Text 1. Ultrafast Fiber Switching Devices and Systems Future switching systems are expected to process net data rates approaching a terabit per second (Tbit/s).The terabit benchmark is significant from a research standpoint because it means that the system will require different devices and architectures that are currently in use. These future systems may use some aspect of photonic switching to take advantage of inherent optical properties. “Ultrafast” means having speeds greater than 50 Gbit/s, or at least beyond the speeds that electronic systems may reach.
Devices that are based on “all-optical” interactions rely on virtual transitions in the material: i.e., the interaction is through deformation of wave functions, which is non-resonant and can be almost instantaneous. Since electrons are not “created”, the devices are not limited by carrier recombination times in the material. In general, all optical switching can be realized well below the bandgap of materials, thereby avoiding linear and nonlinear absorption and the related heating effects that can be detrimental at high bit rates. For example, optical fibers are typically used below one fifth of the energy gap and semiconductors may be used below their half-gap energy. Furthermore, unlike electronic devices where the energy incident on the device leads to heating, most of the energy incident on the waveguide or fiber devices is guided and reappears at the output of the device.
Ultrafast devices can be divided into two general categories. The first is a routing switch in which the input is connected to one of several output ports, and the routing is based on either the intensity of the signals or an externally supplied control beam. If only one output port is employed, then the routing switch works like an on off switch. Also, if the routing is based on the intensity of the input, then device may be used as a limiter or a saturable absorber. Routing switches are “physical” switches since photons are physically moved from one port to another. The other category is a logic gate in which a Boolean operation is performed based on the values of the input signals. The logical approach can be powerful because it allows intelligence to be distributed throughout the system (in the sense that one data stream can control another); and this is one reason that modern electronic systems operate based on digital logic.
Routing and logic switches differ fundamentally in the manner of the control. In routing switches, the control is typically in a different physical format than the data, and the control network may be external to the switching fabric. In a logic gate, on the other hand, the control is in the same physical format as the data, and, therefore, the control can be distributed throughout the switching fabric. Another difference between the two devices is the representation of the decision. A routing switch represents its decision by the position or location of data, while the output of a logic gate has a “0” or ”1” logic level. Since routing switches route the same photons from the input to the output, the signals may degrade because of loss, dispersion or cross-talk. In digital logic gates, the signal level and timing is regenerated at the output of each gate by replacing the input photons with new photons from a local power supply. The penalty for high-speed, digital logic-based systems is that the switching energy and power supply requirements are major constraints.
Vocabulary
10.2 Compile the vocabulary (term) log as shown in the preface (part of speech, definition, translation, synonyms and antonyms if possible, example of use). Words (concepts) are given below:
Switching system; data rate; bandgap; a routing switch; switching fabric; cross-talk; a logic gate; dispersion; intelligence (не ум, не интеллект и не разведка!); digital logic; saturable absorber; logical approach; physical format.
10.3 Find in the text and suggest English equivalents for the following:
Коммутационные системы; с точки зрения исследования; присущие
оптические свойства; искажение волновой функции; высокие скорости передачи битов, волновод, выходной порт, маршрутизация, на основе цифровой логики; логический вентиль; с другой стороны; механизм коммутации; отрицательная сторона; виртуальный переход;точка зрения; электропитание; механизм переключения (коммутации); логическая операция; главные препятствия.
Comprehension Check
10.4. Answer the following questions:
1) What is expected to process net data rates approaching a terabit per second?
2) Why is the terabit benchmark significant?
3) What may these future systems use?
4) What does “ultrafast” mean?
5) What do devices based on “all-optical” interactions rely on?
6) Why aren’t the devices limited by carrier recombination times in the material?
7) In what way can all-optical switching be realized?
8) Where does most of the energy incident on the waveguide or fiber devices reappear?
9) How many categories can ultrafast devices be divided into?
10) What can you say about the first category?
11) What happens if only one output port is employed?
12) Why are routing switches called “physical” switches?
13) What is the other category?
14) Why do modern electronic systems operate based on digital logic?
15) How do routing and logic switches differ?
16) How is the signal level and timing regenerated at the output of each gate in digital logic gates?
10.5 Complete the following sentences:
1) “Ultrafast” means having speeds greater than ….. , or at least beyond the speeds that electronic systems may reach.
2) Devices that are ….. rely on virtual transitions in the material.
3) ….. , all optical switching can be realized well below the bandgap of materials.
4) Ultrafast devices can be divided into ….. .
5) If only one output port is employed, then ….. works like an on-off switch.
6) ….. can be powerful because it allows intelligence to be distributed throughout the system.
7) Routing and logic switches differ fundamentally in the manner ….. .
8) In a logic gate, the control is ….. as the data.
10.6 Complete the following sentences using the words from the box:
Phase means include preserved logic decreases
1) All-optical interactions are coherent processes in which the input signal phases are …
2) It ….. that the system will require different devices and architectures than the currently in use.
3) Optics can be used beneficially in photonic interconnections and highly parallel ….operations.
4) As the bit rate increases, the bit period ….. and the tolerance to timing jitter.
