光信息科学与技术专业中英文对照外文翻译文献
电子信息工程 外文翻译 外文文献 英文文献 文献翻译
Technology and Application of Fieldbus Control System ---------IntelligentEquipment & Measurement And Control System Based on DeviceNetPromoted by the new technological revolution that automation control technology is tending digitization and internet in the field of automation industry, Shanghai Aton Electric Co., Ltd. developed Intelligent Equipment & Measurement And Control System Based on DeviceNet as a high and new technology industrialization model project. It was a state hi-tech development project of 2000 and was approved by the State Committee of Technology. Shanghai Aton Electric Co., Ltd. constructed production line of intelligent controller of pump and valve, relying on Shanghai Electric (Group) Corporation; constructed measurement and control system FCS R&D center of intelligent controller of pump and valve and built up mass production R&D basis, cooperating with Shanghai Jiaotong University and Shanghai University; constructed FCS remote diagnosis and service center of intelligent controller of pump and valve; constructed FCS training center of intelligent controller of pump and valve; founded mass production R&D basis along with the Rockwell Laboratory of Shanghai Jiaotong University and CIMS Center.1 Summary(1)Fieldbus control system is a system applied to field of production and microcomputerized measurement control equipment to realize both-way multinode serial communications. It is also called low-level control network for open, digital and multiplespot communications.Application: Flow Control System of Manufacturing; Process Control System; Traffic Control & Management; Building Automation. Features: Fieldbus control system is low-level low-bandwidth digital communication and control network in industrial system as well as open system connecting microcomputerized appearance. Intelligent instrument and controller are equal to microcomputer. They make up network with Fieldbus control system as the links to complete digital communication and other tasks.(2)Difference between FCS and DCS,FCS is updated control system after DCS integrated with digital control system and distributing control system. It solves the problem that in traditional DCS, devices made by different manufacturers cannot be connected. They can't realize exchange and operation to organize an network system with wider range of information sharing. It conquers the defect that special closed system for network should be used for communication in DCS to realize various functions of integrated automation. It turns the distributing structure combiningconcentration with deconcentration in DCS into new-type full distributing structure. It releases the control function to the field thoroughly and makes it possible to realize basic control function by means of fieldbus equipment itself. FCS breaks the traditional structure form of control system. The traditional analog control system adopts one-to-one equipment tie-wire and puts up connections respectively according to control loop. FCS adopts intelligent field equipment to place the control module, all input/output modules that used to be in the control chamber of DCS into field equipment. Since field equipment has ability to communicate, the field measuring and transferring instruments can transfer signals to actuating mechanism such as valve directly. Its control function can be fulfilled directly on the spot independent of the computer or control meter in the control chamber, which realizes thorough decentralized control.FCS adopts digital signals to replace analog signals so that multiple signals (including multiple operating parameter values, device status and failure information) can be transferred on a pair of cables. Meanwhile, it can give power supply to several devices. No switched block for analog/digital or digital/analog is needed besides fieldbus.(3)Characteristics of FCS●Open System;●Interoperability;● replace ability of devices made by different manufacturers.● Intelligentize and Autonomy;●Field equipment completing basic functions of automatic control.●Decentralized System Structure;●Field Adaptability;●Relatively Strong Interference Killing Feature and Safety●Intelligentized local equipment can save investment and quantity of hardware●Saving installation expenses and cables●Saving daily maintenance expenses●Enhancing accuracy and reliability of system●Enhancing initiativeness of system integration for users(4)Development Background and Trend of Fieldbus Control System,With the rapid development of computer and computer network, FCS has been rapidly developed as the interlinked communication network between the field intelligentdevices in the field of process automation, building and traffic etc. Because FCS meets the needs that industrial control system is developing in the way of decentralization, network and intellectualized, it has become the focus of global industrial automation and been universally concerned by the whole world. FCS has caused great revolutions on the aspects of system structure and function system for the current production of automation instrument, distributing control system and programmable controller. It is predicted that FCS will be the general trends in a very long time in the future fore sure.2 APPLICATION OF RELAYThe product reliability generally refers to the operating reliability. It is defined as: the ability of accomplishing the specified function under prescribed conditions and in prescribed time. It consists of intrinsic reliability and application reliability. The intrinsic reliability is determined by product designing and manufacturing technique, and the application reliability is concerned with the correct application of users and the services provided by the manufacturer before and after selling. When using relay, the user should pay attention to the following items.2.1 Coil applied voltageIt is best to choose the coil applicative voltage according to the rated voltage in design, or choose the voltage according to the temperature rising curve. Using any coil voltage that is less than the rated voltage will affect the operation of the relay. The coil operating voltage refers to the voltage that is applied between the coil terminals. The voltage value between the two terminals must be guaranteed, especially when using enlargement circuit to energize the coil. Whereas, it will also affect the relay characteristics if the applied voltage exceeds the highest rated voltage. Exorbitant voltage will bring exorbitant coil temperature rising, especially in high temperature ambient. Exorbitant temperature rising will damage the insulating material and affect the working safety of relay. For magnetic latching relay, energizing (or return) pulse width should not less than 3 times of the operating (or return) time, otherwise, the relay would be left on the middle-position state. When using solid-state components to energize the coil, the components dielectric strength must be above 80V, and the leakage of current must be as little as possible to ensure the relay to release.Energizing power source: Under 110% of the rated current, the adjusting ratio of the power source is less than 10% (or the output impedance is less than 5% of the coilimpedance), the wave voltage of the DC power source is less than 5%. The AC wave is sine wave; the waviness coefficient is between 0.95~1.25; wave distortion is within ±10%; the frequency change is within±1Hz or ±1% of the specified frequency (choosing the bigger value). The output power should not less than coil power consumption.2.2 Transient suppressionAt the moment when the coil power is stopped, peak-inverse voltage that is more than 30 times of the coil rated voltage is produced on the coil, which is harmful to the electronic circuit. Generally, the peak-inverse voltage is suppressed by transient suppression（cutting-peak）diode or resistance to limit the peak-inverse voltage within 50V. But the diode in parallel connection will delay3~5 times of the release time. If the request of the release time is high, a suitable resistance in series can be putted with and at one end of the diode.The power supply to relays in parallel connection and series connection,When several relays in parallel connection are supplied, the relay that the peak-inverse voltage is higher will release power to the relays that the peak-inverse voltage is lower. The release time of the relay will delay. So the relays in parallel connection should be controlled separately to eliminate mutual influence.The relays with different coil resistance and power can’t be used in series, otherwise, t he relay that the coil current is higher in the series circuit can’t operate reliably. Only the relays of the same specification can be used in series, but the peak-inverse voltage will be increased and the peak-inverse voltage should be suppressed. Resistance in series can be used to bear the part voltage that exceeds the rated voltage of the coil according to the ratio of the divided voltage.2.2.1 Contact loadThe load applied to the contacts should be accordant to the rated load and characteristics of the contacts. A load that is not applied according to the rated value range will cause problem. The relay that is only suitable for DC load can’t be used in AC occasions. The relay that can switch 10A load can’t always reliably operate in low level load (less than 10m A×6A) or in dry circuit occasions. The relay that can switch single-phase AC power source isn’t always suitable to switch two single-phase AC loads that aren’t synchronous; the relay that is only specif ied to switch the load of AC 50Hz（or 60Hz）can’t be used to switch AC load of 400Hz.2.2.2 Parallel and series connection of contactsThe contacts used in parallel connection can’t increase the load current, because the operating times of several sets of contacts are absolutely different; that is to say, there is still only a set of contacts switching the increased load. This would damage or weld the contacts and make the contacts can’t close or open. The parallel connection of the contacts can decrease t he misplay of “break”. But the parallel connection of the contacts would increase the misplay of “freezing”. Because the misplay of “break” is the main pattern of invalidation of contacts, the parallel connection can increase the reliability and can be used on the pivotal part of equipments. But the applied voltage should not exceed the highest operating voltage of the coil and should not less than 90% of the rated voltage, otherwise, the coil life and the applicative reliability would be damaged. The series connection of the contacts can increase the load voltage. The amount of the contact sets is equal to the times that the load voltage can be increased. The series connection of contacts can decrease the misplay of “freezing”, but it would increase the mis play of “break”. Anyway, when using redundant technology to increase the operating reliability of contacts, the characteristics and size and the failure mode of load must be considered.2.2.3 Switching speedThe switching speed should not exceed the reciprocal of 10 times of the sum of operating and release time (times/s), otherwise, the contacts can’t switch on steadily. Magnetic latching should be used under the pulse width specified in the technique criterion, or the coil may be damaged.3 RVT DISTRIBUTING ELECTRICITY INTEGRATE TESTAPPARATUSBasic functionMeasure asupervision:Three mutually electric voltage/electric current/ power factor with a great achievement/ power without a great achievement/electricity with a great achiverment/electricity/homophonic-wave electric voltage/ homophonic-wave electric/ current Day electric voltage/ electric current biggest and minimum value/fire for the failure Electric voltage over top, the limit/ lack mutually of time homophonic-wave analyzes is up to 13 times.The data is stored for 2 months.The data communicateRS232/485 communicating connect，The way in communicating can adopt the spot communicating or the long range communicating.，Possible to settle invoke orthe solid hour invokes, responding to the modification and long ranges control of the parameter.Without power compensationTaking physics measures as the power factor without a great achievement,the power factor with a great achievement and the dull place without power compensation;Y+ the combination method of the △，Y+ the △connects the line method，Y+ △ , Y, the △ connects the line method.Data managementAccording to WINDOW98 operation terrace, data in communication automatically reports born statement, curve and pillar form diagrams.Circulation of the protectionWhen the charged barbed wire net of mutually electric voltage over press, owe to press, and a super limit hour fast cut off in expiation of capacitor，When the charged barbed wire net lacks mutually or super limit in the preface of zero hour fast cut off in expiation of capacitor.screen manifestationChinese operation interface，Adopt 128*64 the back light liquid crystal display.The solid hour shows the charged barbed wire net relevant parameter.view manifestation to place the parameter.现场总线控制系统的技术和应用随着新的科学技术革命的出现，在自动化工业领域中，自动控制技术的发展趋向于数字化和网络互联化。
(完整word版)光学外文文献及翻译
