressure Transmitters. Pressure arises when a force is applied over an area. Provided the force is one Newton and uniformly over the area of one square meters, the pressure has been designated one Pascal. Pressure is a universal processing condition. It is also a condition of life on the planet: we live at the bottom of an atmospheric ocean that extends upward for many miles. This mass of air has weight, and this weight pressing downward causes atmospheric pressure. Water, a fundamental necessity of life, is supplied to most of us under pressure. In the typical process plant, pressure influences boiling point temperatures, condensing point temperatures, process efficiency, costs, and other important factors. The measurement and control of pressure or lack of it-vacuum-in the typical process plant is critical.The working instruments in the plant usually include simple pressure gauges, precision recorders and indicators, and pneumatic and electronic pressure transmitters. A pressure transmitter makes a pressure measurement and generates either a pneumatic orelectrical signal output that is proportional to the pressure being sensed.In the process plant, it is impractical to locate the control instruments out in the place near the process. It is also true that most measurements are not easily transmitted from some remote location. Pressure measurement is an exception, but if a high pressure of some dangerous chemical is to be indicated or recorded several hundred feet from the point of measurement, a hazard may be from the pressure or from the chemical carried.To eliminate this problem, a signal transmission system was developed. This system is usually either pneumatic or electrical. And control instruments in one location. This makes it practical for a minimum number of operators to run the plant efficiently.When a pneumatic transmission system is employed, the measurement signal is converted into pneumatic signal by the transmitter scaled from 0 to 100 percent of the measurement value. This transmitter is mounted close to the point of measurement in the process. The transmitter output-air pressure for a pneumatic transmitter-is piped to the recording or control instrument. The standard output range for a pneumatic transmitter is 20 to 100kPa, which is almost universally used.When an electronic pressure transmitter is used, the pressure is converted to electrical signal that may be current or voltage. Its standard range is from 4 to 20mA DC for current signal or from 1 to 5V DC for voltage signal. Nowadays, another type of electrical signal, which is becoming common, is the digital or discrete signal. The use of instruments and control systems based on computer or forcing increased use of this type of signal.Sometimes it is important for analysis to obtain the parameters that describe the sensor/transmitter behavior. The gain is fairly simple to obtain once the span is known. Consider an electronic pressure transmitter with a range of 0~600kPa.The gain isdefined as the change in output divided by the change in input. In this case, the output is electrical signal (4~20mA DC) and the input is process pressure (0~600kPa). Thus the gain. Beside we must measure Temperature Temperature measurement is important in industrial control, as direct indications of system or product state and as indirect indications of such factors as reaction rates, energy flow, turbine efficiency, and lubricant quality. Present temperature scales have been in use for about 200 years, the earliestkPamA kPa mA kPa kPa mA mA Kr 027.0600160600420==--=instruments were based on the thermal expansion of gases and liquids. Such filled systems are still employed, although many other types of instruments are available. Representative temperature sensors include: filled thermal systems, liquid-in-glass thermometers, thermocouples, resistance temperature detectors, thermostats, bimetallic devices, optical and radiation pyrometers and temperature-sensitive paints.Advantages of electrical systems include high accuracy and sensitivity, practicality of switching or scanning several measurements points, larger distances possible between measuring elements and controllers, replacement of components(rather than complete system), fast response, and ability to measure higher temperature. Among the electrical temperature sensors, thermocouples and resistance temperature detectors are most widely used.DescriptionThe AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K bytes of Flash programmable and erasable read only memory (PEROM). The device is manufactured using Atmel‟s high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C51 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications. Function characteristicThe AT89C51 provides the following standard features: 4K bytes of Flash, 128 bytes of RAM, 32 I/O lines, two 16-bit timer/counters, a five vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator and clock circuitry. In addition, the AT89C51 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. The Power-down Mode saves the RAM contents but freezes the oscillator disabling all other chip functions until the next hardware reset.Pin DescriptionVCC:Supply voltage.GND:Ground.Port 0:Port 0 is an 8-bit open-drain bi-directional I/O port. As an output port, each pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as highimpedance inputs.Port 0 may also be configured to be the multiplexed loworder address/data bus during accesses to external program and data memory. In this mode P0 has internal pullups.Port 0 also receives the code bytes during Flash programming,and