翻譯是在準確（信）、通順（達）、優美（雅）的基礎上，把一種語言信息轉變成另一種語言信息的行為。翻譯是將一種相對陌生的表達方式，轉換成相對熟悉的表達方式的過程。其內容有語言、文字、圖形、符號和視頻翻譯。其中，在甲語和乙語中，“翻”是指的這兩種語， 以下是為大家整理的關于情書英文翻譯3篇 , 供大家參考選擇。
情書英文翻譯3篇
第1篇: 情書英文翻譯
中英文對照翻譯
Transducer in the water control system applications -PLC
Currently, the water level control in a large part of the electrical pumps are not towing gear shift system, no gear shift most of the electrical energy consumed in the water supply to the frequent changes in the pumps stopped. This not only makes the electrical work in inefficient zones, cut short the useful life of electrical and electrical equipment for the frequent failure to stop the high rate, leading to serious waste of water resources, system maintenance, repairs larger workload.
With high living water and industrial water gradually increased, the traditional control methods that are outdated. Originally used for artificial water level control, water level due to the lack of accurate positioning hour monitoring, it is difficult to accurately control the pumps have stopped; Using buoys or mechanical control devices such as water supply situation has made some changes, but because of mechanical failure more devices, poor reliability to maintenance will face great trouble.
Frequency conversion technology, with its superiority in the area of energy efficiency and Hengya pressure control system can be solved by the existence of the above problems. Consider selecting Chanpianji or Plc and transducer combination at the core of the system can achieve a better control results. But in software design, Plc programming of more than Shanpianji concise, and visual; From the hardware interface considerations, Shanpianji circuit slightly complex; From the economic considerations, the Plc processes are mature, cost and small Plc Shanpianji a little, because the system parameters to be adjusted in accordance with the situation on the ground, Plc software, the time parameters adjustments simpler, so more conducive to after-sale personnel. For the above reasons, the selection of the Omron Plc CPM1 series with the transducer as ABB control core, coupled with PSW7 conditioners and WSP300 Biansongqi pressure, the effect was very good control, software design simple hardware interface simple and feasible, reliable, the entire system Xingjiebi very high.
Transducer in the water system in conjunction with the introduction of small Plc technology not only change the traditional use of water control valves, and in energy conservation, Hengya control, are very good results, the paper introduced a transducer --PLC control technology in the pump control applications.
Control system using one Taiwan transducer can bring three pumps, pumps can work at the frequency pump in the conventional model can work in the frequency conversion pump model. At the pump only in frequency conversion or one of the working frequency mode through two relays efficient ensure its security and reliability. System structure as figure 1 shows, the use of placement in the life of water pressure Biansongqi water pressure signal transmission to the regulator, in accordance with the regulator to set the value and warning of lower compared to send signals to the Plc and the transducer, the system has stopped pumping from regulator pressure level signals and transducer frequency range signal, if the low pressure, regulator to the Plc a pressure lower signal Plc activation transducer, and a frequency conversion 1st pumps work state, and the output frequency gradually increasing, after a period of adjustment, such as pressure is low, then, Plc for 1st pumps in the frequency of work, 2nd pump frequency conversion work at the state pumps, such as pressure is low, 2 pumps at the frequency for the state and make the state 3rd pumps in frequency conversion work, and so on. When the pressure regulator to limit the police on duty, regulator output reduction, transducer frequency reduced to the low frequency range set value at a given frequency transducer signals to the lower PLC,PLC According to Kai principle pause control pump operation sequence, for example, Plc received lower frequency signals, the system pumps state is the frequency 1st, 2nd-frequency, 3rd frequency conversion, the first time 1st pumps activated, the first stop, then as the pressure was high, then stopped on the 2nd pumps. Each system is used for slow start, high-speed operation in order to enhance operational efficiency.
Introduces the frequency changer union small PLC technology in the water supply system, not only change tradition with valve control water volume how many, moreover in aspects and so on energy conservation, constant pressure control had the extremely good effect, this article introduced the frequency changer--PLC regulation technology in water pump control application.
The control system may bring three water pumps with a frequency changer, each water pump already may work in the conventional power frequency pump pattern, also may work in the frequency conversion pump pattern. Each pump only can be in the frequency conversion or the power frequency one kind of working pattern, guarantees its safety and the unreliability mutually through two relay locks. System structure as shown in Figure one, the use places in the domestic water pressure transmitting instrument the water pressure signaling regulator, and reports to the police the bound according to and the regulator setting value to compare, delivers a letter the number for PLC and the frequency changer, the system stops the pump separately decided by the regulator low pressure limit signal and the frequency changer lower frequency limit signal, if the pressure is low, the regulator for a PLC low pressure limit signal, the PLC start frequency changer, and causes the first pump to be at the frequency conversion active status, the output frequency increases gradually, passes through a period of time adjustment, if the pressure is also low, by now, PLC let the first pump be at the power frequency conditionThe work, causes the second pump to be at the frequency conversion active status pump, if the pressure is also low, then lets the second pump be at the power frequency condition work, causes the third pump to be at the frequency conversion active status, so analogizes. When the pressure achieved when the regulator upper limit reported to the police the value, the regulator outputs reduces, the frequency changer frequency reduces, lowers to the lower frequency limit setting value, by now the frequency changer gave a lower frequency limit signal the principle which opened first for the PLC, PLC basis stops first to control the pump the movement order, when for example, PLC received the lower frequency limit signal, in the system the pump condition was a power frequency, two power frequencies, three frequency conversion, the first pump first started by now, therefore stopped first, like the pressure also was then high then stopped the second pump. The system used all has each time carried on the low speed to start, the high speed movement enhanced the operating efficiency.
Uses the frequency changer - PLC constant pressure water supply installment to have following several merits:
A:The electricity saving benefit is high. The traditional water pump electrical machinery uses the large capacity electrical machinery, is constant with the valve control water volume, creates the electrical energy waste.
Frequency conversion system, regardless of the operational parameter how, the electrical machinery efficiency can"t reduce, the electrical machinery power factor can obtain the enhancement.
B:Moves is reliable, is stable. In the system core part - frequency conversion velometer itself reliability is very high, in the ordinary circumstances may the long-term usage 100,000/Above h. The system also selects the soft start method, does not have the electrical impact, does not pollute the electrical network, moreover frequency changer bringing owes presses, the pressure, the overflow, the overload, superheat as well as loses speed and so on each kind of protection function. The system adopts damping filter processing to the pipe network fluctuation of pressure, the water supply constant pressure precision is high, usually can control in the 0.002Mpa scope.