学号2013211033 昆明理工大学专业英语专业光学姓名辜苏导师李重光教授分数导师签字日期2015年5月6日研究生部专业英语考核In digital holography, the recording CCD is placed on the ξ-ηplane in order to register the hologramx ',y 'when the object lies inthe x-y plane. Forthe reconstruction ofthe information ofthe object wave,phase-shifting digital holography includes two steps:(1) getting objectwave on hologram plane, and (2) reconstructing original object wave.2.1 Getting information of object wave on hologram plateDoing phase shifting N-1 times and capturing N holograms. Supposing the interferogram after k- 1 times phase-shifting is]),(cos[),(),(),,(k k b a I δηξφηξηξδηξ-⋅+= （1） Phase detection can apply two kinds of algorithms:synchronous phase detection algorithms [9]and the least squares iterative algorithm [10]. The four-step algorithm in synchronous phase detection algorithm is in common use. The calculation equation is)2/3,,(),,()]2/,,()0,,([2/1),(πηξπηξπηξηξηξiI I iI I E --+=2.2 Reconstructing original object wave by reverse-transform algorithmObject wave from the original object spreads front.The processing has exact and clear description and expression in physics and mathematics. By phase-shifting technique, we have obtained information of the object wave spreading to a certain distance from the original object. Therefore, in order to get the information of the object wave at its initial spreading position, what we need to do is a reverse work.Fig.1 Geometric coordinate of digital holographyexact registering distance.The focusing functions normally applied can be divided into four types: gray and gradient function, frequency-domain function, informatics function and statistics function. Gray evaluation function is easy to calculate and also robust. It can satisfy the demand of common focusing precision. We apply the intensity sum of reconstruction image as the evaluation function:min ),(11==∑∑==M k Nl l k SThe calculation is described in Fig.2. The position occurring the turning point correspondes to the best registration distanced, also equals to the reconstructing distance d '.It should be indicated that if we only need to reconstruct the phase map of the object wave, the registration distance substituted into the calculation equation is permitted having a departure from its true value.4 Spatial resolution of digital holography4.1 Affecting factors of the spatial resolution of digital holographyIt should be considered in three respects: (1) sizes of the object and the registering material, and the direction of the reference beam, (2) resolution of the registering material, and (3) diffraction limitation.For pointx2on the object shown in Fig.3, the limits of spatial frequency are λξθλθθ⎥⎦⎤⎢⎣⎡⎪⎪⎭⎫ ⎝⎛-'-=-=-0211maxmax tan sin sin sin sin z x f R R Fig.2 Determining reconstructing distanceλξθλθθ⎥⎦⎤⎢⎣⎡⎪⎪⎭⎫⎝⎛-'-=-=-211minmintansinsinsinsin zxfRRFrequency range isλξξ⎥⎦⎤⎢⎣⎡⎪⎪⎭⎫⎝⎛-'-⎥⎦⎤⎢⎣⎡⎪⎪⎭⎫⎝⎛-=∆--211211tansintansinzxzxfso the range is unrelated to the reference beam.Considering the resolution of registering material in order to satisfy the sampling theory, phase difference between adjacent points on the recording plate should be less than π, namely resolution of the registration material.cfff=∆η21)(minmaxπ4.2 Expanding the spatial resolution of reconstruction imageExpanding the spatial resolution can be realized at least in three ways: (1) Reducing the registration distance z0 can improve the reconstruction resolution, but it goes with reduction of the reconstruction area at the same ratio.Therefore, this method has its limitation. (2) Increasing the resolution and the imaging size of CCD with expensive price. (3) Applying image-synthesizing technique[11]CCD captures a few of images between which there is small displacement (usually a fraction of the pixel size) vertical to the CCD plane, shown in Fig.4(Schematic of vertical moving is the same).This method has two disadvantages. First, it is unsuitable for dynamic testing and can only be applied in the static image reconstruction. Second, because the pixel size is small (usually 5μm to 10μm) and the displacement should a fraction of this size (for example 2μm), it needs a moving table with high resolution and precision. Also it needs high stability in whole testing.In general, improvement of the spatial resolution of digital reconstruction is Fig.3 Relationship between object and CCDstill a big problem for the application of digital holography.5 Testing resultsFig.5 is the photo of the testing system. The paper does testing on two coins. The pixel size of the CCD is 4.65μm and there are 1 392×1 040 pixels. The firstis one Yuan coin of RMB (525 mm) used for image reconstruction by phase-shifting digital holography. The second is one Jiao coin of RMB (520 mm) for the testing of deformation measurement also by phase-shifting digital holography.5.1 Result of image reconstructionThe dimension of the one Yuancoin is 25 mm. The registrationdistance measured by ruler isabout 385mm. We capture ourphase-shifting holograms andreconstruct the image byphase-shifting digital holography.Fig.6 is the reconstructed image.Fig.7 is the curve of the auto-focusFig.4 Image capturing by moving CCD along horizontal directionFig.5 Photo of the testing systemfunction, from which we determine the real registration distance 370 mm. We can also change the controlling precision, for example 5mm, 0.1 mm,etc., to get more course or precision reconstruction position.5.2 Deformation measurementIn digital holography, the method of measuring deformation measurement differs from the traditional holography. It gets object wave before and after deformation and then subtract their phases to obtain the deformation. The study tested effect of heating deformation on the coin of one Jiao. The results are shown in Fig.8, Where (a) is the interferential signal of the object waves before and after deformation, and (b) is the wrapped phase difference.5.3 Improving the spatial resolutionFor the tested coin, we applied four sub-low-resolution holograms to reconstruct the high-resolution by the image-synthesizing technique. Fig.9 (a) is the reconstructed image by one low-resolution hologram, and (b) is the high-resolution image reconstructed from four low-resolution holograms.Fig.6 Reconstructed image Fig.7 Auto-focus functionFig.8 Heating deformation resultsFig.9 Comparing between the low and high resolution reconstructed image6 SummaryDigital holography can obtain phase and amplitude of the object wave at the same time. Compared to other techniques is a big advantage. Phase-shifting digital holography can realize image reconstruction and deformation with less noise. But it is unsuitable for dynamic testing. Applying the intensity sum of the reconstruction image as the auto-focusing function to evaluate the registering distance is easy, and computation is fast. Its precision is also sufficient. The image-synthesizing technique can improve spatial resolution of digital holography, but its static characteristic reduces its practicability. The limited dimension and too big pixel size are still the main obstacles for widely application of digital holography.外文文献译文：标题：图像重建中的相移数字全息摘要：相移数字全息术被用来研究研究艺术品的内部缺陷。
光学外文文献及翻译
学号********** 昆明理工大学专业英语专业光学姓名辜苏导师李重光教授分数导师签字日期2015年5月6日研究生部专业英语考核In digital holography, the recording CCD is placed on the ξ-ηplane in order to register the hologramx ',y 'when the object lies inthe x-y plane. Forthe reconstruction ofthe information ofthe object wave,phase-shifting digital holography includes two steps:(1) getting objectwave on hologram plane, and (2) reconstructing original object wave.2.1 Getting information of object wave on hologram plateDoing phase shifting N-1 times and capturing N holograms. Supposing the interferogram after k- 1 times phase-shifting is]),(cos[),(),(),,(k k b a I δηξφηξηξδηξ-⋅+= （1） Phase detection can apply two kinds of algorithms:synchronous phase detection algorithms [9]and the least squares iterative algorithm [10]. The four-step algorithm in synchronous phase detection algorithm is in common use. The calculation equation is)2/3,,(),,()]2/,,()0,,([2/1),(πηξπηξπηξηξηξiI I iI I E --+=2.2 Reconstructing original object wave by reverse-transform algorithmObject wave from the original object spreads front.The processing has exact and clear description and expression in physics and mathematics. By phase-shifting technique, we have obtained information of the object wave spreading to a certain distance from the original object. Therefore, in order to get the information of the object wave at its initial spreading position, what we need to do is a reverse work.Fig.1 Geometric coordinate of digital holographyexact registering distance.The focusing functions normally applied can be divided into four types: gray and gradient function, frequency-domain function, informatics function and statistics function. Gray evaluation function is easy to calculate and also robust. It can satisfy the demand of common focusing precision. We apply the intensity sum of reconstruction image as the evaluation function:min ),(11==∑∑==M k Nl l k SThe calculation is described in Fig.2. The position occurring the turning point correspondes to the best registration distanced, also equals to the reconstructing distance d '.It should be indicated that if we only need to reconstruct the phase map of the object wave, the registration distance substituted into the calculation equation is permitted having a departure from its true value.4 Spatial resolution of digital holography4.1 Affecting factors of the spatial resolution of digital holographyIt should be considered in three respects: (1) sizes of the object and the registering material, and the direction of the reference beam, (2) resolution of the registering material, and (3) diffraction limitation.For pointx2on the object shown in Fig.3, the limits of spatial frequency are λξθλθθ⎥⎦⎤⎢⎣⎡⎪⎪⎭⎫ ⎝⎛-'-=-=-0211maxmax tan sin sin sin sin z x f R R Fig.2 Determining reconstructing distanceλξθλθθ⎥⎦⎤⎢⎣⎡⎪⎪⎭⎫ ⎝⎛-'-=-=-0211minmin tan sin sin sin sin z x f R R Frequency range isλξξ⎥⎦⎤⎢⎣⎡⎪⎪⎭⎫ ⎝⎛-'-⎥⎦⎤⎢⎣⎡⎪⎪⎭⎫ ⎝⎛-=∆--02110211tan sin tan sin z x z x f so the range is unrelated to the reference beam.Considering the resolution of registering material in order to satisfy the sampling theory, phase difference between adjacent points on the recording plate should be less than π, namely resolution of the registration material.c f f f =∆η21)(min max 4.2 Expanding the spatial resolution of reconstruction imageExpanding the spatial resolution can be realized at least in three ways: (1) Reducing the registration distance z 0 can improve the reconstruction resolution, but it goes with reduction of the reconstruction area at the same ratio.Therefore, this method has its limitation. (2) Increasing the resolution and the imaging size of CCD with expensive price. (3) Applying image-synthesizing technique [11]CCD captures a few of images between which there is small displacement (usually a fraction of the pixel size) vertical to the CCD plane, shown in Fig.4(Schematic of vertical moving is the same).This method has two disadvantages. First, it is unsuitable for dynamic testing and can only be applied in the static image reconstruction. Second, because the pixel size is small (usually 5μm to 10μm) and the displacement should a fraction of this size (for example 2μm), it needs a moving table with high resolution and precision. Also it needs high stability in whole testing.In general, improvement of the spatial resolution of digital reconstruction isFig.3 Relationship between object and CCDstill a big problem for the application of digital holography.Fig.4 Image capturing by moving CCD along horizontal direction5 Testing resultsFig.5 is the photo of the testing system. The paper does testing on two coins. The pixel size of the CCD is 4.65μm and there are 1 392×1 040 pixels. The firstis one Yuan coin of RMB (525 mm) used for image reconstruction by phase-shifting digital holography. The second is one Jiao coin of RMB (520 mm) for the testing of deformation measurement also by phase-shifting digital holography.Fig.5 Photo of the testing system5.1 Result of image reconstructionThe dimension of the one Yuancoin is 25 mm. The registrationdistance measured by ruler isabout 385mm. We capture ourphase-shifting holograms andreconstruct the image byphase-shifting digital holography.Fig.6 is the reconstructed image.Fig.7 is the curve of the auto-focusfunction, from which we determine the real registration distance 370 mm. We can also change the controlling precision, for example 5mm, 0.1 mm,etc., to get more course or precision reconstruction position.Fig.6 Reconstructed image Fig.7 Auto-focus function5.2 Deformation measurementIn digital holography, the method of measuring deformation measurement differs from the traditional holography. It gets object wave before and after deformation and then subtract their phases to obtain the deformation. The study tested effect of heating deformation on the coin of one Jiao. The results are shown in Fig.8, Where (a) is the interferential signal of the object waves before and after deformation, and (b) is the wrapped phase difference.Fig.8 Heating deformation results5.3 Improving the spatial resolutionFor the tested coin, we applied four sub-low-resolution holograms to reconstruct the high-resolution by the image-synthesizing technique. Fig.9 (a) is the reconstructed image by one low-resolution hologram, and (b) is the high-resolution image reconstructed from four low-resolution holograms.Fig.9 Comparing between the low and high resolution reconstructed image6 SummaryDigital holography can obtain phase and amplitude of the object wave at the same time. Compared to other techniques is a big advantage. Phase-shifting digital holography can realize image reconstruction and deformation with less noise. But it is unsuitable for dynamic testing. Applying the intensity sum of the reconstruction image as the auto-focusing function to evaluate the registering distance is easy, and computation is fast. Its precision is also sufficient. The image-synthesizing technique can improve spatial resolution of digital holography, but its static characteristic reduces its practicability. The limited dimension and too big pixel size are still the main obstacles for widely application of digital holography.外文文献译文：标题：图像重建中的相移数字全息摘要：相移数字全息术被用来研究研究艺术品的内部缺陷。
电子信息工程专业毕业论文中英文资料外文翻译文献