outputs the code bytes during programverification. External pullups are required during programverification.Port 1Port 1 is an 8-bit bi-directional I/O port with internal pullups.The Port 1 output buffers can sink/source four TTL inputs.When 1s are written to Port 1 pins they are pulled high by the internal pullups and can be used as inputs. As inputs,Port 1 pins that are externally being pulled low will source current (IIL) because of the internal pullups.Port 1 also receives the low-order address bytes during Flash programming and verification.Port 2Port 2 is an 8-bit bi-directional I/O port with internal pullups.The Port 2 output buffers can sink/source four TTL inputs.When 1s are written to Port 2 pins they are pulled high by the internal pullups and can be used as inputs. As inputs,Port 2 pins that are externally being pulled low will source current, because of the internal pullups.Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16-bit addresses. In this application, it uses strong internal pullupswhen emitting 1s. During accesses to external data memory that use 8-bit addresses, Port 2 emits the contents of the P2 Special Function Register.Port 2 also receives the high-order address bits and some control signals during Flash programming and verification.Port 3Port 3 is an 8-bit bi-directional I/O port with internal pullups.The Port 3 output buffers can sink/source four TTL inputs.When 1s are written to Port 3 pins they are pulled high by the internal pullups and can be used as inputs. As inputs,Port 3 pins that are externally being pulled low will source current (IIL) because of the pullups.Port 3 also serves the functionsof various special features of the AT89C51 as listed below:Port 3 also receives some control signals for Flash programming and verification.RSTReset input. A high on this pin for two machine cycles while the oscillator is running resets the device.ALE/PROGAddress Latch Enable output pulse for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input (PROG) during Flash programming.In normal operation ALE is emitted at a constant rate of 1/6 the oscillator frequency, and may be used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to external Data Memory.If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if the microcontroller is in external execution mode.PSENProgram Store Enable is the read strobe to external program memory.When the AT89C51 is executing code from external program memory, PSEN is activated twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory.EA/VPPExternal Access Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset.EA should be strapped to VCC for internal program executions.This pin also receives the 12-volt programming enable voltage(VPP) during Flash programming, for parts that require12-volt VPP.XTAL1Input to the inverting oscillator amplifier and input to the internal clock operating circuit. XTAL2Output from the inverting oscillator amplifier.Oscillator CharacteristicsXTAL1 and XTAL2 are the input and output, respectively,of an inverting amplifier which can be configured for use as an on-chip oscillator, as shown in Figure 1.Either a quartz crystal or ceramic resonator may be used. To drive the device from an external clock source, XTAL2 should be left unconnected while XTAL1 is driven as shown in Figure 2.There are no requirements on the duty cycle of the external clock signal, since the input to the internal clocking circuitry is through a divide-by-two flip-flop, but minimum and maximum voltage high and low time specifications must be observed.中文翻译:微型计算机控制系统(单片机控制系统)广义地说,微型计算机控制系统(单片机控制系统)是用于处理信息的,这种被用于处理的信息可以是电话交谈,也可以是仪器的读数或者是一个企业的帐户,但是各种情况下都涉及到相同的主要操作:信息的处理、信息的存储和信息的传递。
电子信息工程专业毕设 文献翻译 附英文原文
5.3. 时钟独立的显性误差
对于每一个特定的GPS时钟,在每个适用的时间从KF1相位偏差估计值减去 UECC估计值, 去估计其OEIC的相位。 在测量加工, OEIC包含在几部分纳秒内(见 图4)。图4展示了的两种情况下地面工作站时钟S1的OEIC。在蓝线的可见区间和 KF1测距处理显然有别于没有测量的传播间隔。在测量处理期间,KF1估计误差 的观察目标部分包含在几部分纳秒内。OEIC的协方差顺序计算需要每个时间点 的 KF1相位偏差估计误差和UECC估计误差的互协方差矩阵值。 我尚未能计算这
X K 1|K 1 X K 1|K K K 1[ y K 1 y( X K 1|K )]
Hale Waihona Puke (5)5. 难以观察的 GPS 时钟系统
GPS时间是由作战空军(USAF)卡尔曼滤波器处理 GPS伪距测量产生的。 GPS时间是多个GPS时钟的平均相位, 可是, 通过 GPS伪距测量, 每个运行的GPS 时钟的时钟相位是难以观察的,演示如下。GPS导航星的轨道参数是从GPS伪距 观测可观察到的。从GPS伪距测量可以得到USAF(美国空军)卡尔曼滤波器估 计轨道参数和时钟同步参数, 因此以这种方式将状态估计值分为隐式的时钟参数 子集和显式的轨道参数子集。通过应用谢尔曼有关MU函数的定理,演示了这种 分区方式。
4.3.2. 非线性函数 MU
计算 n ×1 矩阵滤波器增益 K K 1 :
T T 1 K K 1 PK 1|K H K 1 [ H K 1 PK 1| K H K 1 R K 1 ]
(4)
滤波器测量更新 n×1 状态估计矩阵 X K 1|K 1 ,观测 yK+1 得
态估计误差协方差方阵(正特征值)
关于电子信息工程的英语作文
关于电子信息工程的英语作文英文回答:Electronic Information Engineering (EIE) is adiscipline that integrates electronics, information, and communication technologies to design, develop, and analyze electronic systems. It encompasses a wide range of subfields, including:Electronics: The study of electronic circuits, devices, and systems.Information Technology (IT): The use of computers, networks, and software to store, process, and transmit data.Communications: The transmission of information over long distances using various technologies such as radio, microwave, and fiber optics.Signal Processing: The manipulation of electricalsignals to extract useful information or improve their quality.EIE plays a crucial role in modern society, enabling advancements in fields such as telecommunications, healthcare, transportation, and industrial automation.中文回答:电子信息工程。
电子信息工程专业外文翻译----一个高效率的CMOS超宽带信号产生模块
毕业设计(论文)外文翻译资料翻译资料名称(外文) A Power-Efficient CMOS UWBSignal-Generation Module翻译资料名称(中文)一个高效率的CMOS超宽带信号产生模块电子信息工程院(系)电子信息工程专业学号B06093011学生姓名指导教师起讫日期2009. 2. 23 ~ 2009. 6. 4设计地点中文译文一个高效率的CMOS超宽带信号产生模块摘要这篇论文提出了一个新的载波超宽带发射机结构,同时给出了它的CMOS实现结构。
这新的发射机拓扑结构采用一个两级开关。
它增强了射频功率效率,降低了直流功率的损耗和电路的复杂性。