C:The structure is simple, the operation is simple. The installment control system uses the integration rate to be high, necessary plan nimble diverse, obtains water pump movement each kind of combination by the programmable controller. The velocity modulation scope is broad, to water volume change adaptiveness.
D:The service life is long, the automaticity is high, does not need the human to safeguard, maintains the quantity to be few.
Above system the effect is remarkable in the actual application, if brings in PLC and the frequency changer the programmer the function integration, potential becomes some special-purpose frequency changers, such system reliability and the toughness big enhancement, the application is simpler, the system total cost also can drop.
May foresee: The future frequency conversion technology will be able to develop to the below direction:
(1) high performance
Thus including internal leveling circuit, the contravariant electric circuit all use the high frequency PWM electric circuit to cause the input, the output all are sine waves; Uses the multi-densification regarding the large capacity frequency changer and many machine is parallel; Reduces frequency changer own loss, the realization high efficiency; Realizes autotune or from the optimization, the remote control and controls far; Even more faces the user, further enhances the workability and Maintainability: Turns towards, the featherweight development small, as well as reduces the cost and so on.
(2) intellectualization
Including two aspects: Reduces the hardware as far as possible, realizes the hardware software; Uses the intelligent electric power electronic device and other intellectualized part. The integration is the intellectualized foundation.
(3) entire digitization
In recent years, each kind of modern control theory, the expert system, the fuzzy control and the neuron control and so on all were the development hot spots, will cause the electric power electronic control technological development to a brand-new stage. Estimated the 21st century entire numerical control the application will be more widespread thoroughly, even will substitute for the simulation control.
(4) systematization
Frequency conversion technology development is inseparable from the development of related technologies, frequency conversion technology development in the 21st century is to grid, regulators, rely machine, electric motors, production machinery and control systems as a whole, from the system for consideration.
變頻器-PLC在供水控制系統的應用
目前，在水位控制中有很大一部分水泵電機是不變速拖動系統，不變速電機的電能大多消耗在適應供水量的變化而頻繁的開停水泵中。這樣不但使電機工作在低效區、減短電機的使用壽命，而且電機的頻繁開停使設備故障率很高，導致水資源嚴重浪費，系統的維護、維修工作量較大。???? 隨著高位生活用水和工業用水逐漸增多，傳統的控制方法已經落后。原先用人工進行水位控制，由于無法每時每刻對水位進行準確的定位監測，很難準確控制水泵的起停；使用浮標或機械等水位控制裝置使供水狀況有了一些改變，但由于機械裝置的故障多，可靠性差，給維修帶來很大的麻煩。???? 變頻技術以其在節能與恒壓方面的優越性能可以解決水壓控制系統存在的以上問題。考慮選用單片機或PLC與變頻器結合為核心構成的系統都能達到較好的控制效果。但在軟件設計上，PLC比單片機的編程更簡潔、直觀；從硬件接口考慮，單片機電路稍微復雜一些；從經濟方面考慮，由于PLC工藝的日漸成熟，小型PLC的成本與單片機相差無幾，由于要根據現場情況調整系統參數，PLC的軟件中時間參數的調整更簡單，這樣更有利于售后服務人員掌握。基于以上原因，選用了OMRON的 CPM1系列PLC與ABB的變頻器作為控制核心，再加上PSW7調節器與WSP300壓力變送器，控制效果非常好，軟件設計簡單，硬件接口簡易可行、可靠性高，整個系統的性價比非常高。???? 在供水系統中引進變頻器結合小型PLC技術，不僅改變傳統用閥門控制水量多少，而且在節能、恒壓控制等方面均有非常好的效果，本文介紹了變頻器--PLC調控技術在水泵控制中的應用。
控制系統用一臺變頻器可以帶三臺水泵，每臺水泵既可以工作在常規工頻泵模式，也可以工作在變頻泵模式。每臺泵只能處于變頻或工頻其中一種工作模式，通過兩個繼電器互鎖保證它的安全與可靠。系統的結構如圖一所示，利用安置在的生活用水中的壓力變送器將水的壓力信號傳輸到調節器，根據與調節器的設定值和報警上下限比較，送信號給PLC與變頻器，系統的起停泵分別由調節器的壓力下限信號和變頻器的頻率下限信號決定，假如壓力低，調節器給PLC一個壓力下限信號，PLC啟動變頻器，并使一號泵處于變頻工作狀態， 輸出的頻率逐漸增大，經過一段時間的調節，如壓力還低，這時，PLC讓一號泵處于工頻狀態工作，使二號泵處于變頻工作狀態泵，如壓力還低，則讓二號泵處于工頻狀態工作，使三號泵處于變頻工作狀態，如此類推。當壓力達到調節器上限報警值時，調節器輸出降低，變頻器頻率降低，低到頻率下限設定值，這時變頻器給出一個頻率下限信號給PLC，PLC根據先啟先停的原則控制泵的運行順序，例如，PLC收到頻率下限信號時， 系統中泵的狀態是一號工頻，二號工頻，三號變頻，這時一號泵最先啟動，所以先停，接著如壓力還高，則停二號泵。系統采用了每次都進行低速啟動，高速運行以提高運行效率。
采用變頻器-PLC恒壓供水裝置有以下幾個優點：????A:節電效益高。傳統水泵電機均采用大容量電機，用閥門控制水量恒定，造成電能浪費。????變頻系統，無論工作參數如何，電機的效率不會降低，電機的功率因數會得到提高。????B:運行可靠、穩定。系統中的核心部件—變頻調速器本身的可靠性很高，一般情況下可連續使用10萬/h以上。系統還采用軟啟動方式，不存在電氣沖擊，不污染電網，而且變頻器自帶欠壓、過壓、過流、過載、過熱以及失速等各種保護功能。系統對管網壓力波動采取阻尼濾波處理，供水恒壓精度較高，通常能控制在0.002Mpa范圍內。????C:結構簡單，操作簡便。裝置的控制系統采用集成度高，配套方案靈活多樣，由可編程控制器得到水泵運行的各種組合。調速范圍廣，對水量變化的適應能力強。????D:使用壽命長，自動化程度高，無需人看管，維護量少。???? 以上系統在實際的應用中效果顯著，如將PLC與變頻器中自帶編程器的功能集成，可開發成一些專用的變頻器，這樣系統的可靠性與健壯性大大增強，應用更加簡單，系統的總成本也會下降。