毕业论文毕业论文中英文对照翻译中英文对照翻译院（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.The purpose that design this system is transmit customer’s operation information with infrared rays for transmit media, then demodulate original signal with receive circuit. It use coding chip to modulate signal and use decoding chip to demodulate signal. The coding chip is PT2262 and decoding chip is PT2272. Both chips are made in Taiwan. Main work principle is that we provide to input the information for the PT2262 with coding keyboard. The input information was coded by PT2262 and loading to high frequent load wave whose frequent is 38 kHz, then modulate infrared transmit dioxide and radiate space outside when it attian enough power. The receive circuit receive the signal and demodulate original information. The original signal was decoded by PT2272, so as to drive some circuit to accomplish customer’s operation demand.Keywords:Infrare dray；Code；Decoding；LM386；Redoutside transceiver1 Introduction1.1 research the background and significanceInfrared Data Communication Technology is the world wide use of a wireless connection technology, by the many hardware and software platforms supported. Is a data through electrical pulses and infrared optical pulse switch between the wireless data transceiver technology.Infrared transceiver products with low cost, small, fast transmission rate, the point-to-point transmission security, not subject to electromagnetic interference and other characteristics that can be achieved between the different products, rapid, convenient and safe exchange and transmission, In short distance wireless transmission have a very distinct advantage.Infrared transceiver products in the portable product of a great role. At present, the world's 150 million piece of equipment used infrared technology in electronic products and industrial equipment. medical equipment and other fields widely used. For example, 95% of the notebook computers on the installation of infrared transceiver interface the majority of the cell phone is also the allocation of infrared transceiver interface. With the exchange of quantitative data, infrared data communications will enable cell phone data transmission more convenient. With infrared data transmission technology matures, perfect, low costs, Infrared Transceiver in short distance communications will be more widely applied.This chapter first describes the infrared transceiver IC design issues to the background and significance. then briefed the infrared data communications technology features and applications, and infrared transceiver product characteristics, domestic and international situation and development trend of the last under infrared remote transceiver system in practical application to establish a task of design orientation.1.2 Infrared Remote ControlTransceiver SystemInfrared remote control system is divided into single-channel and multi-channel remote control. Only a command signal transmission channel, called single-channel remote control system; with more than two instructions signal transmission channel known as a multi-channel remote control system. Relatively simple single-channel remote control, in general, only a launcher directive Key receivers and only one circuit implementation. While in the receiving circuit to add more stable memory circuits that can be activated commands to launch a number of key, so that the receiver circuit multistable memory circuit repeatedly to change the state, to realize many of the functional control, But such a state of change is the order. If we are to achieve an arbitrary control, resort to the use of multi-channel remote control system. Multi-channel remote control can be realized by the object of arbitrary multi-function remote control. As for the choice of several routes and what control methods, according to the actual situation (such as object, operational requirements and cost accounting, etc.) to decide. General infrared remote transceiver system by infrared remote control transmitter signal coding, infrared remote control signal receivers and decoders (or decoder chip MCU) and the external circuit consisting of three parts. Signal transmitter remote control code used to generate pulses of infrared emission-driven output infrared remote control signal, receiver completion of the remote control signal amplification and detection, plastic and demodulation encoding pulse. Infrared remote control coded pulse is going to obtain a continuous serial binary code, and for most of the infrared transceiver system, This serial code as micro-controller of the remote control input signals from the internal CPU completion of the remote control instruction decoder, on the other infrared remote control transceivers, the designers of electronic products, The internal micro-controller of the remote control decoder directive is not accessible.Therefore, people are using infrared encoder / decoder chip and microcontroller developed various generic infrared remote transceiver system, In various equipment infrared signals between the transceiver.Remote transceiver system generally transmitters and receivers is composed of two parts. Launchers from the general direction keys, coded instructions circuit modulation circuit, driving circuit, firing circuit of several parts. When pressed a key, the directive coding circuit, in the corresponding instructions encoded signal, the encoder signal to the carrier modulation, Driven by the power amplifier circuit after circuit fired from the field after firing instructions coded modulation signals. General receiver by the receiving circuit, the amplifier circuit, demodulation circuits, instruction decoder circuit, driving circuit, circuit implementation of several parts. Receiving Circuit will launch vehicles have been coded modulation signal receiving instructions from, and to enlarge evacuation demodulation circuit. Demodulation circuit will have the coding modulation signal demodulation, namely, reduction of signal coding. The instruction decoder to the encoder signal decoding, Driven by the final circuit to drive the implementation of various instructions circuit to control the operation.1.3 infrared remote control transceiver product profiles 1.3.1 infrared remote control transceiver product structure and typeCurrently infrared transceiver in accordance with the mode of transmission rate and can be divided into four categories : Serial mode, the highest rate of 115.2 Kbps; medium-speed model : the highest rate of 0.567 Mbps and 1.152Mbps; High-speed mode : The maximum rate of 16 Mbps.Also according to the size chip power consumption can be divided into low-power consumption and standard two categories, low-power type normally used 3 V power supply, transmission distance closer to about 0 - 30cm, which is commonly used standard 5V power supply, transmission distance away at least 1mabove.1.3.2 infrared remote control transmitters of the status quo at home and abroadInfrared communication technology in the development stage and there are several infrared communication standards, between different standards for infrared equipment can not infrared communication. To have all the infrared equipment to interoperability in 1993 by more than 20 large manufacturers initiated the establishment of an Infrared Data Association (IRDA) unified the infrared communication standards , which is currently widely used in infrared data communication protocols and standards, also known as the IRDA standard.Since 1993 IRDA since the establishment of the Infrared Data Association members have developed to more than 150. IRDA standards of the industry has been widely recognized and supported. Has been developed with the infrared communications equipment have been as many as 100 species. IR module, installed capacity has reached 150 million sets. Although there is also a short distance wireless Bluetooth technology, But in infrared communication technology low cost and broad compatibility advantages, Infrared data communication in the future will still be a very long time inherent short-range wireless data communications fields play an important role.1.3.3 Infrared Transceiver product development trendIn various infrared transceiver products, although the transmission rate, transmission distance and other characteristics, But infrared transceiver products has been towards improving the transmission rate, increase the transmission distance and lower power consumption, expanding launch reception angle of development. In particular, as the technology development and maturity, the means of transmission is moving in the direction of point-to-multipoint. Therefore infrared remote control transceiver products have broader prospects for development.2 Infrared communication of knowledge2.1 infrared ray foundation knowledge2.1.1 infrared outlinedInfrared is actually a kind of electromagnetic wave. From the analysis of various natural component of the electromagnetic wave reflected spectrum is :-ray, x-ray, ultraviolet, visible, infrared, microwave and radio wave. From the viewpoint of form, and they did not seem to, but if the wavelength in descending order, and we will find him all the only visible light spectrum of the entire 0.38 µm - 0.76µm so long little area, and adjacent to the visible light and infrared (including the far infrared, mid-infrared and near infrared foreign) accounts for the spectrum of 0.76 µm - 1000µm of a major. Which micron wavelength range also includes UV, visible, near infrared, mid-infrared and far-infrared, microwave.From the above analysis shows that infrared is a very rich spectrum resources, it currently has in production, life, military, medical, and other aspects have been widely used, such as infrared heating, medical infrared, infrared communication, infrared camera, infrared remote control, and so on. Infrared remote control is the many applications of infrared part of the current household appliances widely used in TV remote control, VCR remote control, VCD remote control, high-fidelity audio remote control, are used infra-red remote control, It allows the control of these appliances have become very easy.2.1.2 infrared propertiesInfrared lies between visible light and microwave a wave, it is with certain clinical characteristics of the wave. In the near-infrared, visible light and its adjacent, it is visible in certain characteristics, such as straight-line transmission, reflection, refraction, scattering, diffraction, can be certainobjects and can be absorbed through the lens of their focusing. In the far-infrared region, owing to its neighboring microwave, it has some characteristics of microwave, If a strong penetrating power and can run through some opaque substances. Since in any object, natural profession, regardless of whether its own luminescence (referring to visible light), as long as the temperature is above absolute zero (-273 ° C), moment will be kept around to infrared radiation. Only higher temperature of objects strong infrared radiation, low-temperature objects infrared radiation weaker. Therefore infrared feature is the greatest common in nature, it is called thermal radiation called thermal radiation. Infrared cameras, infrared night market pyroelectric infrared detectors and some other missiles aiming at is the use of this characteristic of infrared work.Infrared and visible light compared to another characteristic of a variety of colors. As the longest wavelength of visible light is a wavelength of the shortest times (780 nm-380 nm), So is called an octave. And infrared wavelength is the longest shortest wavelength of a times, and the longest wavelength infrared is the shortest wavelength of 10 times, that is, 10 octave. Therefore, if visible light can be expressed as seven colors, infrared may performance 70 colors, showing the rich colors. Infrared smoke through the good performance, which is also one of its features.Because not visible to the infrared, it has little effect on the environment. By the wave infrared rays than the long wavelength radio waves, infrared remote control will not affect the nearby radio equipment. Another wavelength of less than 1.5µm near infrared light, transparent atmosphere in the visible light transmission characteristics much better than, because it close to the visible edge of the red light, linear transmission, reflection, refraction and absorption material and the physical characteristics very similar to visible light. Therefore, it can be used with similar visible focusing lens and other opticaldevices. Because infrared remote control is not as remote as the radio through the barrier to control the object's ability to control, so in the design of household appliances infra-red remote control, wireless remote control as unnecessary, each set (transmitters and receivers) have different frequency or remote coding (Otherwise, wall will control or interference with neighbors household appliances), all similar products in the infrared remote control, The same can control the frequency or coding, and no remote control signal "drop." This universal infrared remote control provides a great convenience. Infrared to visible light, is very subtle and confidentiality, therefore, the security, Alert and other security devices have been widely used. Infrared remote control is simple in structure and easy, low-cost, anti-interference capability, high reliability are a number of advantages, is a close-up remote control, especially in indoor remote control optimized manner.2.1.3 infrared diode characteristicsInfrared is not visible, people here are not aware of. Electronic technology is used infrared light emitting diode (also known as the IR emission diode) to generate infrared. Infrared remote control transceiver is using near-infrared transmission control instructions 0.76µm wavelength of ~ 1. 5µm. Near-infrared remote control as a light source, because there infrared light emitting diodes and infrared receiving device (photodiode. Transistor and PV) and the luminescence peak wavelength of light by the general 0.8µm ~ 0. 