发射机使用0.18μm CMOS工艺实现,超宽带信号生成模块包括一个超宽带SPST开关和一个可调脉冲发生器。
测量结果表明,产生10dB可变的超宽带信号,其信号带宽从0.5GHz变化到4GHz,并且调谐中心频率覆盖了整个超宽带频率,即从3.1GHz到10.6GHz。
CMOS模块直流功耗小于2mW。
本文中提出的载波超宽带发射机和论证的模块提供了一个对超宽带信号产生有吸引力的方法,同时他们可以应用于超宽带通信和雷达。
1、引言超宽带技术获得重大的利益,尤其是在1998年的FCC的调查公告和在2002年在3.1-10.6GHz频段中无牌使用超宽带设备的调查与整治。
超宽带技术是有前途的技术,它的能力包括准确的定位和高效短距离点对点网络以及高分辨率遥感。
载波超宽带信号已广泛应用于各种雷达和通信系统中。
通过天线它们拥有更加方便的频谱管理和减少失真的优势。
在典型的超宽带发射机中,生成载波的超宽带电压信号必须被发射到一个宽带功率放大器,从而获得达到所需的功率水平。
这个方法有两个重要的缺点:第一,超宽带功率放大器的设计挑战;第二,在低脉冲重复频率中的低功率效率。
在本文中,提出了一种新的载波超宽带发射机结构。
它不仅仅提高了功率效率,而且减少电路的复杂性。
同时文章论证了新的CMOS发射机模块性能可操作性和性能,频率覆盖了整个3.1GHz到10.6GHz的超宽带频带和可变带宽500MHz到4GHz。
外文翻译--定时器运行
毕业设计(论文)外文资料翻译学院(系):电子电气工程学院专业:电子信息工程姓名:学号:外文出处: The 8051 Microcontroller附件: 1.外文资料翻译译文;2.外文原文。
附件1:外文资料翻译译文第四章 定时器运行4.1定时器介绍在本章中,我们研究了8051的片上定时器。
我们开始简化视图,因为它们通常用于微处理器或微控制器的计时器。
一个系列的定时器被划分为两个触发器,触发器的接收输入信号作为时钟源。
时钟频率除以2的时钟被应用于第一个触发器。
第一个触发器的输出时钟为第二个触发器除以2等。
由于每个连续的阶段都除以2,N 个分期定时器的输入时钟频率也除以2。
最后一个阶段的输出时钟触发器,定时器溢出或者标记都是由软件测试或产生中断。
从定时器启动后,定时触发器的二进制值可以被看作是一个“数量”的时钟脉冲(或“事件”)。
一个16位定时器,例如,将数从0000H 到FFFFH 。
溢出标志设置的计数值为FFFFH-0000H 溢出。
一个简单计时器的操作是在3位定时器上的,每个阶段是作为一个类型的三维负边沿触发触发器2分频模式(即经营所示的输出连接到D 输入)。
触发器的标志仅仅是一个类型D 锁存器,被置于计时器的最后阶段。
它在时序图是显而易见,第一阶段是0Q 1 / 2的时钟频率,第二阶段是时钟频率的1 / 4。
十进制计数显示,并且很容易通过检查核实三个触发器是否过时。
例如,数“4”发生时,1Q = 1。
2Q =0,3Q = 0(104=2100)。
定时器是以几乎所有的控制为导向的应用,8051定时器也不例外。
两个16位的定时器有四种操作模式。
第三个16位定时器的三种操作模式是增加8052。
定时器用于(a )时间间隔定时,(b )事件计数,(c )内置串行端口的波特率速率生成。
每一个定时器都是一个16位的定时器,因此162= 65536除以16就是最后阶段的输入时钟频率。
在间隔定时应用时,编程定时器溢出;在定期的时间间隔是就要设置定时器溢出标志。
毕业设计英文 翻译(原文)
编号:毕业设计(论文)外文翻译(原文)院(系):桂林电子科技大学专业:电子信息工程学生姓名: xx学号: xxxxxxxxxxxxx 指导教师单位:桂林电子科技大学姓名: xxxx职称: xx2014年x月xx日Timing on and off power supplyusesThe switching power supply products are widely used in industrial automation and control, military equipment, scientific equipment, LED lighting, industrial equipment,communications equipment,electrical equipment,instrumentation, medical equipment, semiconductor cooling and heating, air purifiers, electronic refrigerator, LCD monitor, LED lighting, communications equipment, audio-visual products, security, computer chassis, digital products and equipment and other fields.IntroductionWith the rapid development of power electronics technology, power electronics equipment and people's work, the relationship of life become increasingly close, and electronic equipment without reliable power, into the 1980s, computer power and the full realization of the switching power supply, the first to complete the computer Power new generation to enter the switching power supply in the 1990s have entered into a variety of electronic, electrical devices, program-controlled switchboards, communications, electronic testing equipment power control equipment, power supply, etc. have been widely used in switching power supply, but also to promote the rapid development of the switching power supply technology .Switching power supply is the use of modern power electronics technology to control the ratio of the switching transistor to turn on and off to maintain a stable output voltage power supply, switching power supply is generally controlled by pulse width modulation (PWM) ICs and switching devices (MOSFET, BJT) composition. Switching power supply and linear power compared to both the cost and growth with the increase of output power, but the two different growth rates. A power point, linear power supply costs, but higher than the switching power supply. With the development of power electronics technology and innovation, making the switching power supply technology to continue to innovate, the turning points of this cost is increasingly move to the low output power side, the switching power supply provides a broad space for development.The direction of its development is the high-frequency switching power supply, high frequency switching power supply miniaturization, and switching power supply into a wider range of application areas, especially in high-tech fields, and promote the miniaturization of high-tech products, light of. In addition, the development and application of the switching power supply in terms of energy conservation, resource conservation and environmental protection are of great significance.classificationModern switching power supply, there are two: one is the DC switching power supply; the other is the AC switching power supply. Introduces only DC switching power supply and its function is poor power quality of the original eco-power (coarse) - such as mains power or battery power, converted to meet the equipment requirements of high-quality DC voltage (Varitronix) . The core of the DC switching power supply DC / DC converter. DC switching power supply classification is dependent on the classification of DC / DC converter. In other words, the classification of the classification of the DC switching power supply and DC/DC converter is the classification of essentially the same, the DC / DC converter is basically a classification of the DC switching power supply.DC /DC converter between the input and output electrical isolation can be divided into two categories: one is isolated called isolated DC/DC converter; the other is not isolated as non-isolated DC / DC converter.Isolated DC / DC converter can also be classified by the number of active power devices. The single tube of DC / DC converter Forward (Forward), Feedback (Feedback) two. The double-barreled double-barreled DC/ DC converter Forward (Double Transistor Forward Converter), twin-tube feedback (Double Transistor Feedback Converter), Push-Pull (Push the Pull Converter) and half-bridge (Half-Bridge Converter) four. Four DC / DC converter is the full-bridge DC / DC converter (Full-Bridge Converter).Non-isolated DC / DC converter, according to the number of active power devices can be divided into single-tube, double pipe, and four three categories. Single tube to a total of six of the DC / DC converter, step-down (Buck) DC / DC converter, step-up (Boost) DC / DC converters, DC / DC converter, boost buck (Buck Boost) device of Cuk the DC / DC converter, the Zeta DC / DC converter and SEPIC, the DC / DC converter. DC / DC converters, the Buck and Boost type DC / DC converter is the basic buck-boost of Cuk, Zeta, SEPIC, type DC / DC converter is derived from a single tube in this six. The twin-tube cascaded double-barreled boost (buck-boost) DC / DC converter DC / DC converter. Four DC / DC converter is used, the full-bridge DC / DC converter (Full-Bridge Converter).Isolated DC / DC converter input and output electrical isolation is usually transformer to achieve the function of the transformer has a transformer, so conducive to the expansion of the converter output range of applications, but also easy to achieve different voltage output , or a variety of the same voltage output.Power switch voltage and current rating, the converter's output power is usually proportional to the number of switch. The more the number of switch, the greater the output power of the DC / DC converter, four type than the two output power is twice as large,single-tube output power of only four 1/4.A combination of non-isolated converters and isolated converters can be a single converter does not have their own characteristics. Energy transmission points, one-way transmission and two-way transmission of two DC / DC converter. DC / DC converter with bi-directional transmission function, either side of the transmission power from the power of lateral load power from the load-lateral side of the transmission power.DC / DC converter can be divided into self-excited and separately controlled. With the positive feedback signal converter to switch to self-sustaining periodic switching converter, called self-excited converter, such as the the Luo Yeer (Royer,) converter is a typical push-pull self-oscillating converter. Controlled DC / DC converter switching device control signal is generated by specialized external control circuit.the switching power supply.People in the field of switching power supply technology side of the development of power electronic devices, while the development of the switching inverter technology, the two promote each other to promote the switching power supply annual growth rate of more than two digits toward the light, small, thin, low-noise, high reliability, the direction of development of anti-jamming. Switching power supply can be divided into AC / DC and DC / DC two categories, AC / AC DC / AC, such as inverters, DC / DC converter is now modular design technology and production processes at home and abroad have already matured and standardization, and has been recognized by the user, but AC / DC modular, its own characteristics make the modular process, encounter more complex technology and manufacturing process. Hereinafter to illustrate the structure and characteristics of the two types of switching power supply.Self-excited: no external signal source can be self-oscillation, completely self-excited to see it as feedback oscillation circuit of a transformer.Separate excitation: entirely dependent on external sustain oscillations, excited used widely in practical applications. According to the excitation signal structure classification; can be divided into pulse-width-modulated and pulse amplitude modulated two pulse width modulated control the width of the signal is frequency, pulse amplitude modulation control signal amplitude between the same effect are the oscillation frequency to maintain within a certain range to achieve the effect of voltage stability. The winding of the transformer can generally be divided into three types, one group is involved in the oscillation of the primary winding, a group of sustained oscillations in the feedback winding, there is a group of load winding. Such as Shanghai is used in household appliances art technological production of switching power supply, 220V AC bridge rectifier, changing to about 300V DC filter added tothe collector of the switch into the transformer for high frequency oscillation, the feedback winding feedback to the base to maintain the circuit oscillating load winding induction signal, the DC voltage by the rectifier, filter, regulator to provide power to the load. Load winding to provide power at the same time, take up the ability to voltage stability, the principle is the voltage output circuit connected to a voltage sampling device to monitor the output voltage changes, and timely feedback to the oscillator circuit to adjust the oscillation frequency, so as to achieve stable voltage purposes, in order to avoid the interference of the circuit, the feedback voltage back to the oscillator circuit with optocoupler isolation.technology developmentsThe high-frequency switching power supply is the direction of its development, high-frequency switching power supply miniaturization, and switching power supply into the broader field of application, especially in high-tech fields, and promote the development and advancement of the switching power supply, an annual more than two-digit growth rate toward the light, small, thin, low noise, high reliability, the direction of the anti-jamming. Switching power supply can be divided into AC / DC and DC / DC two categories, the DC / DC converter is now modular design technology and production