可以預見：未來的變頻技術會向以下方向發展：????(1) 高性能化???? 包括內部的整流電路、逆變電路都采用高頻PWM電路從而使輸入、輸出都是正弦波；對于大容量變頻器采用多重化和多機并聯；降低變頻器自身損耗，實現高效率化；實現自動調諧或自優化、遙控和遠控；更加面向用戶，進一步提高可使用性和維修性：向著小型、輕量發展，以及降低成本等。????(2) 智能化???? 包括兩個方面：盡量減少硬件，實現硬件軟件化；采用智能電力電子器件和其他智能化部件。集成化是智能化的基礎。????(3) 全數字化???? 近年來，各種現代控制理論、專家系統、模糊控制及神經元控制等都是發展的熱點，將使電力電子控制技術發展到一個嶄新的階段。預計21世紀全數字控制的應用將更加廣泛深入，甚至取代模擬控制。????(4) 系統化???? 變頻技術的發展與其相關技術的發展是分不開的，在21世紀變頻技術的發展是將電網、整流器、逆變器、電動機、生產機械和控制系統等作為一個整體、從系統上進行考慮的。
出處：陳少雄 趙霞 變頻器-PLC在供水控制系統的應用 (南京工業大學信息學院控制工程中心) >
第2篇: 情書英文翻譯
如何提高物理教學效率
摘要：素質教育"，"減負"等作為當前教育工作，有一個基本的要求。筆者根據的教學實踐研究如何調動的熱情學生和提高的課堂教學效率等問題進行了討論。
關鍵詞：激發興趣，學習能力，課堂教學效率
1.學生的物理學習興趣，提高課堂教學效率
學生在對尋求獲得某種意義的事情感興趣，這在學生的學習活動中發揮了關鍵作用。如果學生有一個感興趣的學習對象，將有效地提高他們的學習效率。同時，學習興趣，也有效地減輕學生的心理壓力，極大的學習熱情可以產生積極的學習動機，教師可用多種教學方法，激發學生的學習興趣。
2.利用物理實驗提高學生的學習興趣
? 物理學本身是一個實驗性的基礎自然科學，物理定義，定理，法律，法律是建立在大量的實驗和實踐活動。課堂的實驗教學可以多次使用，可利用實驗室設備，你也可以利用自制教具，甚至可以利用現有項目，聯系我們的日常生活進行實驗。學生可經常使用的常見的物體（如用鉛筆和三角板做的壓力實驗，用的紙張和橡膠做慣性實驗，用紙張之間的進行流體的壓力和流率的實中，用雪碧做深度與流體壓力之間的關系的實驗，用平板玻璃和造紙做實驗，用雞蛋和鹽物體浮沉做實驗等）做實驗，通過這些學生更加熟悉設備，將物理和生命緊密聯系在一起，學生的學習興趣自然是濃厚。
3.利用多媒體，使用各種教學方法，提高學生的學習興趣
教師在教學中，根據學校的辦學條件，不斷創建物理環境，不僅激發了學生的學習興趣，同時也使學生從弱到強，將興趣的發展始終貫穿的學生，使學生產生學習積極性和主動性，調動學生在這方面的積極性和主動性，合理利用多媒體可以起到顯著的效果。
例如：“浮沉條件的研究對象”，首先利用學生的好奇心理，使學生猜測：一個雞蛋在水槽的底部或浮在水面上？學生很快就討論起來，老師可以用多媒體介紹這個物理實驗，要求學生仔細觀察現象：a：將生雞蛋放入一個盛滿水的燒杯中，我發現了一個雞蛋沉在水底;b：只有一個雞蛋，然后放入鹽水，蛋浮在水面上。學生通過投影機在大屏幕上看到如此大的反差的實驗結果超出自己的想象的時候，所有的人都非常驚訝和興奮的嘗試，這創造了的濃厚興趣氛圍，讓學生參與討論，然后讓學生用設備（橡皮泥，塑料球，金屬球，水，鹽，彈簧秤等）勘探，所有的學生和教師積極參與，教師掌握學生的心理特點，及時提出與相關知識的課件，讓學生討論的對象是漂浮或下沉的原因和他們之間的內在聯系來引導困惑的學生，一些實驗視頻的地方，并引導學生觀察和探索與神秘。形成一個熱鬧的學習氛圍，形成學習高潮，以方便學生完成的猜測 - 觀察 - 思考 - 探索 - 認知的思維過程，學生會對探到的結果感到興奮和自豪，從而是教師和學生都得到認可。這樣的過程不僅培養了學生的學習興趣，同時也學到了知識，同時也給學生成功的喜悅，從而大大提高了學習效率。
4.通過教師的教學媒介激發學生的興趣。
教師的知識越淵博，教師對教材和教學方法來控制的能力越強。蘇霍姆林斯基曾談過一個發人深省的故事：
史老師公共課非常成功，他的每一句話都有很大的吸引力。附近學校老師問他是否準備這節課花了多長時間，他回答說：“這節課我準備了一輩子。一般情況下來說，每一節課，我是用一個生命的時間來準備。但是，關于這個問題，或直接的準備，只有大約15分鐘。”這個故事說明，細節十分重要。只有努力擴展教師的知識，認真琢磨教學藝術，為了引導學生保持學習興趣，才能提高課堂教學的有效性。
教書育人沒有風格，就不能享受學習的過程。現代老師講課，如果能夠讓我們自己的授課既顯得幽默，俏皮，但也不乏邏輯和科學，那學生就愿意傾聽并且他們的高度關注，因此，他們將獲得更寬松的環境知識，有助于技能的增加。因此，對于活潑好動，好奇和敏感的中學生，學習興趣激發出來是很容易被激發的。
我總是把一些成語，典故，以吸引學生，例如講解平面鏡時，引導學生在本節中回憶自己的童年和研究“猴子撈月亮”，成語“假警報”等。研究光的傳播可以直接對話“鑿壁偷光”的故事。
此外，例如，它常常給他們日常的一些遭遇往往是錯誤的，但很容易理解的現象，顯示這些例子，使他們的聲音雖然容易理解，但也很有趣。
例如，在研究熱現象，學生常說的增加或減少的溫度上升或下降，將吸熱或放熱所述，以減少加熱或熱，但幾乎是是同樣的意思，但同樣的不符合的物理意義。我舉這個例子：我寫的：張三，李四是一個胖子一個瘦子，粗脂肪與少，薄，細，我們簡單地說，張三粗人會說，瘦的人得到李四，你同意？在學生哄堂大笑，效果自然可想而知了。
其次，培養學生能力的學生在課堂上積極發揮主體作用來提高的課堂效率，
雖然它長期以來一直認為，素質教育，可持續發展教育，學生主體角色的重要性，新的教育思想，但傳統的教育，教學和考試制度的選擇決定的人必須讓所有學生相同的時間來完成同樣的學習內容。
相反，應試教育仍然是當前教育的主流。我們可以做的是盡可能實施素質教育的應試教育，可持續發展教育，使學生的主體盡可能地發揮作用，調動學生的積極性和提高教學效率，降低降低應試教育的負面影響。
為了培養學生的思維能力，充分發揮學生的主體作用，筆者不斷地在教學中引導學生從物理多維方向研究自然現象，通過問題鼓勵學生獨立探索和實踐，加強學校間的合作，通過學習討論，探索，分析，推理等一系列動手解決身體，心理活動上的問題，達到學習物理知識的目的。
例如：學習連接設備的原則，可能會要求學生先觀察和思考為什么它總是口茶鍋與蓋保持相同的高嗎？思考確定的目標，讓學生觀察和了解，茶壺壺身口兩個容器的物理構成。老師把茶壺壺嘴拆下來讓學生猜第一次安裝后試水的問題，然后再啟發學生在鍋里前嘴套接上準備好的空心圓筒形殼體的折紙，連接水質檢測設備，學生觀察到壺身的長度很短，高度高，很難隨意倒入水，水將不再從壺嘴溢出，從而啟迪學生。
在教學中，我經常將實際的課程內容和學生聯系，學生靈感，靈感來自于利息的疑慮和問題為主要視覺呈現引靈感啟發和改變的啟發，以解決困難的問題，如方法的選擇，盡可能討論調查的問題，設計新的和有趣的地方。
如：在看“相對運動”，筆者往往借詩：滿眼風暴閃爍，看山，看上去就像走路歡迎，仔細看山不動，是乘船游覽。結合地圖使用情景誘導思維。這不僅直觀，形象生動，而且在思維和推理的過程中可以督促學生愛我河山，向往美麗的感情的藝術，極大地增強和激發學生學習物理的興趣。
在理論與實際的社會實踐活動中，筆者試圖做同樣的。
例如：學習“簡單機械”一章中，筆者讓學生復習以往的研究摩擦和壓力的知識，了解杠桿和滑輪，我們發現一些學生缺乏對現實生活的觀察，做不明白自行車的構造，所以我通過自行車的構建進行實踐，有些學生在家里和拆除自行車，了解它的結構;有的大家在一起觀測自行車維修修復過程。
參考文獻：
[1]教育部.初中物理課程標準標準[S].北京：人民教育出版社，2003.
[2]朱永新.新的教育夢想[M].北京：人民教育出版社，2004.
[3]李蕾.使物理課堂充滿生命能量[J].高中物理，2005，（6）。
How to improve the efficiency of physics teaching
Abstract: "Quality Education", "burdens" is the current education work, etc., have a basic requirement. Based on the author"s teaching practice on how to mobilize the enthusiasm of students and improve the efficiency of classroom teaching and other issues were discussed.
Key words: excited interest; learning ability; classroom teaching efficiency
1. by students of physical interest in learning, improve classroom teaching efficiency