94µm. in the near-infrared band, both of the spectrum is the coincidence to a good match, access to higher transmission efficiency and higher reliability. Commonly used infrared diode, and its shape is similar LED light emitting diodes, Its basic circuit shown in figure 2 -2. The triode plans for the switch, when the base added a driving signal, Transistor saturated conduction infrared LED D is also Wizard Link, issued infrared (near infrared about 0.93 µm). D.The pressure drop of about 1.4 V and the current general for 10-20mA. To adapt to the working voltage of the D loop resistance often as a series of infrared diode current limit resistance.When the circuit diagram of the infrared emission control corresponding to the controlled device, the control of the distance and D is proportional to the transmitting power. In order to increase the distance of infrared control, infrared diode D should work on the pulse state that work is the lifeblood of current. Because pulse light (optical modulation) the effective transmission distance and pulse is proportional to the peak current, only maximize peak current Ip, will increase the infrared distance. Ip increase is a way to reduce the pulse duty cycle, that is compressed pulse width τsome TV infrared remote control, its infrared luminescence of the pulse duty cycle of about 1/4-1/3; Some electrical products infrared remote control, its duty cycle of 1 / 10. Decreasing pulse duty cycle also enable low-power infrared LED distance of the greatly increased. Common infrared light emitting diodes, power is divided into small power (1 mW - 10mW). Chinese power (20mW - 50mW) and power (50mW - 100mW more) three categories. Use different power infrared LED, the allocation should be driven by the corresponding power control. Figure 2 -2 by the reflected infrared light-emitting diodes to make produce optical modulation, Drivers only need to add the control of a certain frequency pulse voltage.Infrared transmitter and receiver in the way the two kinds of straight, and the second is reflective. Luminescence pointed straight pipe and tube receiver placed in a relatively controlled and fired on the two ends, a certain distance away from the middle; Reflective means luminescent tube and pipe parallel with the receiving peacetime, without always receiving tube light, luminescence only in possession of the infrared light reflected fromencountered, the receiving tube received from the reflected infrared before work.2.2 infrared communication basic tenets2.2.1 infrared communication PrincipleCommunication is the use of infrared wavelength of 900 nm-infrared waves from 1000 to serve as an information carrier, through infrared technology between the two close communication and confidentiality of information transmitted. Infrared communication system structure include : part launcher, channel, the receiver part.Launcher source letter issued after the binary signal from the high-frequency modulated infrared LED sent, receiving device regard the reception of high-frequency signals from the infrared receiver tube after receiving further demodulation photoelectric conversion of the original information of a mass communication lose way. Afterwards the former Information received after receiving part of the drive circuit connected to the expected completion of the various functions. To which the modulation coding style pulse width modulation (by changing the pulse width modulated signal PWM) and pulse modulation time (through change the pulse train interval time between the modulation signal PPM) two.2.2.2 infrared communication system elements(1) Launches : Currently there is a infrared wireless digital communications system sources of information including voice, data, images. Its methods of work for the launch of the receiver can be divided into different layout LOS way (Light-of-Sight , intracardiac way), diffuse (diffuse) mode. LOS way directional, it has good channel characteristics such advantages, but the existence of a "shadow" effect. difficult to achieve roaming function. Roaming means the main features of non-directional, and easy to implementroaming function, but its channel quality is better sometimes LOS way. Transmission of signals required for a few of (the sampling was quantified), the general need for baseband modulation, transmission, modulation, sometimes signal source coding, the above-driven signals from photoelectric converter complete optical signal transmission. Infrared wireless digital communications system and its scope of work-for-fired power distribution, the quality of the communication. While using various methods to improve optical transmitter power, the other using spatial diversity, holographic films and so on so diffuse light for the launch of space optical power evenly distributed.(2) Channel : infrared wireless digital communication channel refers to the transmitters and receivers in the space between. Due to natural light and artificial light sources such as light signals in the context of intervention, and the source - Electrical Equipment, The optical noise and disturbances, infrared wireless digital communications in some occasions, poor quality, At this point needed to channel coding. Infrared wireless communication system, the optical signal reflection, light scattering and background noise and interference effects, Infrared wireless digital channel presence multi-path interference and noise, This is to improve the quality and access for high-speed applications should be addressed. Infrared wireless digital communication channel often used by the major optical components, optical filter, condenser, their role is : plastic, filter, depending on the field transformation, the band division, the lens can be used as launch-ray focusing, the use of optical filters filter out stray light, the use of optical lenses to expand the field of view receiver, able to make use of optical components for the link frequency division multiplexing, etc.. Infrared wireless communication channel optical noise : the natural noise (sunlight) and anthropogenic interference (fluorescent lighting). can be modulated by the transmission technology such as filters and adding to be addressed.(3) receivers : Channel optical signal from the optical receiver partially photoelectric conversion, In order to remove noise and intersymbol interference and other functions. Infrared wireless digital communications system receiver include optical receiver parts and follow-up sampling, filtering, judgment, quantity, balanced and decoding part. Infrared wireless optical receiver often used amplifier, and called for large-bandwidth, high gain, low noise and low noise, frequency response and channel impulse response matched. To be suppressed by low-frequency noise and human disturbance needs a band-pass filter. To obtain large optical receiver scope and instantaneous field of view, often using spherical optical lens.2.2.3 infrared communications featureWireless communications are a lot of ways, some using infrared communication with the following characteristics :• The high frequency, wave length, and fired the energy concentrated space propagation attenuation coefficient can ensure the effective signal transmission;• infrared is the invisible light, strong confidentiality and use it as an information carrier. device when there is no visual pollution, it does no harm to the human body;• dissemination without limitation, and there is no question of frequency interference with radio-wave pattern, not on the spectrum resources to the relevant authorities for the application and registration, easy to implement;• has a good point, when the transmission equipment and infrared receiver ports line up straight, deviation of not more than about 15 degrees when infrared devices running the best effect;• through infrared or not bypassed and objects, data transmission, optical path can not be blocked;• currently produce and receive infrared signals in the technology is relatively mature, components small size, low cost production of simple, easy to produce and modulation advantages.2.3 infrared communication code based on the knowledgeUsually, infrared remote control transmitters will signal (pulse binary code) modulation at 38 KHz carrier, After buffer amplified sent to the infrared light-emitting diodes, infrared signals into firing away. Pulse binary code in a variety of formats. One of the most commonly used code is PWM (pulse width modulation code) and the PPM code (Pulse Code Modulation). The former said in a pulse width, pulse indicated 0. The latter pulse width, but the width of code-not the same, the codes represent a bit - and the digits represent narrow 0.Remote coding pulse signal (PPM code as an example) are usually guided by the code, the system code, the anti-code system, a feature code, functional anti-code signal components. Guide the code name for the initial code, by the width of 9 ms and the margin width of 4.5 ms to the low-level components (different remote control systems in the low-level high width of a certain distinction), remote coding used to mark the beginning of pulsed signals. System identification code is also called code, which used to indicate the type of remote control system, in order to distinguish other remote-control system, prevent the remote control system malfunction. Functional code is also called scripts, which represents the corresponding control functions, Receiver of the micro-controller functions under the numerical code to complete the various functions operating. Anti-code system and function codes are anti-system code and the functional code against code Anti-code can be joined to the receiver synchronization transmission process leads to errors. In order to improve performance and reduce interference power consumption, The remote control will be coded pulse frequency of 38 KHz (for the cycle of 26.3 ms) of the carrier signal pulse reshuffle system (PAM), and then sentto the buffer amplified infrared LED, the remote control signal transmitter away.Address code and data codes are composed of different pulse width expressed that the two narrow pulse "0"; 2 pulse width "1"; a narrow pulse width and pulse expressed an "F" is the code addresses "vacant."Is the first part of a group a group of code, each code synchronization between separated. The plan is to enlarge the second half of a group code : a code from 12 AD (the address code plus data code For example, eight address code plus four data code), each with two AD-Pulse's : Pulse said the two "0"; 2 pulse width "1"; a narrow pulse width and pulse expressed an "F" is the code addresses "vacant."Realize fired at each fired at least four groups code, PT2272 only twice in a row to detect the same address code plus data code data will be the code "1" is driven The data should be output to drive margin and VT terminal for synchronous serial.红外遥控系统摘 要红外数据通信技术是目前在世界范围内被广泛使用的一种无线连接技术，被众多的硬件和软件平台所支持。
光学信息工程外文翻译
Photographic ObjectivesIn this section, we will outline the basic design principles of the photographicobjective, and for this purpose we will classify objectivesaccording to their relationship to, or derivation from, a few major categories:(a) meniscus types, (b) Cooke triplet types, (c) Petzval types,and (d) telephoto types. These categories are quite arbitrary and are chosen for their value as illustrations of design features rather than any historic or generic implications.In this category, we include those objectiveswhich derive their field correction primarily from the use of a thick meniscus. As mentioned in Secs. 12.1 and 12.2, a thick-meniscus element has a greatly reduced inward Petzval curvature in comparisonwith a biconvex element of the same power; indeed, the Petzval sum can be overcorrected if the thickness is made great enough. The simplest example of this type of lens is the Goerz Hypergon (Fig. 12.4)which consists of two symmetrical menisci. Because the convex and fact that the surfaces are nearly concentric about the stop enablesthe lens to cover an extremely wide (135°) field, although at a very low aperture (f/30).To obtain an increased aperture, it is necessary to correct the spherical and chromatic aberrations. This can be accomplished by the additionof negative flint elements, as in the Topogon lens, Fig. 13.10. Note that the construction of this lens is also very nearly concentric about the stop; lenses of this type cover total fields of 75° to 90° at speeds off/6.3 to f/11.To obtain an increased aperture, it is necessary to correct the sphericaland chromatic aberrations. This can be accomplished by the additionof negative flint elements, as in the Topogon lens, Fig. 13.10. Note that the construction of this lens is also very nearly concentric about the stop; lenses of this type cover total fields of 75° to 90° at speeds off/6.3 to f/11. symmetry helps to control the coma and distortion. Lenses of theProtar type cover total fields of 60° to 90° at speeds of f/8 to f/18.A few years later, Rudolph and von Hoegh (Goerz), working independently, combined the two components of the Protar into a singlecemented component, which contained both the required dispersingand collective cemented surfaces. The Goerz Dagor is shown in Fig. 13.12, and is composed of a symmetrical pair of cemented triplets. Each half of such a lens can be designed to be corrected independentlyso that photographers were able to remove the front component toget two different focal lengths. A great variety of designs based on this principle were produced around the turn of the century, using three, four, and even five cemented elements in each component, although very little was gained from the added elements. Protars and Dagors are still used for wide-angle photography because of the fine definition obtained over a wide field, especially when used at a reduced aperture. See Fig. 14.14 for an example of a Dagor design.The additional degree of freedom gained by breaking the contact of the inside crowns of the Dagor construction proved to be of more value than additional elements. Lenses of this type (Fig. 13.13) are probably the best of the wide-angle meniscus systems and cover fields upto 70° total at speeds of f/5.6 (or faster for smaller fields). The Meyer Plasmat, the Ross W. A. Express, and the Zeiss Orthometar are of this construction, and recently excellent 1:1 copy lenses (symmetrical) have been designed for photocopy machines. Note that the broken contact allows the inner crown to be made of a higher-index glass.The design of the thick-meniscus anastigmats is a complex undertaking because of the close interrelationship of all the variables. In general the exterior shape and thickness are chosen to control the Petzval sum and power, and the distance from the stop can be used to adjust the astigmatism. However, the adjustment of element powersto correct chromatic inevitably upsets the balance, as does the bending of the entire meniscus to correct spherical. What is necessary is one simultaneous solution for the relative powers, thicknesses, bendings, and spacings; an approach of the type described in Secs. 12.7 and 12.8 for the simultaneous solution of the third-order aberrations is ideally suited to this problem, and the automatic computer design programs make easy work of it.suited to this problem, and the automatic computer design programs make easy work of it.The double-Gauss (Biotar) (Fig. 13.14) and the Sonnar types (Fig.13.15) of objectives both make use of the thick-meniscus principle, although they differ from the preceding meniscus types in that they are used at larger apertures and smaller fields. The Biotar objective in its basic form consists of two thick negative-meniscus inner doublets and two single positive outer elements as shown in Fig. 13.14. This is an exceedingly powerful design form, and many high-performancelenses are modifications or elaborations of this type. If the vertex length is made short and the elements are strongly curved about the central stop, fairly wide fields may be covered. Conversely, a long system with flatter curves will cover a narrow field at high aperture.Common elaborations of the Biotar format include compounding the outer elements into doublets or triplets or converting the meniscusdoublets into triplets. Frequently the outer elements are split (after shifting some power from the inner crowns) in order to increase the speed. Some recent designs have advantageously broken the contact at the cemented surface, especially in the front meniscus.As indicated above, the double-Gauss (Biotar) is an extremely powerful and versatile design form. It is the basis of most normal focal length 35-mm camera lenses and is found in many applications where extremely high performance is required of a lens. It can be made into a wide-angle lens or can be modified to work at speeds in excess of f/1.0 with equal facility.。