processes at home and abroad have already matured and standardized, and has been recognized by the user, but modular AC / DC, because of its own characteristics makes the modular process, encounter more complex technology and manufacturing process. In addition, the development and application of the switching power supply in terms of energy conservation, resource conservation and environmental protection are of great significance.The switching power supply applications in power electronic devices as diodes, IGBT and MOSFET.SCR switching power supply input rectifier circuit and soft start circuit, a small amount of applications, the GTR drive difficult, low switching frequency, gradually replace the IGBT and MOSFET.Direction of development of the switching power supply is a high-frequency, high reliability, low power, low noise, jamming and modular. Small, thin, and the key technology is the high frequency switching power supply light, so foreign major switching power supply manufacturers have committed to synchronize the development of new intelligent components, in particular, is to improve the secondary rectifier loss, and the power of iron Oxygen materials to increase scientific and technological innovation in order to improve the magnetic properties of high frequency and large magnetic flux density (Bs), and capacitor miniaturization is a key technology. SMT technology allows the switching power supply has made considerable progress, the arrangement of the components in the circuit board on bothsides, to ensure that the light of the switching power supply, a small, thin. High-frequency switching power supply is bound to the traditional PWM switching technology innovation, realization of ZVS, ZCS soft-switching technology has become the mainstream technology of the switching power supply, and a substantial increase in the efficiency of the switching power supply. Indicators for high reliability, switching power supply manufacturers in the United States by reducing the operating current, reducing the junction temperature and other measures to reduce the stress of the device, greatly improve the reliability of products.Modularity is the overall trend of switching power supply, distributed power systems can be composed of modular power supply, can be designed to N +1 redundant power system, and the parallel capacity expansion. For this shortcoming of the switching power supply running noise, separate the pursuit of high frequency noise will also increase, while the use of part of the resonant converter circuit technology to achieve high frequency, in theory, but also reduce noise, but some The practical application of the resonant converter technology, there are still technical problems, it is still a lot of work in this field, so that the technology to be practical.Power electronics technology innovation, switching power supply industry has broad prospects for development. To accelerate the pace of development of the switching power supply industry in China, it must take the road of technological innovation, out of joint production and research development path with Chinese characteristics and contribute to the rapid development of China's national economy.Developments and trends of the switching power supply1955 U.S. Royer (Roger) invented the self-oscillating push-pull transistor single-transformer DC-DC converter is the beginning of the high-frequency conversion control circuit 1957 check race Jen, Sen, invented a self-oscillating push-pull dual transformers, 1964, U.S. scientists canceled frequency transformer in series the idea of switching power supply, the power supply to the size and weight of the decline in a fundamental way. 1969 increased due to the pressure of the high-power silicon transistor, diode reverse recovery time shortened and other components to improve, and finally made a 25-kHz switching power supply.At present, the switching power supply to the small, lightweight and high efficiency characteristics are widely used in a variety of computer-oriented terminal equipment, communications equipment, etc. Almost all electronic equipment is indispensable for a rapid development of today's electronic information industry power mode. Bipolar transistor made of 100kHz, 500kHz power MOS-FET made, though already the practical switching power supply is currently available on the market, but its frequency to be further improved. Toimprove the switching frequency, it is necessary to reduce the switching losses, and to reduce the switching losses, the need for high-speed switch components. However, the switching speed will be affected by the distribution of the charge stored in the inductance and capacitance, or diode circuit to produce a surge or noise. This will not only affect the surrounding electronic equipment, but also greatly reduce the reliability of the power supply itself. Which, in order to prevent the switching Kai - closed the voltage surge, RC or LC buffers can be used, and the current surge can be caused by the diode stored charge of amorphous and other core made of magnetic buffer . However, the high frequency more than 1MHz, the resonant circuit to make the switch on the voltage or current through the switch was a sine wave, which can reduce switching losses, but also to control the occurrence of surges. This switch is called the resonant switch. Of this switching power supply is active, you can, in theory, because in this way do not need to greatly improve the switching speed of the switching losses reduced to zero, and the noise is expected to become one of the high-frequency switching power supply