Students interested in seeking access to some kind of sense of things, the tendency of its students to play a key role in learning activities. If the student had a learning object interest, their learning efficiency will be effectively raise. The same time, interest in learning, but also effectively reduce the psychological pressure on students to learn to enjoy as a pleasant, resulting in active learning motivation has shown great passion for learning. Can be used in teaching a variety of methods to stimulate students interest in learning.
2.The use of physical experiment to improve student interest in learning
Physics itself is an experimental basis in natural science, physical definition, theorems, laws, laws are built on a large number of experiments and practical activities. Experimental teaching in the class can also be in class the next; can be used with laboratory equipment, you can also bring their own Zizhijiaoju can even use the existing items in our everyday life experiment. Students frequently used items close to experiment (such as a pencil and set square to do with the pressure experiments, using paper and rubber to do inertia experiment to do with the paper the relationship between fluid pressure and flow rate experiments, we use Sprite to do with the depth of the relationship between fluid pressure experiments, using flat glass and paper atmospheric pressure there is to do experiments, eggs and salt with objects floating and sinking experiments to do, etc.), students are more familiar with the equipment , the physical and life are closely tied to students natural interest in learning is well excited.
3.The use of multimedia to improve student interest in a variety of teaching methods
Teachers in teaching, according to the needs of school conditions and continuously create physical environment can not only stimulate students interest in learning, but also enable students from weak to strong interest in the development of teaching has always been throughout the students, there has been interest in the learning enthusiasm and initiative, in mobilizing the enthusiasm and initiative of students in this aspect, the rational use of multimedia can receive significant effect. For example: the research "objects floating and sinking conditions", the first use of the psychological curiosity of students to enable students to guess: an egg is the sink to the bottom or float on water? Students to discuss the atmosphere will warm up quickly, just as the students argue, teachers stand in the multimedia presentation of the physical experiment, ask students to carefully observe the phenomenon has occurred:
a: raw eggs will be put into a beaker filled with water, I found an egg submerged in the bottom;b: only an egg and then into brine, the egg is floating on the surface.
Students through the projector on the big screen to see such a large contrast between the experimental results beyond their own imagination, when, all of them are extremely surprised and excited to try it, which created a thick atmosphere for students to participate in the inquiry, and then allow students to use equipment (rubber cement, plastic balls, metal balls, water, salt, spring balance, etc.) hands-on exploration, the participation of all students and teachers the right to seize the opportunity to master the psychology of students recovering source rooting timely courseware presented with the relevant knowledge, to enable students to discuss the object is floating or sinking reason and reflect on their intrinsic connection between a student confused, the place for some experimental videos, and guide students to observe and explore and mystery. Students interested in learning a lively atmosphere, forming the climax to learn to facilitate students in learning from the inquiry to complete guess - Observer - Reflections - exploration - the cognitive thought process to a conclusion, students explore the results can be for their own teachers and Students recognized and feel excited and proud. This will not only train the students interest, but also to learn the knowledge, but also give students the joy of success, which greatly improves learning efficiency.