信息与计算科学中英文对照外文翻译文献
中英文对照外文翻译文献(文档含英文原文和中文翻译)【Abstract】Under the network environment the library information resource altogether constructs sharing is refers to all levels of each kind of library basis user to the social information demand, through network use computer, correspondence, electron, multimedia and so on advanced information technology, the high idealization carries on the synthesis cooperation development and the use activity to various collections information resource and the network resources . The market economy swift and violent development, the networking unceasing renewal, the information age arrival, had decided the future library trend of development will be implements the information resource altogether to construct sharing, already achieved the social mutual recognition about this point.This is because:libraries implement the information resource altogether to construct sharing are solve the knowledge information explosion and the collection strength insufficient this contradictory important way..【Key Words】Network; libraries implement: information: construction；work environment the libraryUnder the network environment the library information resource altogether constructs sharing is refers to all levels of each kind of library basis user to the social information demand, through network use computer, correspondence, electron, multimedia and so on advanced information technology, the high idealization carries on the synthesis cooperation development and the use activity to various collections information resource and the network resources.1、 information resource altogether will construct sharing is the future library development and the use information resource way that must be taken.The market economy swift and violent development, the networking unceasing renewal, the information age arrival, had decided the future library trend of development will be implements the information resource altogether to construct sharing, already achieved the social mutual recognition about this point.This is because: 。
光通信技术外文翻译
外文文献阅读及翻译译文及原稿译文题目以太网无源光网络原稿题目 Passive optical network based on Ethernet 姓名吴腾学号 31202130班级通信1204以太网无源光网络格伦·克雷默北京邮电大学出版社2007以太网无源光网络（Ethernet Passive Optical Network ， EPON）是一种新型的光纤接入网技术，它采用点到多点结构、无源光纤传输，在以太网之上提供多种业务。
它在物理层采用了PON技术，在链路层使用以太网协议，利用PON的拓扑结构实现了以太网的接入。
因此，它综合了PON 技术和以太网技术的优点：低成本；高带宽；扩展性强，灵活快速的服务重组；与现有以太网的兼容性；方便的管理等等。
由于EPON的众多优点，它越来越受到人们的青睐，即将成为宽带接入网一种最有效的通信方法。
为了保证EPON网络能够稳定、高效、准确的运行，为EPON提供一个有效的网络管理系统显得尤为重要。
在网络管理领域，随着基于TCP/IP体系的网络管理技术的不断发展，SNMP已经成为事实上的标准。
基于SNMP的EPON网络管理系统是指采用SNMP管理协议框架，对EPONSNMP的介绍SNMP（简单网络管理协议）是一种基于TCP/IP的网络管理协议，它使用UDP作为传输层协议，能管理支持代理进程的网络设备。
SNMP主要包括SMI（管理信息结构）、MIB（管理信息库）和SNMP协议几部分。
SMI 给出了管理对象定义的一般框架。
MIB是设备所维护的全部被管理对象的结构集合。
SNMP协议包括SNMP操作、SNMP信息的格式以及如何在应用程序和设备SNMP采用代理/管理站模型进行网络管理。
SNMP有5种消息类型，分别为Get-Request、Get-Response、Get-Next-Request、Set-Request和Trap。
代理和管理站之间通过这几种消息报文进行相互通信，以获取网络设备的各种信息，从而控制网络设备的正常运行。
光电信息工程外文翻译文献
光电信息工程外文翻译文献(文档含中英文对照即英文原文和中文翻译)译文：气体温度通过PECVD沉积对Si：H薄膜的结构和光电性能的影响摘要气体温度的影响（TG）在等离子体增强化学气相沉积法（PECVD）生长的薄膜的结构和光电特性：H薄膜已使用多种表征技术研究。
气体的温度被确定为制备工艺的优化、结构和光电薄膜的性能改进的一个重要参数。
薄膜的结构性能进行了研究使用原子力显微镜（AFM），傅立叶变换红外光谱（FTIR），拉曼光谱，和电子自旋共振（ESR）。
此外，光谱椭偏仪（SE），在紫外线–可见光区域的光传输的测量和电气测量被用来研究的薄膜的光学和电学性能。
它被发现在Tg的变化可以修改的表面粗糙度，非晶网络秩序，氢键模式和薄膜的密度，并最终提高光学和电学性能。
1.介绍等离子体增强化学气相沉积法（PECVD）是氢化非晶硅薄膜制备一种技术，具有广泛的实际应用的重要材料。
它是用于太阳能电池生产，在夜视系统红外探测器，和薄膜晶体管的平板显示装置。
所有这些应用都是基于其良好的电气和光学特性以及与半导体技术兼容。
然而，根据a-Si的性质，PECVD制备H薄膜需要敏感的沉积条件，如衬底温度，功率密度，气体流量和压力。
许多努力已经花在制备高品质的薄膜具有较低的缺陷密度和较高的结构稳定性的H薄膜。
众所周知，衬底温度的强烈影响的自由基扩散的生长表面上，从而导致这些自由基更容易定位在最佳生长区。
因此，衬底温度一直是研究最多的沉积参数。
至于温度参数在PECVD工艺而言，除了衬底温度，气体温度（Tg）美联储在PECVD反应室在辉光放电是定制的a-Si的性能参数：H薄膜的新工艺。
事实上，TG PECVD系统的变化可以影响等离子体的能量在辉光放电，并最终改变了薄膜的性能。
根据马丁吕，当薄膜制作接近前后颗粒的形成机制在a-Si∶H薄膜，薄膜性能对TG的相关性比衬底温度更为显著。
然而，大多数的研究到目前为止只集中在衬底温度的影响。
在我们以前的研究中，我们报道的气体温度对磷的结构演化的影响掺杂的a-Si∶H薄膜的拉曼光谱。
光信息科学与技术
光信息科学与技术光信息科学与技术是一门运用光电子学原理和技术，研究光信号的传输、处理和应用的学科。
它涉及到光学理论、电子技术、光学器件与系统技术等多个领域，与现代信息技术密切相关，是信息科技发展的重要支撑。
光信息科学与技术的起源可以追溯到20世纪50年代，当时光子学的出现开启了这一领域的研究。
在光信息传输中，一个重要的挑战是如何将光信号稳定地传输到远距离的位置。
在20世纪六七十年代，光导纤维的发明解决了这个问题，因此，将光学纤维用于信息传输成为光信息传输的一个主要方法。
随后的几十年内，光信息科学与技术在各个领域和应用中得到了广泛应用。
如今，它逐渐成为了光电子学、通信、光学成像、医疗等多个领域不可或缺的一部分。
在数字通信技术中，光信息传输已经取代了原有的传输方式，成为了主流。
在高速互联网、智能手机和网络游戏等领域，光信息传输的速度和可靠性为信息传递带来了更多的便利。
尽管光信息科学与技术在多个领域应用广泛，仍存在一些特定领域内的问题亟需要解决。
例如，在医学成像中，由于光的散射和吸收等问题，使得深度成像面临很大的挑战。
在安全通信领域，量子密钥分发技术近年来得到了广泛的研究和应用，但其实用性仍然存在一些技术瓶颈。
因此，进一步发展光信息科学与技术和光通信技术仍然具有重要意义。
未来的发展方向主要包括：在光通信技术中进一步降低能量损耗，提高信号传输速度；在光学成像和诊断技术方面研究新的解决方案；探索基于光的新型处理器和计算机，以推动信息处理技术前进。
总之，在信息科技发展中，光信息科学与技术将继续发挥着不可或缺的作用，为人类带来更加便捷、高效的生活方式。
毕业设计论文 外文文献翻译 光信息科学与技术 光电目标位置和速度测量系统 中英文对照
Electro-optical target system for position and speed measurementAbstractThis paper introduces an electro-optical target system(EOTS) covering the speed range from subsonic to supersonic. This microcomputer-based system has a novel structure and shows the capability of precisely detecting the position as well as the velocity of small caliber projectiles in real time. A prototype EOTS whose target area is 1m2 has been constructed and tested. A speed accuracy of better than 0.3% was achieved. A position accuracy, mainly dependent on the spacing between photodiodes in EOTS, of better than 1mm on a target area of 1m2was also accomplished.Keywords: External ballistics, No contact measurement, Electro-optical techniques, Position measurement, Speed measurement1 IntroductionThe speed and position measurements of projectiles are two important items in ballistic research. To determine these parameters precisely one needs an accurate measuring system. A conventional method, namely the hanging up(and taking down) of target discs[l], though accurate in position measuring, is time consuming. A shot-position indicator(SPI), described in Reference 2, can measure the position of a high speed projectile by acoustic measurement. However, the SPI does not provide the speed information; neither does the conventional method. Besides, the SPI is used within the limits of supersonic projectiles.To measure the speed and position of projectiles rapidly and simultaneously, different electro-optical based systems have been proposed 3-5]. These systems have the ability to cover the speed range from subsonic to supersonic. One system, called the target measurement system(TMS)[3], uses vertical and horizontal banks of light sources to form two perpendicular light grids that construct the target area. Another system, called the electro-optical projectile analyzer[4], uses the same principle as TMS, but simplifies light sources with fiber optics bundles and a single light source in each light grid. The other system, called the electronic yaw screen(EYS)[5], uses a solid state laser that is collimated and directed to a one-dimensional beam expander system to form a fan-shaped light screen. This light screen then is reflected by a mirror to construct a portion of the target area. The light screen is more precise than the light grid because there is no dead zone in the target area as with the light grid system.From the aspect of speed and position measurement, we take advantage of the above systems and propose a novel system; the electro-optical target system(EOTS)[6]. We use a cylindrical mirror that reflects the incident laser beam into a 90º fan-shaped light screen. Two such light screens construct a two-dimensional positioning system. We even propose a bent cylindrical mirror to generate a 90º light screen with a few degrees extended in a direction normal to the light screen to reduce the sensitivity to vibrations.A prototype EOTS, whose target area is 1m2 and measured speed range is from 50m/s to 1200m/s, has been constructed and tested. A speed range of up to 5000m/s can also be expected according to the simulation results from the electronic circuit using PSpice[7]. Finally, a nine-point testing result from a 0.38in. pistol is shown in this paper. The result shows that the standard deviation of position accuracy is less than 1mm.2 Basic principle of EOTSFig. 1 shows the optical configuration of EOTS. A laser beam from a He-Ne laser is directed onto a cylindrical mirror. The reflected laser beams create a fan-shaped light screen and are directed onto photodiodes that are neatly arranged into an L-shaped photodiode array. EOTS uses two laser sources, two cylindrical mirrors and two photodiode arrays, which are arranged on the opposite sides of the EOTS body to form two fan-shaped light screens. Each light screen is combined with its own signal processing circuit to construct an optical gate. Although there is a distance between the two parallel light screens, viewed from a distance point, these fan beams intersect in a region of space called the target area (Fig. 2). A projectile can be measured only if it travels through this target area.Fig. 1 Optical configuration of EOTSFig. 3 shows the shot position of the projectile is calculated. The target area, for the convenience of illustration, is a square of dimension D on each side. The number of photodiodes on the L-shaped photodiode array is 2N . Each photodiode is numbered in order, as shown in the figure. For illustration clarity, only the photodiode array and the cylindrical mirror of the first optical gate are shown. The projectile is considered to be incident normally to the first and to the second optical gate in sequence. When the projectile blocks the light screens, the respective photodiodes will be activated by the disturbance. In the first optical gate, the laser beam from the cylindrical mirror to each photodiode makes a unique angle with the y-axis. This angle is measured counter-clockwise from the axis. The angle with respect to a photodiode, numbered n, can be calculated as 12()()arctan ,1n n n N Nδ1-=≤≤ (1) and12()arctan ,12(2)N n N n N N n δ1=+≤≤-+ (2) If certain photodiodes, numbered from j to k , are activated by projectiles, then the shot-position angle δ1, is given by()()2j k δδδ111+= (3)Fig. 2 Intersections of the two light screens in the target area Similarly, the shot-position angle of the second optical gate δ2, measured clockwise from the minus y-axis, is decided. After the two angles have been measured, theFig. 3 Illustration of shot-position calculation shot position of the projectile is deduced in Cartesian coordinates as212tan tan tan D y δδδ=+ (4) and1tan z y δ= (5)If S is the distance between the two light screens, then the average speed v for the projectile passing through the distance S is given byS v T= (6) where T is the time interval for the projectile to pass through distance S .3 Configuration of EOTS3.1 Optical system of EOTSWe use a He-Ne laser directed onto a cylindrical mirror to create a light screen. The relation among the laser beam diameter d, the cylindrical mirror diameter w and the beam expanding angle φ is shown in Fig. 4. This relation can be calculated as2arcsind w φ=2 (7) To create a light screen of which φ equals 90º, the ratio of w to d is 2.8. Because the He-Ne laser beam has Gaussian distribution and each photodiode on the photodiode array has a different distance to the cylindrical mirror, the received laser power at each photodiode is not constant. This will influence the speed accuracy of EOTS (see Fig. 6 and Section 4.1).3.2 Analogue circuitryEOTS has 2N analogue channels in each of its two optical gates. Every analogue channel has the same structure. Each analogue channel contains a photodiode, a linear amplifier, a band-pass filter and a comparator. The linear amplifier amplifies the signal coming from the photodiode. The band-pass filter filters noises such asFig.4 Laser beam directs on a cylindrical mirrorbugs flying through the light screen and flicker of other light sources nearby. The comparator compares the output V0 , coming from the filter with a threshold voltage V TH. If V0is higher than V TH, then the comparator will activate a flip-flop (FF) to change the state.3.3 Digital circuitryFig.5 is the block diagram of the digital signal processing circuit. Input coming from the analogue channel is fed to a relative FF. When the projectile blocks the light screen of the first optical gate, the state-changed FF s will make the output of the NAND gate U1 change state. The U1 locks all FF s of the first optical gate to protect genuine projectile data from the influence of shock waves behind the projectile, and starts the counter U5 that operates at a clock frequency of 10MHz. As the projectile blocks the light screen of the second optical gate, the circuit of the second optical gate functions as the circuit of the first optical gate did, but stops the counter. Moreover, the NAND gate U2 passes an interrupt signal (INT) to the central processing unit (CPU) while U5 is being stopped. The CPU then recognizes the interrupt request, picks the projectile data up, and resets U5 and all FF s for the next shot, in sequence. In Fig. 5, the counter relates the time interval T in eqn. 6. Besides, every photodiode is assigned a specific FF and every FF is given a relative address. Therefore, the CPU will be able to identify which photodiode generates the signal, to decide the impact position of eqns. 1-5, and to calculate the speed of the projectile.Fig. 5 Block diagram of digital signal processing circuit 4 Accuracy of EOTS4.1 Accuracy of speed measurementThe accuracy of projectile velocity measurement with sky-screens has been deduced by Hartwig [8] asS v T v v S∆+∆∆≤ (8) where parameters were the same as eqn. 6 used. Δv , ΔS and ΔT are values of maximum error in v , S and T , respectively. In EOTS, photodiodes are directed by nonuniform optical power, as described in Section 3.1, which implies that different analogue channels will have different response times, as though they are activated in the same way. Fig. 6 describes the typical input and output waveforms of an analogue channel when a projectile passes through the light screen. The dotted line is theFig. 