The main ways. At present, many countries in the world are committed to several trillion Hz converter utility.the principle of IntroductionThe switching power supply of the process is quite easy to understand, linear power supplies, power transistors operating in the linear mode and linear power, the PWM switching power supply to the power transistor turns on and off state, in both states, on the power transistor V - security product is very small (conduction, low voltage, large current; shutdown, voltage, current) V oltammetric product / power device is power semiconductor devices on the loss.Compared with the linear power supply, the PWM switching power supply more efficient process is achieved by "chopping", that is cut into the amplitude of the input DC voltage equal to the input voltage amplitude of the pulse voltage. The pulse duty cycle is adjusted by the switching power supply controller. Once the input voltage is cut into the AC square wave, its amplitude through the transformer to raise or lower. Number of groups of output voltage can be increased by increasing the number of primary and secondary windings of the transformer. After the last AC waveform after the rectifier filter the DC output voltage.The main purpose of the controller is to maintain the stability of the output voltage, the course of their work is very similar to the linear form of the controller. That is the function blocks of the controller, the voltage reference and error amplifier can be designed the same as the linear regulator. Their difference lies in the error amplifier output (error voltage) in the drive before the power tube to go through a voltage / pulse-width conversion unit.Switching power supply There are two main ways of working: Forward transformand boost transformation. Although they are all part of the layout difference is small, but the course of their work vary greatly, have advantages in specific applications.the circuit schematicThe so-called switching power supply, as the name implies, is a door, a door power through a closed power to stop by, then what is the door, the switching power supply using SCR, some switch, these two component performance is similar, are relying on the base switch control pole (SCR), coupled with the pulse signal to complete the on and off, the pulse signal is half attentive to control the pole voltage increases, the switch or transistor conduction, the filter output voltage of 300V, 220V rectifier conduction, transmitted through the switching transformer secondary through the transformer to the voltage increase or decrease for each circuit work. Oscillation pulse of negative semi-attentive to the power regulator, base, or SCR control voltage lower than the original set voltage power regulator cut-off, 300V power is off, switch the transformer secondary no voltage, then each circuit The required operating voltage, depends on this secondary road rectifier filter capacitor discharge to maintain. Repeat the process until the next pulse cycle is a half weeks when the signal arrival. This switch transformer is called the high-frequency transformer, because the operating frequency is higher than the 50HZ low frequency. Then promote the pulse of the switch or SCR, which requires the oscillator circuit, we know, the transistor has a characteristic, is the base-emitter voltage is 0.65-0.7V is the zoom state, 0.7V These are the saturated hydraulic conductivity state-0.1V-0.3V in the oscillatory state, then the operating point after a good tune, to rely on the deep negative feedback to generate a negative pressure, so that the oscillating tube onset, the frequency of the oscillating tube capacitor charging and discharging of the length of time from the base to determine the oscillation frequency of the output pulse amplitude, and vice versa on the small, which determines the size of the output voltage of the power regulator. Transformer secondary output voltage regulator, usually switching transformer, single around a set of coils, the voltage at its upper end, as the reference voltage after the rectifier filter, then through the optocoupler, this benchmark voltage return to the base of the oscillating tube pole to adjust the level of the oscillation frequency, if the transformer secondary voltage is increased, the sampling coil output voltage increases, the positive feedback voltage obtained through the optocoupler is also increased, this voltage is applied oscillating tube base, so that oscillation frequency is reduced, played a stable secondary output voltage stability, too small do not have to go into detail, nor it is necessary to understand the fine, such a high-power voltage transformer by switching transmission, separated and after the class returned by sampling the voltage from the opto-coupler pass separated after class, so before the mains voltage, and after the classseparation, which is called cold plate, it is safe, transformers before power is independent, which is called switching power supply.the DC / DC conversionDC / DC converter is a fixed DC voltage transformation into a variable DC voltage, also known as the DC chopper. There are two ways of working chopper, one Ts constant pulse width modulation mode, change the ton (General), the second is the frequency modulation, the same ton to change the Ts, (easy to produce interference). Circuit by the following categories:Buck circuit - the step-down chopper, the average output voltage U0 is less than the input voltage Ui, the same polarity.Boost Circuit - step-up chopper, the average output voltage switching power supply schematic U0 is greater than the