4. Through the medium of instruction of teachers to stimulate student interest in infectious
The wider the knowledge of teachers,teaching materials and methods to control the capacity of the stronger. Suhomlinski had talked about a thought-provoking story:
A history teacher lesson highly successful public courses, and his every word has a great appeal. When the lectures of the neighborhood school teacher asked him if he prepared this lesson how long it took, he replied: "This lesson I prepared for a lifetime. And in general, for each class, I have been a life-time to prepare for. However, the direct preparation on this subject, or site preparation, only about 15 minutes."
This story illustrates that only the plot to thin thick hair truth. Only by striving to broaden the knowledge of teachers, seriously pondering teaching art in order to guide students to keep the interest in learning and improve classroom teaching effectiveness.
Teach people not been in style, just will not enjoy learning. Modern teacher lectures if we make their own medium of instruction both seem humorous, witty, but also no lack of logic and scientific, so that students are willing to listen and to lead their high level of attention so that they will receive a more relaxed environment of knowledge, an increase of Skills . Thus, for lively, curious and sensitive middle school students, interest in learning is very easy tobe excited out.
I always bring some idioms, such as allusions to attract students, talk about the first plane mirror to guide students in this section the author recalls his childhood and studied the "monkeys fishing for the moon", and idioms "False Alarm" and so on. Studies of light propagation straight talk "cutting the wall to steal light" story.
Also, for example, it often give some of their daily encounter often wrong but easy to understand the phenomenon, and to visualize these examples so that they sound as though easy to understand, but also interesting.
For example, in studying thermal phenomena, students often say that increase or decrease the temperature increase or decrease will be endothermic or exothermic said to reduce heating or hot, although the meaning is almost, but the same does not meet the physical meaning. I cited this example: I wrote: Zhang San is a fat man, John Doe is a scrag, crude fat with less, thin and fine, for we simply say that the Zhang San yokel would say that thin people get John Doe, You agree? After the students roared with laughter, the effect of natural imagine.
Second, by developing the students ability to actively play the main role of the students in the classroom to improve the efficiency of
While it has long been understood that quality education, education for sustainable development, the role of students in the main body of the importance of new educational ideas, but the traditional educational, teaching and examination system of selection decisions people must be allowed to all students at the same time to complete the same learning content.
Rather, the exam-oriented education is still the mainstream of current education. What we can do is the premise of how the examination- oriented education as far as implementation of quality education, sustainable development of education,the main body of the students as much as possible to play a role in mobilizing the enthusiasm of students and improve teaching efficiency and reduce examination-oriented education negative effects.
In order to cultivate student"s thinking ability, give full play the main role of the students, the author constantly guide the students in the teaching of the need to study the physical multi-dimensional observation of natural phenomena, ask questions, encourage students to independently explore and learn in practice and secondary schools, secondary schools in cooperation, through the "the discussion to explore" analysis, reasoning and a series of hands-on practice of mental and physical, mental activities, to solve problems, learn the purpose of physical knowledge.
For example: to learn principles of connected devices, may require students to first observe and think why it always mouth the tea pot with lid to maintain the same high? Thinking identified targets, with questions for students to observe the physical and understand that teapot by Royal Coffee Pot and mouth two containers constitute the teacher to produce a teapot spout removed to enable students to guess the first post- installation water test, and then to enable students in the pot before the mouth socket class prepared hollow cylindrical casing of paper folding, making changes in the length of the mouth of water testing equipment to enable students to observe the Royal Coffee Pot is short, and will be difficult to arbitrarily pour water, height ofthe , the water will not fill out the phenomenon from the spout so as to enlighten the students.
In teaching, I often combine the actual course content and students, by students as the main visual presentation inspired by, "doubts and questions inspired by interest cited inspired to inspire and change inspired to tackle difficult problems such as the choice of methods, as much as possible to discuss the inquiry the problem, designing new and interesting places.
Such as: In looking at "relative movement", the writer often borrowed poem: eyeful storm more flashes, see the mountains, looking like walking welcome, a close look at Mountain does not move, is a boat trip. Combined with a map Using scenarios induced thinking. This will not only intuitive, vivid image, but also in determining the course of thinking and reasoning can urge students to the ground, love me, rivers and mountains, longing for the art of beautiful feelings, greatly enhance and stimulate student interest in learning physics.
In the theory with the actual social practice activities, the author tried to do the same.
For example: learning "simple machines" one chapter, the author in allowing students to review the previous studies related to friction and pressure of the knowledge, understanding of the levers and pulleys, we found some students the lack of real-life observation, do not understand the bike construction, so I layout of the corresponding social practices. Some of the students at home and dismantled bicycles, understand its structure; others came together to share observations bicycle repair repair process.
References:
[1] Ministry of Education. Junior high school physics curriculum standards [S]. Beijing: People"s Education Press, 2003.
[2] Zhu Yongxin. The new education dreams [M]. Beijing: People Education Press, 2004.
[3] Li Lei. So that the physical classroom full of life energy [J]. High school physics, 2005 (6).