6 Typical input and output waveform of analogue channelresponse of the weaker optical input with respect to the solid line. In this Figure, the optical power density directed onto the photodiode is considered to be constant along the x-axis. Referring to the solid line, the projectile touches the light screen at T1and entirely blocks laser beams at T2; the activated photodiode current I D drops from I DH to I DL.The output voltage V0of the analogue channel then rises to a saturation voltage V sat. The counter is not triggered until V0is larger than V TH. The interval from T1 to the time that V0equals V TH is called the response time t r From Fig. 6, we can realise that a different input power variation with time will produce a different output response time t r. Therefore, the ΔT of eqn. 8 should include Δt r, for EOTS, where Δt r, is the worst-case difference, i.e., the largest t r of the first optical gate minus the smallest t r of the second optical gate. Table 1 lists the simulation results of Δt r of the analogue circuit with respect to different projectile velocities using PSpice.Table 1 Simulation results of Δt, respect to projectile speed4.2 Accuracy of position measurementConsidering an EOTS structure in Fig. 3, if a photodiode, numbered n, is activated by a projectile, the exact shot-position angle δe , will be within the range1arctan()arctan(),1e n n n N N Nδ-≤≤≤≤ (9) orarctan()arctan(),12212e N N N n N N n N nδ≤≤+≤≤-+- (10) Referring to eqns. 1 and 2, eqns. 9 and 10 express that the worst-case deviation of δe , Δδ is caused by half-photodiode-spacing shift of measuring ambiguity. Thus, the deviations of the y-axis and z-axis can be deduced as1212y y y δδδδ∂∂∆=∆+∆∂∂ (11) and1212z z z δδδδ∂∂∆=∆+∆∂∂ (12) Where Δδ1 and Δδ2 are Δδ of the first and the second optical gate, respectively.2122112sec tan (tan tan )D y δδδδδ∂=-∂+ (13) 2122212tan sec (tan tan )D y δδδδδ∂=∂+ (14) 22122112sec tan (tan tan )D z δδδδδ∂=∂+ (15) and22122212tan sec (tan tan )D z δδδδδ∂=∂+ (16) It is obvious from eqns 9-16 that N has to be increased as the position accuracy needs to be better for a same size of D.Fig. 2 shows the intersection of the two light screens in the target area where intervals between photodiodes are considered to be constant. As indicated in this Figure, different detector positions will produce different resolutions. Fig. 7 shows simulation results of the worst-case deviations on the y-axis (or z-axis). The shot-position angle δ1, is fixed at 45º and the activated photodiode of the second optical gate varies from number 40 to 360 on an EOTSwith D = 1000mm and 2N = 400. Fig. 7 shows deviations on the y-axis (or z-axis) of less than 1mm corresponding to certain photodiodes that are numbered approximately from 120 to 280.A pentagon-shaped region, which is shown in Fig. 2 and has an accuracy better than 1mm, also corresponds to those photodiodes.Fig. 7 The worst-case deviation on y-axis and z-axis as δ1 is fixed at 45º5 Experimental resultsA prototype EOTS was used in the experiments. The main specifications of the system are listed as follows: d = 0.81mm, w = 2.5mm, S = 635mm, D = 1000mm, 2N = 384 and laser output optical power P = 7.5mW. We hung up a paper target behind EOTS for comparison. Fig. 8 shows the y and z coordinates of nine impact points from a 0.38in. pistol. The impact positions and the velocities were measured by EOTS. In Fig. 8, the two crosses at the bottom indicate the positions of cylindrical mirrors. Table 2 compares the results generated by EOTS with the measurement results from the paper target. The standard deviation is less than 1mm.6 Discussion and conclusionsThis paper presents a novel electro-optical target system for small calibre projectiles. Position and speed data can be generated instantaneously by the microcomputer-based control unit with the addition of appropriate software. The most accurate region of positioning, which is a pentagon-shaped area, distributes over the centre of the target area. The accuracy of position and speed measurement has been analyzed in this paper. To improve the speed accuracy, we should reduce the influence of the response time difference. To increase the distance between the two light screens, of course, is another method to improve the speed accuracy, but the position accuracy will become worse. To improve position accuracy, the photodiode array which has less space between two adjacent photodiodes is suggested.Fig. 8 The computer printout of EOTS, origin is shifted to centre of the target area The measured speed range of EOTS is from subsonic to supersonic. A speed accuracy of better than 0.3% is accomplished. With a different design concept, EOTS need not synchronized with the firing signal as EYS. It is always ready for any advancing projectile as the power of EOTS has been turned on.Fig. 9 Laser beam directs on a bent cylindrical mirrorIf a slightly bent cylindrical mirror were used (Fig. 9), the light screen could extend a few degrees in the x-direction. This makes optics alignment easier and insensitive to vibrations. However, the surface quality of the cylindrical mirror is critical to the uniformity of the fan-shaped beam in the x-direction. The nonuniformity of the fan beam in the x-direction will enhance the sensitivity to vibrations.Table 2 List of results measured by EOTS and by artificialComparing EOTS with EYS and other conventional methods, EOTS has the following advantages:(a) It can measure position and speed precisely and simultaneously.(b) Its optical system is simple and easy to set up.(c) It is insensitive to vibrations if a bent cylindrical mirror is used.(d) Its speed range covers subsonic to supersonic.References[1] BETTERMANN, P, and MAYER, F. Handbook on weaponry. Rheinmetall GmbH, Dusseldorf, 1982.[2] FARRAR, C.L., and LEEMING, D.W. Military ballistics. Brassey’s Publishers Limited, 1983.[3] CRITTENDEN, E.C., KING, R.A., and ANDREWS, T.C. Target measurement system for precise projectile location. US Paten No.3727069, 1973.[4] BAILEY, T.B., and BATES, J. Electro-optical projectile analyzer. US PatentNo.4272189, 1981.[5] DECK, L.L. An optical device for rapid measurement of the speed, dispersion, attack angle and shock wave of high velocity small caliber projectiles. Proceeding of 10th International Symposium on Ballistics, 1987, 1,pp. 1-9.[6] LU, S.T., YU, A.T, and CHOU, C. Electro-optics target for position and speed measurement, Proc. SPIE, 1988, 981, pp.250-254[7] TUINENGA, P.W. SPICE a guide to circuit simulation and analysis using PSpice. Prentice-Hall, 1988.[8] HARTWIG, R. Accuracy of velocity measurement of projectiles with fins and tracers by means of sky-screens. J. Ballistics, 1986, 9, (3), pp.2299-2310.光电目标位置和速度测量系统摘要本文介绍了一种光电目标系统(EOTS)，其速度测量范围从亚音速到超音速。
信息工程 外文翻译 外文文献 英文文献 光电编码器原理及应用电路
Principle and application of the photoelectric encoder circuitAccording to the test principle, encoder can be divided into optical type, magnet, inductive and capacitive. According to its calibration method and signal output form, can be divided into incremental, absolute type and hybrid 3 kinds.Incremental encoder is directly for the use of photoelectric conversion principle output three square wave pulsed A, B and Z phase; A, B two groups of pulse phase difference 90 DHS, thus can easily tell direction of rotation, and Z for every turn in a pulse, used to benchmark positioning. Its advantages are simple structure, mechanical principle of average life expectancy in the tens of thousands of hours above can be, strong anti-jamming capability, high reliability, suitable for long distance transmission. Its defect is unable to output shaft rotation absolute location information.Absolute encoder is direct output digital quantity sensor, in its circular yards plate along radial direction several concentric yards way, each of which way the by pervious to light and opaque and sector of the sector, adjacent code word number is double relationship, yards dish the code word is its binary number of digits, digital side in the code salver illuminant, another side corresponding to every one yard way have a photosensitive component; When yards in different position, disk by various photosensitive components according to the corresponding light or not conversion, forming a binary number level signal. The characteristics of the encoder counter and axis is not in any position can be read out a fixed position and corresponding digital yards. Obviously, code word, the more the better the resolution, for an N binary resolution coder code salver must have N barcode way.For an N binary resolution coder code salver must have N barcode way. At present domestic have 16 bits of absolute encoders products.Absolute photoelectric encoder is use natural binary or circulation binary (Gregory yards) manner photoelectric conversion. Absolute photoelectric encoder and incremental encoder difference in disk pervious to light, opaque line graph, absolute encoder can have some code, according to read yards plate coding, detection absolute position. Code design can use binary code, recycling yards, binary fill yards, etc. Its features are:(1) can directly read Angle coordinate of the absolute value;(2) have no cumulative error;(3) power excision location information would be lost. But the resolution is decided by the binary digits, i.e. precision, currently depends on digits 10, 14 and so on many kinds.Hybrid absolute encoders, it outputs two group of information: a group of information used to test with absolute poles position, information function; Then another group the same output information incremental encoder.Photoelectric encoder is an Angle (angular velocity) detection device, it will input shaft Angle to using photoelectric conversion principle amount converted into electrical impulses or digital quantity, with small size, high accuracy, high reliability, etc. The interface digital It is widely used in nc machine tools, rotating table, servo drive, robots, radar and military goals determination, need to detect the device and equipment in perspective.EPC - 755A photoelectric encoder is good performance in Angle measurement, displacement measurement anti-interference ability strong and stable and reliable, and the output pulse signal, and the pulse signal can be obtained by counting is measured after digital signal. Therefore, we are developing automobile driving simulator, the steering wheel rotation Angle measurement choose EPC - 755A photoelectric encoder, the output circuit as the sensor type selection, open collector output resolution choose 360 pulse/circle, considering the steering wheel rotation is bidirectional, both clockwise and counterclockwise, also can output signal encoder to phase discrimination to count.When photoelectric encoder clockwise, channel A output waveforms output waveform advance channel B, D flip-flop 90 ° output Q (waveform W1) high level, Q (waveform W2) for low level, top and open, counting pulse sr W3) by (waveform, send to the 74LS193 two-way counter with pulse, input CU addition count; At this time, with closed, its below sr output high level (waveform W4). When photoelectric encoder when A counterclockwise, channel output waveform of output waveform than channel B, D flip-flop 90 °delay output Q (waveform W1) for low level, Q (waveform W2) high level, top and shut, its output sr for high level (waveform W3); At this time, with open, count below sr W4) by (pulse waveform, send to two-way counter reduced input pulses 74LS193, subtraction count CD.Steering wheel clockwise and counter-clockwise, the maximum rotation Angle are two laps half, choose resolution for the 360 pulse/laps of coder maximum output pulse count for 900; The actual use of three slices of 74LS193 with counts circuitcomposed, on the system electric initialization, first to the reset (CLR signal), then its initial set to 800H, namely 2048 (LD signal); So, when the steering wheel clockwise, the output of the counts circuit for 2048 ~ 2948, scope of steering wheel counter-clockwise, when the output of the counts circuit range of 2048 ~ 1148; Counts circuit D11 D0 ~ the data sent to output data processing circuits.In practice, frequently made the steering wheel clockwise and counterclockwise rotation, and because it has quantizing error, work a longer period of time, the steering wheel back after when output may not 2048 counts circuit, but several words deviation; In order to solve the problem, we added a steering wheel back in after work, system test circuits, data processing circuit in the operating state of the simulator, the system checks back when, if the steering wheel in detection circuit in the back, and counts circuit in the state, data output is not to count 2048 reset circuit of the initial value and reset.The rotary, photoelectric encoder its shaft and gravity measurement instrument connected to compensate knob axis. Gravity surveying instrument compensation, the angular knob is transformed into a signal quantity amount; Rotary two kinds of photoelectric encoder, absolute encoder and incremental encoder.Incremental encoder is pulse form output sensor, its code than absolute encoders code salver disk much easier and higher resolution. General need only three barcode way, here's code word has actually don't have absolute encoders code word meaning, but produce counting pulse. It WaiDao and the code salver middle way have same number of uniform distribution pervious to light and not pervious to light the sector (grating), but two way sector mutual stagger half an area. When code salver turns, its output signal is for 90 ° phase of the A and B phase pulse signal and only A third yards of the slit pervious produced tao pulse signal (it as the benchmark code salver position, to count the system to provide an initial zero signal). From A, B two output signal phase relationships (advanced or lag) can judge the direction of rotation.Photoelectric encoder is not installed in motor shell, but rather on the basis of motor stent to create a fixed installation of photoelectric encoder is independent, photoelectric encoder axes and motor shaft center must at the same level, two axis adopt soft rubber or nylon hose connections, in order to reduce motor of photoelectric encoder impact load of mechanical shock.Reasonable choice of photoelectric detection device output signal transmission medium, adopt double twisted screened cable replace common screened cable.Double twisted shielding cable has two important technical characteristics of cable, one is by electromagnetic interference with strong protection ability, because the space is