input voltage Ui, the same polarity.Buck-Boost circuit - buck or boost chopper, the output average voltage U0 is greater than or less than the input voltage Ui, the opposite polarity, the inductance transmission.Cuk circuit - a buck or boost chopper, the output average voltage U0 is greater than or less than the input voltage Ui, the opposite polarity, capacitance transmission.The above-mentioned non-isolated circuit, the isolation circuit forward circuits, feedback circuit, the half-bridge circuit, the full bridge circuit, push-pull circuit. Today's soft-switching technology makes a qualitative leap in the DC / DC the U.S. VICOR company design and manufacture a variety of ECI soft-switching DC / DC converter, the maximum output power 300W, 600W, 800W, etc., the corresponding power density (6.2 , 10,17) W/cm3 efficiency (80-90)%. A the Japanese Nemic Lambda latest using soft-switching technology, high frequency switching power supply module RM Series, its switching frequency (200 to 300) kHz, power density has reached 27W/cm3 with synchronous rectifier (MOSFETs instead of Schottky diodes ), so that the whole circuit efficiency by up to 90%.AC / DC conversionAC / DC conversion will transform AC to DC, the power flow can be bi-directional power flow by the power flow to load known as the "rectification", referred to as "active inverter power flow returned by the load power. AC / DC converter input 50/60Hz AC due must be rectified, filtered, so the volume is relatively large filter capacitor is essential, while experiencing safety standards (such as UL, CCEE, etc.) and EMC Directive restrictions (such as IEC, FCC, CSA) in the AC input side must be added to the EMC filter and use meets the safety standards of the components, thus limiting the miniaturization of the volume of AC / DC power, In addition, due to internal frequency, high voltage, current switching, making the problem difficult to solve EMC also high demands on the internal high-density mountingcircuit design, for the same reason, the high voltage, high current switch makes power supply loss increases, limiting the AC / DC converter modular process, and therefore must be used to power system optimal design method to make it work efficiency to reach a certain level of satisfaction.AC / DC conversion circuit wiring can be divided into half-wave circuit, full-wave circuit. Press the power phase can be divided into single-phase three-phase, multiphase. Can be divided into a quadrant, two quadrant, three quadrants, four-quadrant circuit work quadrant.he selection of the switching power supplySwitching power supply input on the anti-jamming performance, compared to its circuit structure characteristics (multi-level series), the input disturbances, such as surge voltage is difficult to pass on the stability of the output voltage of the technical indicators and linear power have greater advantages, the output voltage stability up to (0.5)%. Switching power supply module as an integrated power electronic devices should be selected。
电子信息工程英语求职信
电子信息工程英语求职信Dear Hiring Manager,I am writing to express my interest in the electronic engineering position at your esteemed company. With a Bachelor's degree in Electronic Information Engineering from XYZ University, I am confident in my ability to contribute positively to your team and help drive innovation in the field.During my time at university, I developed a strong foundation in electronic engineering principles and gained practical experience through projects and internships. I have a solid understanding of circuit design, programming, communication systems, and signal processing. I have also developed strong analytical and problem-solving skills, which have enabled me to tackle complex engineering challenges effectively.I am particularly interested in the intersection of electronics and information technology, and how advancements in these areas can be leveraged to create smarter and more efficient systems. I am keen to apply my knowledge and skills to develop cutting-edge solutions that can have a real-world impact.In addition to my technical skills, I also possess excellent communication and teamwork abilities. I have worked on multidisciplinary projects that required collaboration with team members from diverse backgrounds. I am a quick learner and adapt easily to new environments, making me a valuable asset to any team.I am highly motivated and passionate about electronic engineering, and I am excited about the opportunity to contribute to your company's mission and goals. I believe that my skills and experience make me a strong candidate for this position, and I am eager to bring my expertise to your team.Thank you for considering my application. I look forward to the possibility of discussing my qualifications further. Please feel free to contact me at your convenience to schedule an interview.Sincerely,[Your Name]。
外文资料翻译
毕业设计(论文)外文资料翻译题目: 数字滤波器的仿真与实现院系名称:信息科学与工程学院专业班级:电子信息工程11级4班学生姓名:吴亚辉学号: 201116910421 指导教师:靳婷教师职称:讲师附件: 1.外文资料翻译译文;2.外文原文。
指导教师评语:签名:2015年3月30日附件1:外文资料翻译译文数字滤波器的仿真与实现——摘自《International Broadcasting Convention 2003》第488页~第499页A. Dueñas1, J. C. Pujol2, A. Martín2, C. Peláez2, F. Díaz2, G. Gomez1,F. Martin11PRODYS, Spain; 2Universidad CIII de Madrid, Spain 随着信息时代和数字世界的到来,数字信号处理已成为当今一门极其重要的学科和技术领域。
数字信号处理在通信、语音、图像、自动控制、雷达、军事、航空航天、医疗和家用电器等众多领域得到了广泛的应用。
在数字信号处理应用中,数字滤波器十分重要并已获得广泛应用。