第3篇: 情書英文翻譯
大連民族學院
畢業設計（論文）外文翻譯
學 院： 信息與通信工程
專 業： 電子信息工程
班 級： 電子09級5班
學生姓名： 陸煜
指導教師： 王都生
完成時間： 2013 年 4 月 19 日
3
Code acquisition
3.1 OPTIMUM SOLUTION
In this case, the theory starts with a simple problem where, for a received signal r(t) =
s(t, θ ) + n(t), we have to estimate a generalized time invariant vector of parameters θ
(frequency, phase, delay, data, . . .) of a signal s(t, θ ) in the presence of Gaussian noise
n(t). The best that we can do is to ?nd an estimate θ of the parameter θ for which the aposterior probability p(θ /r) is maximum; hence the name maximum aposterior
probability (MAP) estimate. In other words, the chosen estimate based on the received
signal r is correct for the highest probability. Practical implementation requires us to
locally generate a number of trial values θ , to evaluate p(θ /r) for each such value and
then to choose θ = θ for which p(θ /r) is maximum. In this chapter, we focus only on
code acquisition and parameter θ will include only code delay θ = {τ } and become a
scalar. Analytically, this can be expressed as
Very often, in practice, evaluation of p(θ /r) in closed form is not possible. By using the
Bayesian rule for the joint probability distribution function
and assuming a uniform prior distribution of θ , maximizing p(θ /r) becomes equivalent
to maximizing p(r/θ ), a function that can be determined more easily. This algorithm is
known as maximum likelihood (ML) estimation and can be de?ned analytically as
It is straightforward to show that in the case of Gaussian noise, the ML principle necessi-
tates the search for that value of θ that would maximize the likelihood function de?ned as
where s(t, θ ) is the locally generated replica of the signal with a trial value θ . For
the given signal power, the second term in the previous equation is a constant so that
the maximization is equivalent to the maximization of the ?rst term only. This can be
expressed as
Instead of searching for the maximum of λ(θ ) in a so-called open loop con?guration, an
equivalent procedure would be to ?nd the zero of the ?rst derivative of λ(θ )
This structure is known as the maximum likelihood tracker (MLT). In practice, the signal
derivative is often approximated by the signal difference
where s(t, θ + θ ) and s(t, θ ? θ ) are so called early and late versions of the local
signal with respect to the generalized parameter θ to be estimated. This results in the
so-called early–late tracker
where
In the case of code synchronization, θ = τ and the ML synchronizing receiver implied by
equation (3.5) should, in principle, create all possible time-offset versions of the known
code waveform, correlate all of them with the received data and choose the τ corre-
sponding to the largest correlation as its estimate, τML . Owing to the continuous range
of values of τ , this is not possible in practice and some type of range quantization is
necessary. The resulting candidate values are called cells, and the initial parameter esti-
mation problem is translated into a multiple-hypothesis problem: to locate the cell most
likely to contain the unknown offset, given this piece of data. This is exactly the coarse
code synchronization or code acquisition problem, the result of which is to resolve the
code phase (or the ‘epoch’) ambiguity within the size of the cell. Since this remaining
error is typically larger than desired, further operations are required in order to reduce
it to acceptable levels. This remaining part of the synchronization task, namely, that of
?ne synchronization or code tracking, is performed by one of the available code-tracking
loops, which we discuss in the next chapter.
Once the nature and size of these cells have been determined, the next question is how
to go about performing the search most successfully. Clearly, the strategy will depend on a
variety of factors such as criteria of performance, degree of complexity and computational
power available (directly related to cost), prior available information about the location of
the correct cell and so on. A brute-force approach would try to create a bank of parallel
correlation branches, each matched to a possible quantized value of the timing offset;
it would then process the received waveform through all of them simultaneously, pick
the largest and declare a candidate solution. Unless the uncertainty region (number of
cells) is small, corresponding to either a small code period or a small initial uncertainty,
such a solution (which we may call the totally parallel solution) becomes obviously
unwieldy in complexity very quickly. We note, however, that small uncertainty regions
may be encountered in a nested design, whereby a multitude of different-period codes are
combined for precisely the purpose of aiding acquisition. Furthermore, neural network
structures are currently being explored for this purpose, where the neural network is
trained for all possible such values. Such a scheme would emulate the spirit (if not the
exact statistical processing) of the above solutions.
3.2 PRACTICAL SOLUTIONS
In practice, most of the time total parallelism is out of the question when the number
of cells is very large (although it appears doable for smaller uncertainty regions) and
simpler solutions are necessary. One of the most familiar of such approaches is the
simple technique of serial search, where the search starts from a speci?c cell and serially
examines the remaining cells in some direction and in a prespeci?ed order until the
correct cell is found. Hence, serial search techniques do not account for any additional
information gathered during the past search time, which could conceivably be used to
alter the direction of search toward cells that show increased posterior likelihood of being
the correct ones. A serial search starts from a cell that could be chosen totally arbitrarily
(no prior information), or by some prior knowledge about a likely cell, and proceeds
in a simple and easily implementable predirected manner. When the uncertainty space
(collection of all possible cells) is two-dimensional (delay and frequency offset) and
searching all possible cells serially appears to be very time consuming, a speedup may
be achieved by employing a bank of ?lters, each matched to a possible Doppler offset.
The same idea can be applied to the one-dimensional case (no frequency uncertainty),
where now a bank of correlators may be employed, each starting from a different point of
the uncertainty region. This effectively amounts to dividing the search in many parallel
subsearches and therefore reducing the total search time by a proportional amount.
One should be aware that although it holds true that only one cell contains the exact
delay and Doppler offsets of the incoming code, the set of desirable cells acceptable to
the receiver includes a number of cells adjacent to the exact one. Indeed, the receiver will
terminate acquisition and initiate tracking, the ?rst time a cell is reached (and correctly
identi?ed), which is close enough to true synchronization so that the tracking loop can pull
in and perform the remaining synchronization operation successfully. All these desirable
cells are collectively called hypothesis H 1 , and the remaining nondesirable ‘out-of-sync’
cells comprise hypothesis H0 . As an example, consider the case in which the receiver
examines the code delay uncertainty in steps of half a chip time (δt = Tc /2) and there
is no frequency uncertainty. Then, all four cells located in the interval (?Tc , Tc ) around
the true delay of the incoming code are included in hypothesis H1 , since some amount
of code correlation exists for each one of these cells, an amount that can initiate the
code-tracking loop.
The above de?nition of cells and hypotheses implies that each test does not pertain
to a single value of the unknown parameter τ , but rather to a range of values. It is
straightforward to show that, under mild conditions and approximations pertaining to the
pseudorandom nature of the code, this reformulated hypothesis testing results in a statistic
(correlation) and threshold setting that do not depend on the given (tested) value of the
unknown parameter (a uniformly most powerful test). This is because the threshold value
is set by the desirable probability of false alarm per cell (see below), which is independent
of τ under H0 .
To recapitulate, the two-dimensional time/frequency code offset uncertainty within the
noisy received waveform is quantized into a number of cells, which are typically searched
in a serial fashion by a correlation receiver, although parallel multiple branches are also
possible. Motivated by an ML argument, the receiver creates a cross-correlation between
the incoming waveform and the local code at a speci?c offset, whose output is used to
decide whether the currently examined cell is a desirable (H1 ) one. The process continues
until one such cell is correctly identi?ed. At that point, acquisition is terminated and
tracking is initiated.