electromagnetic field of interference current online can cancel each other out. Double twisted shielded cable is another technical characteristics after mutual twisted line spacing is small, two lines of interference lines of two basic equal distance of shielding network, two lines of capacitance basic and same, it is to suppress common-mode interference effect more apparent.Photoelectric detection devices transmit and receive devices are installed in production site, in use exposed many flaws, its internal factors have external factors, mainly displays in the following aspects:1. Launch device or accept device for mechanical vibration caused by the reasons such as migration or offset, lead to receiving devices can't reliable receives the light signal, but cannot produce electrical signals. For example; Photoelectric encoder used in steel rolling speed regulation systems, because of photoelectric encoder is direct bolted to the shell, the motor shaft of photoelectric encoder by harder spring slice and motor, because motor shaft connected with load is a load of impact that will have steel mill, when caused the vibration of rotor and shell motors. According to the mensuration; After steel time electricity encoder vibration velocity for2.6 mm/s, so that might damage the vibration velocity of photoelectric encoder internal functions. Cause mistakenly hair pulse, leading to control system is not stable or misoperation, cause accidents.2. For photoelectric detection device installed in production site, production site environmental factor influence by photoelectric detection device can't reliable led to the work. Such as the installation position high temperature, humidity is big, cause photoelectric detection device internal electronic components properties change or damaged. For example in the caster is sending a tracking system, because led ingots photoelectric detection device the installation position near the slab, ambient temperature high and cause photoelectric detection device signal or damaged by mistake, and cause production or personal accident.3. All kinds of electromagnetic interference source production site, photoelectricity detecting devices of the interference, causing photoelectric detection device output waveform distortion distortion, and makes the system occurred maloperation or trigger production accidents. For example; Photoelectric detection device installed in production equipment, its signal via cable ontology to controlsystem's distance transmission in commonly 1.02-3.20m ~ 100m, transmission cable though generally choose more, but due to the core shield cable conductor resistance and the line of cable capacitance between influence plus and other cable laying together, vulnerable to all sorts of electromagnetic interference effects, therefore cause waveform distortion, which makes feedback to speed regulation system of signal and the actual value deviation, but cause the system precision decline.Photoelectric detection device itself is by electronic components, it constitutes of installation environment has certain technical requirements, especially in a harsh environment use, to take corresponding measures to protect the photoelectric detection device to work in its product requirements under the condition of the technology, can play device technical performance. Otherwise the service life of the photoelectric detection device reliability of its work may be subjected to the influence of different level. Combined with photoelectric detection devices in the production process control application practice, the control system design; Unfavorable use of photoelectric detection device as a signal important control signal, photoelectric device to avoid sudden damage or work unstable (environmental temperature, humidity is big,External mechanical vibration, etc) cause other touch and equipment accidents. In the application of PLC program control system of real optimum process control or interference, to overcome monitoring in system adopts photoelectric device and various existing defects, is the effective way to improve the system reliability.光电编码器原理及应用电路根据测试原理，编码器可分为光学式、磁式、电感和电容式。
光电信息科学与工程专业英语第一节
第1章 科技英语翻译
1 多用动词的现在时 can和may使用频率高
广泛使用被动语句
非限定动词的应用和大量使用后置定语 大量使用常用句型
使用长句
大量使用复合词与缩略词
第1章 科技英语翻译
1.4.3 科技英语的翻译方法与技巧
4. 新词汇 近几十年来，在 现有专业词汇和半专业词 汇的基础上又出现了几种 新的词汇，其构词方法主 要有合成法、混成法、截 短法、缩略法、转化法等 。
第1章 科技英语翻译
1.4 科技英语翻译 翻译是把一种语言所表达的思维内容用另一种语言表达出
来的跨语言、跨文化的语言交际活动。翻译包括口译 (interpretation)和笔译(translation)。在笔译中，又可分为 科技翻译、文学翻译、政论文翻译和应用文翻译等等。
1.2科技英语文体总貌
科技英语要求客观性、准确性和严密性，注重叙事逻辑上
的连贯(Coherence)及表达上的明晰(Clarity)与畅达 (Fluency)，避免行文晦涩。 科技英语力求平易(Plainness)和精确(Preciseness)，避免 使用旨在加强语言感染力和宣传效果的各种修辞格
（2）Maiman’s invention of the laser provided new sources of very intense, coherent and highly directional light beams. 梅曼发明了激光器，提供了一种新光源，可产生极强的、 相干的和高度定向的光束。“发明”英译时因作主语故用 名词invention。
9. 语篇重构
语篇重构就是对原文的结构和语言进行较大幅度的 改动，脱离原句的层次和结构安排，按汉语叙事伦 理的习惯重新组合句子，摆脱了原文的语序和句子 形式的约束，使译文自然、流畅，更加符合汉语的 表达习惯，以期在更深的层次上达到与原文的对等。
光电信息科学与工程专业英语教程第二版
光电信息科学与工程专业英语教程第二版1. 引言光电信息科学与工程专业是当今世界领先的学科之一，涵盖了光电子技术、信息处理技术和通讯技术等多个领域。
随着科技的不断进步和发展，对于光电信息科学与工程专业的英语教育需求也日益增加。
为了满足学生和教师的需求，光电信息科学与工程专业英语教程第二版应运而生。
2. 课程设置光电信息科学与工程专业英语教程第二版紧密围绕光电信息科学与工程专业的学科特点和实际需求，涵盖了光学基础、激光技术、光电子器件、光电信息处理、光纤通信等内容。
教程共分为十个单元，分别为：2.1 光学基础2.2 光电信息处理技术2.3 光通信技术2.4 光纤通信技术2.5 激光技术2.6 光电子器件2.7 光信息处理技术2.8 光学材料2.9 光电信息系统集成2.10 光电信息技术应用每个单元均包括了相关领域的英语学习内容，涵盖了基本概念、原理、技术、应用等方面的知识，以帮助学生全面了解和掌握光电信息科学与工程专业的相关知识。
3. 教学理念光电信息科学与工程专业英语教程第二版秉承了“理论通信实际、以学生为本”的教学理念，旨在帮助学生在学习英语的过程中更好地理解相关专业知识，提高科技英语应用能力。
教程注重理论与实践相结合，通过案例分析、实验操作、专业论文阅读等方式，帮助学生将英语知识与光电信息科学与工程专业知识相结合，培养学生的创新意识和实际应用能力。
4. 教学特色光电信息科学与工程专业英语教程第二版具有以下教学特色：4.1 紧密结合专业知识教程中的每个单元都紧密结合了光电信息科学与工程专业的相关知识，内容全面、深入。
学生在学习英语的也能够了解光电信息科学与工程专业的最新发展和应用。
4.2 实践能力培养教程强调实践能力的培养，通过案例分析、实验操作等方式，帮助学生将所学知识应用到实际工程中，提高学生的解决问题的能力和创新意识。
4.3 强调专业素养教程注重培养学生的专业素养，通过专业论文阅读、学术讨论等方式，帮助学生了解专业领域的最新研究成果和发展动向，提高学生的科研能力和学术素养。
光信息专业外语课程教学大纲
光信息专业外语》课程教学大纲【课程编号】：【英文译名】：Professional English for Optical information specialty【适用专业】：光信息科学与技术专业本科生【学分数】：4【总学时】：64 【实践学时】：0一、本课程教学目的和课程性质本课程是为光信息科学与技术专业学生开设的一门重要的专业课，它是在大学英语的基础上，通过英语方式对现在的物理知识进行进一步了解和认识以及对原有物理知识的扩展。
它使学生初步掌握力学、电磁学、热学、光学、声学和粒子物理学中的英语词汇，学会阅读本专业英语资料的技巧与方法。
它有助于拓展本专业学生的知识面，增强国际交流与沟通的能力。
二、本课程的基本要求1、掌握力学、热学、光学、声学和电磁学中的专业英语词汇，了解粒子物理学中的常见词汇。
2、通过对专业英语文献的学习，逐步掌握阅读专业外文资料的常用技巧与方法。
在借助必要的词汇工具书的基础上，能达到独立阅读、理解和初步翻译外文资料的目的。
三、本课程与其他课程的关系在学习本课程前应修完大学英语、力学、热学、光学、和电磁学等课程。
四、课程内容UNIT 1 PHYSICS ，HEAT （12 学时）主要内容：1.1PHYSICS1.2SOLID-STATE PHYSICS1.3NUCLEAR PHYSICS1.4THERMODYNAMICS1.5HEAT1.6THERMODYNAMICS1.7TEMPERATURE1.8SCALES OF TEMPERA TURE1.9SPECIFIC HEAT CAPACITY ，BRITISH THERMAL UNIT ，CALORIE1.10HEAT CONDUCTION ，INVERSE SQUARE LAW11.12INSULATION1.13EXPANSION ，EVAPORATION1.14CRYOGENICS1.15ABSOLUTE ZERO ，SUPERCOOLING基本要求：1.1了解物理学的几个重要分支，掌握各分支的英语专用词汇。
信息技术相关外文翻译学士学位论文
中文4160字改变信息技术—要从管理开始作者：James D.McKeen and Heather A.Smith起止页码：266-275出版日期（期刊号）：2003出版单位：John Wiley & Sons Ltd第四部分人和生产力信息技术（IT），其本身，并不创造价值，是由人让它来创造价值的。
我们坚信，有效的部署，加上人们拥有的技能和能力，从而可以使他们更有效率。
最主要的是有效的部署。
面临的挑战是要配合技术人员建立有效的组织（在操作方面），（在产品和服务的创造）起作用，并响应客户/供应商的市场。
因此，有效的IT部署的结果应以人为本，效率第一，技术第二。
IT组织没有什么比这更明显的了。
本书的这一部分集锦了人和生产率之间四个关键的方面----补充，发展，成熟的做法，和结果的评估。
18章探讨了补充的问题，“保持和留住最好的”。
本章概述了选择，补充和保留的关键作用，当它涉及到保护内部的热门候选人。
最关键的两个技能无疑是项目管理和领导。
这些技能的发展，是分别在19章介绍，“制定有效的IT项目经理”，在20章中，“发展有效的领导者”。
熟练的技术人员一定能安排高功能的单位组织，最大限度地发挥他们的贡献（支持）其业务。
21章，“它”的最佳实践，概述了成功背后的基本原理关于有效组织和确定了一些行之有效的做法，。
22章，“管理虚拟劳动力”，重点是一个新兴的组织形式来突出关键的管理问题，在一般的组织。
最后一章，“它的测量矩阵”，对组织贡献的评估方法和手段。
有句老话说，“如果它是不可评估的，它就不能被管理”。
战略的实施程序，吸收，发展，和成熟的做法，将未经证实的（可能是无效的）直到可能的测量结果。
18招聘和保留最好的IT招聘和留住优秀的人等于生存。
信息技术（IT）组织也不例外。
优秀的项目经理和熟练的程序员很有价值。
生产率的差异最好的和最贫穷的程序员之间在一个单一的组织可以是十或更大的因素（Marco和Lister，1987）。
光纤通信外文资料及翻译(适用于毕业论文外文翻译+中英文对照)[管理资料]
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附件 1：外文资料翻译译文光纤通信在配电网自动化上的应用1前言广泛分布的电话主导着通讯网络的第一个阶段并贯通了 90多年。
但是，电报领先于电话 30 多年，打字机领先于电话半个世纪。
1844年，电报的发明者，塞缪尔-莫尔斯从华盛顿发送第一条电报给他在马里兰-巴尔的摩的同事—韦尔。
1876年，贝尔发明电话，之后不久，人们就意识到有线电话必须集中到一个中心点上，电话到电话的链接才能建立起来。
这些点是手动开关板，有值班操作员控制。
之后引进了机电开关，在 1889 年，第一个双端可动的步进交换机产生。
第二次世界大战之后，整个长途网络自动化后，自动电话进入了黄金期。
晶体管的发明推动了电子在交换系统中的运用，带来了 20 实际 50年代后期第一代电子交换机的发展。
电子交换机使设计和建成的交换机拥有更大的容量。
通讯网络的第二个阶段发生在 20 世纪 60年代，包含三个主要的里程碑：软件，数字交换，和卫星的发射部署。
通信网络的第三个阶段发生在上世纪 70年代，以数据网络和分组交换技术的引进为特征。
为了实现电脑与分组交换网络的兼容性，1976年，国际电报电话咨询委员会建立了一个世界标准的协议，称为。
这个阶段的通讯网络以局域网的引进和推广为特征。
1959年，光纤的产生在光通信领域带来了跨越式的技术发展。
康宁光纤实验室发布第一个低能耗光纤，可以实现 20Db/km 损耗。
通讯网络的第四个阶段开始在上世纪 80 年代，以综合业务数字网和移动通信的运用为特征。
随着国家经济的发展和人民生活水平的提高，人们对电力的需求日益增长，同时对供电的可靠性和供电质量提出了更高的要求。
配网馈线自动化是配网系统提高供电可靠性最直接有效的技术手段之一。
在近几年国家加大了对城网和农网的改l造，国内各大供电局对配电网自动化的投入也在加大。
在配网自动化实现的过程中，我们发现通信问题是一个难点问题。
在此，仅就光纤通信在配网自动化方面的应用谈一点认识和体会。
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中英文对照外文翻译文献中英文资料对照外文翻译原文1.5 Experimental SetupDue to the many concepts and variations involved in performing the experiments in this project and also because of their introductory nature, Project 1 will very likely be the most time consuming project in this kit. This project may require as much as 9 hours to complete. We recommend that you perform the experiments in two or more laboratory sessions. For example, power and astigmatic distance characteristics may be examined in the first session and the last two experiments (frequency and amplitude characteristics) may be performed in the second session.A Note of CautionAll of the above comments refer to single-mode operation of the laser which is a very fragile device with respect to reflections and operating point. One must ensure that before performing measurements the laser is indeed operating single-mode. This can be realized if a single, broad fringe pattern is obtained or equivalently a good sinusoidal output is obtained from the Michelson interferometer as the path imbalance is scanned. If this is not the case, the laser is probably operating multimode and its current should be adjusted. If single-mode operation cannot be achieved by adjusting the current, then reflections may be driving the laser multimode, in which case the setup should be adjusted to minimize reflections. If still not operating single-mode, the laser diode may have been damaged and may need to be replaced.WarningThe lasers provided in this project kit emit invisible radiation that can damage the human eye. It is essential that you avoid direct eye exposure to the laser beam. We recommend the use of protective eyewear designed for use at the laser wavelength of 780 nm.Read the Safety sections in the Laser Diode Driver Operating Manual and in thelaser diode section of Component Handling and Assembly (Appendix A) before proceeding.1.5.1 Semiconductor Diode Laser Power Characteristics1.Assemble the laser mount assembly (LMA-I) and connect the laser to its power supply. We will first collimate the light beam. Connect the laser beam to a video monitor and image the laser beam on a white sheet of paper held about two to ten centimeters from the laser assembly. Slowly increase the drive current to the laser and observe the spot on the white card. The threshold drive current rating of the laser is supplied with each laser. Increase the current to about 10-20 mA over the threshold value.With the infrared imager or infrared sensor card, observe the spot on the card and adjust the collimator lens position in the laser assembly LMA-I to obtain a bright spot on the card. Move the card to about 30 to 60 centimeters from the lens and adjust the lens position relative to the laser to obtain a spot where size does not vary strongly with the position of the white card. When the spot size remains roughly constant as the card is moved closer or further from the laser, the output can be considered collimated. Alternatively, the laser beam may be collimated by focusing it at a distance as far away as possible. Protect fellow co-workers from accidental exposure to the laser beam.2.Place an 818-SL detector on a post mount (assembly M818) and adjust its position so that its active area is in the center of the beam. There should be adequate optical power falling on the detector to get a strong signal. Connect the photodetector to the power meter (815). Reduce the background lighting (room lights) so that the signal being detected is only from the laser. Reduce the drive current to a few milliamperes below threshold and, again, check to see that room light is not the dominant signal at the detector by blocking the laser light.3. Increase the current and record the output of the detector as a function of laser drive current. You should obtain a curve similar to Figure 1.2. If desired, the diode temperature may also be varied to observe the effects of temperature on threshold current. When examining laser diode temperature characteristics, the laser diode driver should be operated in the constant current mode as a safeguard against excessive currents that damage the diode laser. Note that as the diode temperature is reduced, the threshold decreases. Start all measurements with the diode current off to prevent damage to the laser by preventing drive currents too high above threshold. To prevent destruction of the laser, do not exceed the stated maximum drive current ofthe laser.1.5.2 Astigmatic Distance CharacteristicsThe laser diode astigmatic distance is determined as follows. A lens is used to focus the laser beam at a convenient distance. A razor blade is, then, incrementally moved across the beam to obtain data for total optical power passing the razor edge vs. the razor blade position. A plot of this data produces an integrated power profile of the laser beam (Figure 1.9a) which through differentiation exposes the actual power profile (Figure 1.9b) which, in turn, permits determination of the beam diameter (W).A beam diameter profile is obtained by measuring the beam diameter while varying the laser position. Figure 1.9c illustrates the two beam diameter profiles of interest: one for razor edge travel in the direction perpendicular to the laser diode junction plane and the other for travel in the direction parallel to the junction plane. The astigmatic distance for a laser diode is the displacement between the minima of these two profiles. This method is known as the knife edge technique.1. Assemble the components shown in Figure 1.8 with the collimator lens (LC), in the rotational stage assembly (RSA-I), placed roughly 1 centimeter away from the laser. The beam should travel along the optic axis of the lens. This is the same lens used in collimating the laser in the previous setup. The approximate placement of all thecomponents are shown in the figure. Make sure that the plane of the diode junction (xz plane in Figure 1.1) is parallel with the table surface.2. Due