1、数字滤波器介绍:模拟和数字滤波器在信号处理、过滤功能是一个不排除部分信息,如随机噪音、提取有用的信号部分,如部分地势在一定的频率范围.以下方框图说明基本思路.有两大类型的过滤, 模拟以及数字 . 他们是完全不同的物理结构,如何工作. 类比电子电路模拟用的过滤部分组成,例如由电阻、电容、放大器和生产所需的过滤效果. 这种过滤器被广泛使用的电路减少噪音等方面的应用,提高视频信号、图像均衡的高科技传真系统等众多领域. 有完善的技术标准设计的模拟电路进行过滤特定要求. 在各个阶段,是一个信号,是电机电压和过滤,目前直接的物理模拟量(例如声音或视频信号和变频器生产)处理. 数码过滤用数字进行数值计算处理器的信号抽样值. 处理器的可能通用计算机等PC或专业发展计划图(数字信号处理器)芯片. 模拟信号必须先投入使用的取样和数码艺术发展局(模拟到数字转换器). 由此二元多,占抽样连续输入信号的价值,转移到处理器,进行数字计算. 这些计算通常涉及多方面的投入和增加产品价值的共同因素. 如有必要,这些计算结果,现在是抽样信号值的过滤,产出通过发展援助委员会(类比数位转换器来)信号转换回模拟形式.看到一个数字过滤,信号是由一系列数字,而不是电压或逆流.以下图表显示了这种制度的基本格局:滤波器是指用来对输入信号进行滤波的硬件或软件。
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西安邮电大学毕业设计(论文) 外文文献及翻译学院:电子工程学院系部:电子信息工程专业:电子信息工程班级:电子1003班学生姓名:郭欢导师姓名:张新职称:教授起止时间:2014年3月10日——2014年6月15日Cloud computing — The business perspectiveAbstractThe evolution of cloud computing over the past few years is potentially one of the major advances in the history of computing. However, if cloud computing is to achieve its potential, there needs to be a clear understanding of the various issues involved, both from the perspectives of the providers and the consumers of the technology. While a lot of research is currently taking place in the technology itself, there is an equally urgent need for understanding the business-related issues surrounding cloud computing. In this article, we identify the strengths, weaknesses, opportunities and threats for the cloud computing industry. We then identify the various issues that will affect the different stakeholders of cloud computing. We also issue a set of recommendations for the practitioners who will provide and manage this technology. For IS researchers, we outline the different areas of research that need attention so that we are in a position to advice the industry in the years to come. Finally, we outline some of the key issues facing governmental agencies who, due to the unique nature of the technology, will have to become intimately involved in the regulation of cloud computing.1.IntroductionThe emergence of the phenomenon commonly known as cloud computing represents a fundamental change in the way information technology (IT) services are invented, developed, deployed, scaled, updated, maintained and paid for. Computing as we know today reflects a paradox —on one hand, computers continue to become exponentially more powerful and the per-unit cost of computing continues to fall rapidly, so much so that computing power per se is nowadays considered to be largely a commodity. On the other hand, as computing becomes more pervasive within the organization, the increasing complexity of managing the whole infrastructure of disparate information architectures and distributed data and software has made computing more expensive than ever before to an organization. The promise of cloud computing is to deliver all the functionality of existing information technology services (and in fact enable new functionalities that are hitherto infeasible) even as it dramatically reduces the upfront costs of computing that deter many organizations from deploying many cutting-edge IT services. All such promise has led to lofty expectations —Gartner Research expects cloud computing to be a$150 billionbusiness by 2014, and according to AMI partners, small and medium businesses are expected to spend over $100 billion on cloud computing by 2014.The impetus for change right now is seen predominantly from a costs perspective (even though, as we discuss later in the document, the promises from a technological functionality perspective are equally attractive), as organizations increasingly discover that their substantial capital investments in information technology are often grossly underutilized. One recent survey of six corporate data centers found that most of the servers were using just 10–30% of their available computing power, while desktop computers have an average capacity utilization of less than 5% .. Equally pertinent are the maintenance and service costs that have proved to be a drain on scarce corporate resources. A recently conducted survey by Gartner Research indicated that about two-thirds of the average corporate IT staffing budget goes towards routine support and maintenance activities, which does seem anachronistic in an age of globalized and cutthroat competition —as the CEO of a cloud platform provider commented recently, “If you woke up this morning and read in The Wall Street Journal that, say, has stopped using UPS and FedEx and the U.S. mail, and had bought fleets of trucks and started leasing airport hubs and delivering products themselves, you would say they were out of their minds. Why is that much more insane than a health care company spending $2 billion a year on information technology?”.Cloud computing represents a convergence of two major trends in information technology —(a) IT efficiency, whereby the power of modern computers is utilized more efficiently through highly scalable hardware and software resources and (b) business agility, whereby IT can be used as a competitive tool through rapid deployment, parallel batch processing, use of compute-intensive business analytics and mobile interactive applications that respond in real time to user requirements. The concept of IT efficiency also embraces the ideas encapsulated in green computing, since not only are the computing resources used more efficiently, but further, the computers can be physically located in geographical areas that have access to cheap electricity while their computing power can be accessed long distances away over the Internet. However, as the term business agility implies, cloud computing is not just about cheap computing —it is also about businesses being able to use computational tools that can be deployed and scaled rapidly, even as it reduces the need for huge upfront investments that characterize enterprise IT setups today.。