3.3 CODE ACQUISITION ANALYSIS
The serial code acquisition can be represented by using the signal ?ow graph theory. Each
cell is represented by a node of a graph and transitions between the nodes depend on the
outcome of the decision in a given cell. Branches connecting the nodes characterize these
transitions. To motivate the operation in a transform domain, let us consider the simple
model of a process represented by the graph in Figure 3.1 and evaluate the probability
pac (t) that the process will move from a to c in exactly t seconds.
To do this, we will introduce an additional variable τ to designate the time needed for
the process to move from a to b, characterized by the probability pab (τ ). The parameter
pac (t, τ ) represents the joint probability that the process moves from a to c in t seconds
and takes τ seconds to move from a to b. This probability can be represented as
resulting in
In other words, the overall probability pac (t) is a convolution of the two intermode
transition probabilities pab and pbc . It is clear that for the graph with a large number
of nodes we will have to deal with multiple convolutions giving rise to computational
complexity. In this case, people being involved in electrical engineering prefer to move to
a transform domain, either Laplace (s) domain for continuous variables or into z-domain
for desecrate variables. This leads to using z-transform for the decision process ?ow graph
representation and multiple convolutions will be now replaced with multiple products
making the calculus much simpler. If pij (n) is the probability for the process to move
from node i to node j in exactly n steps, then its z-transform
is called the probability generating function. For the analysis to follow, we will need a
few relations derived from this de?nition. First of all, the ?rst and the second derivative
of this function can be represented as
By de?nition, the average number of steps to move from node i to node j is
and the average time to do it can be represented as
where T is the cell observation time that is, the time needed to create the decision variable
that will be referred to as dwell time. For the variance, we start with the de?nition
The second derivative of the generating function can be represented as
By using equations (3.15) and (3.18) in equation (3.17), the variance of time tij can be
expressed in the following form:
In what follows, we will use these few relations to analyze serial search code acquisition.
In order to get an initial insight into this method, we will assume that there are q cells to
be searched. Parameter q may be equal to the length of the pseudonoise (PN) code to be
searched or some multiple of it. For example, if the update size is one-half chip, q will
be twice the code length to be searched. Further assume that if a ‘hit’ (output is above
threshold) is detected by the threshold detector, the system goes into a veri?cation mode
that may include both, an extended duration dwell time and an entry into a code loop
tracking mode. In any event, we model the ‘penalty’ of obtaining a false alarm as Kτd
second and the dwell time itself as τd second. If a true hit is observed, the system has
acquired the signal, and the search is completed. Assume that the false alarm probability
PFA and the probability of detection PD are given. We will also assume that only one cell
represents the synchro position. Let each cell be numbered from left to right so that the
kth cell has a priori probability of having the signal present, given that it was not present
in cells 1 through k ? 1, of
The generating function ?ow diagram is given in Figure 3.2 using the rule that at each
node the sum of the probability emanating from the node equals unity. The unit time rep-
resents τd seconds and Kτd seconds are represented in z-transform by zK . Consider node
1. The a priori probability of having the signal present is P1 = 1/q, and the probability
of it not being present in the cell is 1 ? P1 . Suppose the signal was not present. Then we