to the asymmetric divergence of the light, the cross-section of the beam leaving the laser and, further, past the spherical lens is elliptical. The beam, thus, has two distinct focal points, one in the plane parallel and the other in the plane perpendicular to the laser diode junction. There is a point between the two focal points where the beam cross-section is circular. With the infrared imager and a white card, roughly determine the position where the beam cross-section is circular.Figure 1.9 – Procedure for finding astigmatic distance.3. Adjust the laser diode to lens distance such that the razor blades are located in the xy plane where the beam cross-section is circular.4. Move the laser diode away from the lens until minimum beam waist is reached at the plane of razor blades. Now, move the laser diode about 200 µm further away from the lens.5. Move razor blad e 1 in the x direction across the beam through the beam spread θx and record the x position and detected intensity at each increment (≤100 µm increments). The expected output is shown in Figure 1.9. The derivative of this curve yields the intensity profile of the beam in the x direction from which the beamdiameter is determined.6. Repeat with razor blade 2 for θy in the y direction.7. Move the laser closer to the lens in increments (≤50 µm) through a total of at least than 500µm. Repeat Steps 5 and 6 at each z increment, recording the z position.8. Using the collected data, determine the beam intensity profiles in the x and y directions as a function of the lens position z. This is done by differentiating each data set with respect to position. Then, calculate the beam diameter and plot as a function of z. The difference in z for the minimum in θx and θy is the astigmatic distance of the laser diode. Use of computer software, especially in differentiating the data, is highly recommended.If the laser junction is not parallel to the table surface, then for each measurement above, you will obtain an admixture of the two beam divergences and the measurement will become imprecise. If the laser is oriented at 45° to the surface of the table, the astigmatic distance will be zero.Different laser structures will have different angular beam divergences and, thus, different astigmatic distances. If you have access to several different laser types (gain guided, index guided), it may be instructive to characterize their astigmatic distances.1.5.3 Frequency Characteristics of Diode LasersIn order to study frequency characteristics of a diode laser, we will employ a Michelson interferometer to convert frequency variations into intensity variations. An experimental setup for examining frequency and, also, amplitude characteristics of a laser source is illustrated in Figure 1.10.1. In this experiment, it is very possible that light may be coupled back into the laser, thereby, destabilizing it. An optical isolator, therefore, will be required to minimize feedback into the laser. A simple isolator will be constructed using a polarizing beam splitter cube and a quarterwave plate. We orient the quarterwave plate such that the linearly polarized light from the polarizer is incident at 45° to the principal axes of the quarterwave plate so that light emerging from the quarterwave plate is circularly polarized. Reflections change left-circular polarized light into right-circular or vice versa so that reflected light returning through the quarterwave plate will be linearly polarized and 90° rotated with respect to the polarizer transmission axis. The polarizer, then, greatly attenuates the return beam.In assembling the isolator, make sure that the laser junction (xz plane in Figure 1.1) is parallel to the surface of the table (the notch on the laser diode case points upward) and the beam is collimated by the lens. The laser beam should be parallel tothe surface of the optical table. Set the polarizer and quarterwave (λ/4) plate in place. Place a mirror after the λ/4 plate and rotate the λ/4 plate so that maximum rejected signal is obtained from the rejection port of the polarizing beam splitter cube as shown in Figure 1.11. When this signal is maximized, the feedback to the laser should be at a minimum.2. Construct the Michelson interferometer as shown in Figure 1.12. Place the beam steering assembly (BSA-II) on the optical table and use the reflected beam from the mirror to adjust the quarterwave plate orientation. Set the cube mount (CM) on the optical breadboard, place a double sided piece of adhesive tape on the mount, and put the nonpolarizing beam splitter cube (05BC16NP.6) on the adhesive tape. Next, place the other beam steering assembly (BSA-I) and the detector mount (M818BB) in location and adjust the mirrors so that the beams reflected from the two mirrors overlap at the detector.When long path length measurements are made, the interferometer signal will decrease or disappear if the laser coherence length is less than the two way interferometer path imbalance. If this is the case, shorten the interferometer until the signal reappears. If this does not work, then check the laser for single-mode operation by looking for the fringe pattern on a card or by scanning the piezoelectric transducer block (PZB)in BSA-II and monitoring the detector output which should be sinusoidal with PZB scan distance. If the laser does not appear to be operating single-mode, realign the isolator and/or change the laser operating point by varying the bias current. Additionally, to ensure single-mode operation, the laser should be DC biased above threshold before applying AC modulation. Overdriving the laser can also force it into multimode operation.3. The Michelson interferometer has the property that depending on the position of the mirrors, light may strongly couple back toward the laser input port. In order to further reduce the feed-back, slightly tilt the mirrors as illustrated in Figure 1.13. If still unable to obtain single-mode operation, replace the laser diode.4. Place a white card in front of the detector and observe the fringe pattern with the infrared imager. Slightly adjust the mirrors to obtain the best fringe pattern. Try to obtain one broad fringe.5. Position the detector at the center of the fringe pattern so that it intercepts no more than a portion of the centered peak.6. By applying a voltage to the piezoelectric transducer block attached to the mirror (part PZB) in one arm of the interferometer (i.e. BSA-II), maximize the output intensity. The output should be stable over a time period of a minute or so. If it is not, verify that all components are rigidly mounted. If they are, then room air currents may be destabilizing the setup. In this case, place a box (cardboard will do) over the setup to prevent air currents from disturbing the interferometer setup.7.Place the interferometer in quadrature (point of maximum sensitivity between maximum and minimum outputs of the interferometer) by varying the voltage on the PZB.8. The output signal of the interferometer due to frequency shifting of the laser is given by ∆I∝∆φ = 2π/c ∆L ∆ν where ∆L is the difference in path length between the two arms of the interferometer and ∆ν is the frequency sweep of the laser that is induced by applying a current modulation. Remember that in a Michelson interferometer ∆L is twice the physical difference in length between the arms since light traverses this length difference in both directions. ∆L values of 3-20 cm represent convenient le ngth differences with the larger ∆L yielding higher output signals.Before we apply a current modulation to the laser, note that the interferometer output signal, ∆I, should be made larger than the detector or laser noise levels by proper choice of ∆L and current modulation amplitude di. Also recall from Section 1.3that when the diode current is modulated so is the laser intensity as well as its frequency. We can measure the laser intensity modulation by blocking one arm of the interferometer. This eliminates interference and enables measurement of the intensity modulation depth. We, then, subtract this value from the total interferometer output to determine the true dI/di due to frequency modulation. Apply a low frequency, small current modulation to the laser diode. Note that when the proper range is being observed15mA 10didv v 1--= and1mA 2.0didI I 1-= for the amplitude change only.Recallingi v L c 2di d di dI ∆∆∆=∆∝πφ）（ ,15mA 10~didI Lv 2c --∆π, or15-mA 10L K 2~di dI -∆λπ where K is a detecto r response constant determined by varying ∆L.9. With the interferometer and detection system properly adjusted, vary the drive frequency of the laser and obtain the frequency response of the laser (Figure 1.4 or1.10a).You will need to record two sets of data: (i) the modulation depth of the interferometer output as a function of frequency, and (ii) the laser intensity modulation depth. The difference of the two sets of collected data will provide an estimate of the actual dI/di due to frequency modulation. Also note that if the current modulation is sufficiently small and the path mismatch sufficiently large, the laser intensity modulation may be negligible. You may need to actively keep theinterferometer in quadrature by adjusting the PZB voltage.Make any necessary function generator amplitude adjustments to keep the current modulation depth of the laser constant as you vary the frequency. This is because the function generator/driver combination may not have a flat frequency response. The effect of this is that the current modulation depth di is not constant and varies with frequency. So to avoid unnecessary calculations, monitor the current modulation depth by connecting the LASER MONITOR connector on the laser diode driver system to an oscilloscope and keep the modulation depth constant by adjusting the amplitude of the applied sinusoidal wave as a function of frequency. Record the frequency for your laser at which the thermal contribution to dν/di begins to become negligible and dν/di drops off (see Section 1.3).10. Keeping the above equations in mind, we will, now, measure the FM chirp characteristics of the laser. At a constant current modulation frequency (choose a modulation frequency where dν/di varies rapidly, i.e. where the slope of your grap h from Step 9, which should be similar to Figure 1.10a, is maximum), vary the current modulation depth di for different laser bias levels and derive a curve such as the one in Figure1.10b.The output dν should not vary significantly except around threshold and at high currents.CautionDo not exceed the specified drive currents/output power ratings of the diode or it may be damaged.11. The phase noise characteristic behavior (Section1.4) as a function of interferometer path length imbalance ∆L may be determ ined by inducing phase noise through application of laser current modulation. Make sure that the interferometer is in quadrature.Set the laser diode current above threshold, apply a small current modulation, and fix the modulation frequency at a desired value. Convenient frequencies may include 50 Hz, 2 kHz, and 50 kHz (see Reference 1.5). Monitor the detector output with a spectrum analyzer or an oscilloscope and record the peak-to-peak output intensity at interferometer quadrature. You may accomplish this by manually sweeping the PZB voltage to cause a minimum of π/2 phase shift, recording the maximum peak-to-peak intensity as a function of path length imbalance. It is important to ensure that instrument noise is below the signal levels expected and it is assumed that single-mode operation of the laser is maintained. Curves similar to Figure 1.10c should be obtained.1.5.4 Amplitude Characteristics of Diode LasersThe measurements of the intensity characteristics are taken by placing the detector before the interferometer as in Figure 1.10 or by blocking one mirror in the interferometer. Again, the laser must be operated single-moded with minimum feedback or the noise level and functionality will drastically change. The relative intensity noise (RIN) is defined as 20log(dI/I) where dI is the RMS intensity fluctuations so that for dI~10-4 , the RIN is -80 dB. Normally, these measurements are made with a spectrum analyzer and a 1 Hz bandwidth.When making RIN measurements, electronic and photodetector shot noise must be below the RIN levels. (OPTIONAL) You may determine the shot noise using an incoherent source (e.g. lamp) with an intensity level similar to that of the laser. The resultant frequency spectrum of noise with the light source excited gives a measure of the shot noise level which should be adjusted to be at least 10 dB greater than electronic noise levels. The measured shot noise should be checked with Equation0.47.1. Vary the laser drive current from below threshold through and above the threshold and record the laser output power and intensity noise at a desired frequency using a spectrum analyzer. When you calculate the RIN, assuming that shot and electronic noises are below the RIN level, a plot similar to that presented in Figure 1.10d should be obtained. In most cases, for single-mode operation, the noise peaks at threshold. The shape of the noise curve may vary if the laser is modulated, if it becomes multi-modal, or if the side-mode suppression on a nominally single-mode laser is not adequate (< 20 dB).2. It is instructive to operate the laser with modulation signals of varying depth and/or degrading the isolator performance by rotating the λ/4 plate to increase feedback to the laser. This will illustrate noise properties for various feedback conditions which are important to subsequent sensor and communication experiments. RINs of less than -150dB and -120dB are required for television broadcast signals and sensitive interferometric sensors, respectively.3. The intensity noise of diode lasers has a 1/f characteristic (performance is degraded as the frequency is lowered). With the laser above threshold and the photodetector connected to a spectrum analyzer, determine the RIN as a function of modulation frequency. The response shown in Figure 1.10e should be obtained where the noise becomes white (flat with frequency) starting somewhere between 100 kHz and 1 MHz for typical lasers.NOTE: The Michelson interferometer setup used in this project will again be used in Project3. It may, therefore, save time to proceed directly to Project3 before completing characterization of diode lasers in Project2.中文翻译1.5 实验装置由于在这个项目中执行这个实验时涉及到许多新的概念和变化，也因为它们是初始性的工作，项目1可能是这个实验单元中最耗时的项目。