advance to the next node (node 1a); since it corresponds to a probabilistic decision and
not a unit time delay, no z multiplies the branch going to it. At node 1a a false alarm
may occur, with probability PFA = α. This would require one unit of time to decide (τd s)
and then K units of time (Kτd s) are needed in veri?cation mode to determine that there
was a false alarm. False alarms will not occur with probability (1 ? α). This would take
one dwell time to decide and is represented by (1 ? α)z branch going to node 2.
出處：Savo G. Glisic, Adaptive WCDMA: Theory and Practice, John Wiley & Sons, Ltd. Chapter 3
第三章 編碼的獲取
3.1 最佳的解答
在這種情況下, 理論可以出一個簡單的問題開始，當接收的信號為，我們必須在有高斯噪聲的情況下，估計信號廣義時的不變向量參數(頻率, 相位, 延遲, 數據, …)。我們所能做的是找出參量θ的估計參量，而其對應的后驗概率是最大，因此命名為最大后驗概率估計。換句話說, 基于所收到的信號r的估計是正確率最高的。實踐要求我們有大量的試驗估值, 并由這些估計值來估計，然后選擇=，使最大。 在這個章節里, 我們只關注碼的獲取，參量將只包括代碼延遲并且將成為一個標量。
由上分析, 可將其表達為：
通常, 實際中,以閉合的形式估計是不可能的。使用貝葉斯準則來求聯合概率分布函數。
并且假定為均勻優先分布, 取最大值與最大值相等，可以更容易的確定一個函數。這種算法通常叫做最大似然估計，被定義為解析式：
顯然在高斯噪聲情況下, 須用最大似然原理來確定值，則最大可能性估計可被定義為：
其中是根據試驗估計得出的信號。對于給定的信號源，上式的第二項是個固定值，所以要想取得最大值只需第一項取得最大值。可表示為
不需要在所謂的開環配置中求最大值，只需求的一階導數為零時對應點的函數值。
這個儀器被稱為最大可能性跟蹤器（MLT）。在實際中，不同信號的導數可近似的表示為
此式中和是當地信號參量θ估計值的前后的樣值。這就是所謂的前后跟蹤器。
其中
在代碼同步情況下，和最大可能性估計同步接收器應該包含在等式(3.5) 中，原理上，創建已知的編碼波形的所有偏移值，根據所有接收的數據選擇有最大交互的值作為它的估計。由于τ值的連續變化，在實際中是不可能，因此某種類型的量子化是必要。前人們把它叫做小區，并且最初的參量估計問題被轉換成多假說問題：定位小區時可能包含不確定的偏移值, 給出偏移值。這就是同步粗捕獲碼或捕獲碼的問題, 也是解決在小區部內碼相位模糊問題。因為這個存在的誤差比想象中的要大的多, 所以應進一步對其進行研究使之減少到可以接受的水平。剩下的就是碼同步問題, 即良好的同步或代碼跟蹤, 可利用我們在下個章節中討論的代碼跟蹤環。一旦這些小區的屬性和大小被確定，接下來的問題是如何更好的進行搜索。很明顯，所選擇的方法將由變化的因素決定，譬如性能標準，復雜程度和有用功率的計算(與消耗功率直接相關)，先前在正確定位小區所需要的信息等等。蠻力計算法會創建一組并行相關的分支, 每個匹配時間偏移量的可能量化值，然后將收到的波形同時進行處理，選出最大的確定備選的解決方法。除非不確定性區域(小區的數量)太小, 對于既不是小代碼周期又不是初期的不確定碼，這種解決方法（完全平行解決法）在快速解決復雜問題中有很明顯的不廣泛性。我們發現, 即使是很小的不定區域在蜂窩網的設計中我們也會遇到，藉以將許多不同期間代碼相結合達到很好的援助獲取的目的。此外, 神經網絡的構建就是為了這個目的, 其中神經網絡的訓練是對所有可能值的。這樣的設計方法可以接近實際(如果不是精確的統計處理)。
3.2實際的解答
實踐中,大多數的時間總對應量在小區的數量非常大時，不在考慮的范圍內(雖然看起來對更小的不確定區域是可行的)而且更加簡單的解答是必要的。一個最熟悉的逼近方法是簡單的連續查尋技術,其中查尋從一個特殊的小區開始然后根據一定方向和指令的順序連續搜索剩余的小區直到找到確切的小區。因此, 連續查尋技術在過去的搜索期間中不占任何多余信息,它可以被用來改變搜索小區的方向，來找出增加的后驗概率使其更加準確。一次連續查尋從一個能完全任意被選擇的小區開始(沒有預先的信息)，或由一些關于一個可能的小區的預先的信息所決定, 并且進行簡單的容易移植預測的方法。當不確定性空間(所有可能的小區的收集)是二維的(延遲和頻率偏置)，而且連續的搜尋所有可能的小區看來非常費時,可以使用一組濾波器來達到增加速度的目的,每個匹配一個可能的多譜勒偏置。同樣對一維的情況，在每個不確定區域的不同點開始引進一組關聯的濾波器。
這種有效的方法是在搜索過程中將其轉換成許多并行的搜索分支，再通過適當的比例來減少總的搜索時間。應注意的是盡管在一個小區中每個下一個碼元都有精確的延遲和多譜勒偏置，接收器所接收的小區的配置中有許多與實際的小區相接近。的確,接收器將結束獲取并且開始跟蹤，小區第一次被獲得(正確地辨認), 使其充分接近完全同步以便跟蹤圈可以進行并且成功地進行剩余同步操作。所有這些中意小區被收集叫做H1假說, 并且剩下的不被中意的非同步的小區組成假說H0。假設接收器在步半個時隙內審查代碼不確定性延遲并且沒有不確定的頻率。然后,所有四個小區位于間隔時間(，)接踵而來的代碼實際的延遲包括在假說H1內，因為在每一個這樣的小區中大量的代碼交互作用是存在的,總值可使代碼跟蹤圈開始。
上述對小區的定義和假說表明，各個測試不附屬未知數的唯一值，是一個變化范圍。在適宜的條件和忽略偽隨機代碼的屬性的情況下，直接表明了，再次形成的假說實驗結果在統計（交互作用）和門限設置上不依靠所給（被測試的）不確定參數(一個公認的最權威測試)的數值。這是因為閾值由假警報可能的要求設置每個小區(參見下面)，其取決于在H0下的值。
由上可知, 二維的時間/頻率代碼在噪聲中接收的信號波形中的不確定偏置被量化成一定數量的小區，其中在一系列的典型搜尋中由交互作用接收器完成，雖然平行并聯支路是可能的。由最大似然估計理論推斷，接收器在具體偏置中將接踵而來的信號波形和當地的代碼產生交互作用。它的輸出被用于決定當前被審查的小區是否是所要求的（H1）。搜索直到找到所要求的那個小區正確的被確認，這時，結束碼的獲取開始碼的跟蹤。
3.3編碼的獲取分析
連續代碼獲取可使用信號流程圖原理來表示。 每個小區由原理圖的結點表示并且在結點間的傳輸過程由指定的小區的輸出端決定。結點間的分支表明了這些傳輸。為了在傳輸區域進行控制，讓我們用圖3.1簡單的說明這個過程，同時計算在t秒時間內，進程由a移動到c的概率。為了說明，在選定由a移動到b過程所需時間時我們引進一個附加變量τ。用概率函數表示。
參數表示了在t秒內，進程由a 移動到c和在秒內有a移動到b 的聯合概率。
可由下式表示：
即得：
換句話說, 整體概率是兩個結點的傳輸概率和的卷積值，顯然在原理圖有大量結點的情況，進行拉普拉斯變換對離散變量進行z域的變換。這使在確定流程圖的畫法時使用變換而不使用卷積來計算取而代之的是使其更簡單的多重積分。如果是由結點由n步移動到結點j這個過程的概率時，則它的z變換可以表示為
叫做概率生成函數。為了接下來的分析，我們得從這個式子得出由其衍生出來的關系，首先，衍生出來的兩個式子可表達為
由定義可知，有結點到結點j的平均數可表示為：
平均時間可表示為
其中T是小區的周期，并且時間需要根據停留時間創建決策變量，為了進一步變化由定義
第二個演變所得的生成函數可表示為
由等式（3.15）和（3.18）的變化時間可以被表示為以下形式：
下面，我們將運用這些關系來分析碼獲取的一系列搜索。為了進一步研究這種方法，我們假設要搜索的有個小區，參數相當于被搜索的偽隨機（PN）碼的長度或者是它的倍數。例如, 如果校正碼的大小是二分之一碼，將是代碼搜索長度的二倍。進一步假設，如果門限探測器發現溢出(輸出超過門限)，系統進入驗證模式，即有兩種方式：延長過壓保護的時間和進入代碼循環追蹤模式。無論如何，我們模擬這種錯誤在我獲得一個假警報和的過壓保護時間時。如果發現真的溢出, 系統已經獲取了信號, 并且查尋已完成。假設, 假警報概率和偵查的概率已給出。我們也可假設只有一個小區與同步位置相符。將每個小區由左到右編號，為了使第個小區得到現有的信號的先驗概率，下式是它從小區１到小區：
生成函數流程圖在3.2給出規則是在每個結點的流出概率與總體流出的概率相一致。
在z變換中單位時間和代表。考慮結點1當前信號的先驗概率為，而且它的概率在第個小區中并不存在。假定信號不存在。然后我們進行下一個結點(結點)；因為它與似然率相一致，并且不是單位時間延遲，沒有和分支相乘。在這個點處，當時可能產生假警報。這會要求在單位時間確定并且在K時間單位驗證模式下為確定一個假警告是必要的。當概率為時假警告不會發生。這會由過壓保護時間決定并表征為分支到結點2。