5) In a synchronous system all parts must be ….. and frequency locked to a master clock.
6) Sources of pulse distortion ….. nonlinear absorption and low-frequency Raman effects.
Developing language skills
10.7 Translate the following passive constructions paying attention to the verbs followed by prepositions:
1) Electronic computers are paid attention to in this article. 2) The speed of information processing should be paid special attention to. 3) The results of calculations performed by a computer can be fully relied upon. 4) All the achievements of modern science are being made use of in modern production processes. 5) Different types and systems of computing technique were being spoken about at the January conference. 6) I think all the necessary materials should be immediately sent for. 7) What was your experiment followed by? 8) This device should be looked upon as an experimental one. 9) His works are often referred to by other researchers. 10) My decision may be influenced by your advice. 11) The invention is much talked about.
10.8 Read the following text, guess or suggest a title to it, and write a summary (approximately 7 sentences):
Text 2. ________________________
Network Topology is network structure that tells how nodes are connected to form the network. Physical topology is the actual geometric layout of nodes. The basic typologies are Bus, Star and Ring. You can create other topologies like mesh, hybrid, tree topologies by combining and modifying the basic typologies.
The choice of topology for a network will depend upon the choice of transmission media, access method, desired performance, reliability, size, expandability, cost, availability of communication lines etc.
Bus topology is one of the basic topology where nodes (computers and/or network devices) are connected linearly, with each node directly connected to the network cable (known as trunk or bus). A drop cable is connected with the trunk using a T connector. The bus has terminator at both ends which absorb the signal to remove it from bus if it is not picked by any node. Bus topology is easy to implement and extend, easier to identify the cable fault but this topology has disadvantages like limited cable length and number of stations, the problem in network cable (trunk or bus) causes the break down of entire network, and the maintenance cost can be higher in long run.
Ring topology is a network structure where arrangement of nodes forms a loop or ring. The data is sent to only one direction of the ring and each node picks up, checks if it is destined to it, if not re-transmits down to the next neighbor. So the signal quality in ring topology is high. Any data packet if returned to the sender, the sender removes it from ring.
Ring topology performs better under heavy network load than bus topology, does not require network server and it is easier to use optical fibers as transmission media but ring topology has disadvantages like node failure causes network failure, it is difficult to diagnose faults in ring topology, network configuration is difficult.
In Star topology, there is a central computer or network device like hub, switch etc. with which all other nodes are connected (all-to-one connection). The central computer is called hub node and other computers are leaf nodes. All the data passes through the hub node to reach up to its destination. Hub manages and controls all the functions as well as acts as a repeater for the data flow.
Star topology has advantages such as it is easy to install, detect faults and remove parts, no disruptions to the network functioning when adding new nodes or removing nodes. However star topology suffers from drawbacks like heavy dependence on hub node and problem in hub node can cause whole network failure, the performance and scalability (extensibility) of network depends on the capability of hub.
10.9 Make up 10 questions of your own using the information in text 2.
Unit 11
11.1 Read and translate the text. Use a dictionary to help you.
Text 1. Video Conferencing
In a face-to-face meeting, participants automatically filter out routine disturbances in their local environment. In distance conferencing, audio and video disturbances are transmitted to the receiving studios, along with the information that is meant to be sent. Because humans filter extraneous information differently when it becomes magnified to the point when they can distract the audience from getting the intended message.
Videoconferencing studios should provide a normal meeting environment, even though the participants in the meeting may, in fact, be thousands of kilometers apart. Equivalent capabilities must be made available electronically to the meeting parties, including a whiteboard, a document display and, above all, the facility to see, speak and listen normally in a natural and non-intimidating environment.
A videoconferencing studio is normally constructed for four to six participants, sitting along one side of a conference table. Facing them will be a video wall in which the screens and cameras are mounted. For more than three participants, two cameras are recommended. These are mounted near the centre of the video wall and are aimed 'cross-fire' to avoid the unfortunate intimidating effect that follows from a participant staring directly, and apparently fixedly, into the camera whilst, in fact, viewing the main monitor. The use of dual cameras ensures that the image of each person is of reasonable size and that not too much space is registered above and in front of the participants.
The two pictures are combined by a split-screen unit (SSU) into the video frame for transmission. At the remote site, the SSU can de-split the picture on to two screens. If there are three or fewer participants, the SSU can be switched off from the users panel. Fixed camera positioning is generally preferable and is less expensive.
Systems, usually activated by voice switches, which 'zoom-in' on the speaker, are available but have the disadvantage of preventing the remote viewer from seeing the reactions of the local participants.
The cameras should be mounted at median eye height, which is defined as 1.29 meters above floor level. Thus, the main viewing screens, installed close together to provide continuity of the de-split image, must be mounted below the camera level.
Vocabulary
11.2 Compile the vocabulary (term) log as shown in the preface (part of speech, definition, translation, synonyms and antonyms if possible, example of use). Words (concepts) are given below:
Disturbance; cross-fire; voice switches; 'zoom-in'; a split-screen unit; video frame; user panel; voice switches; videoconference; a video wall; to be mounted; to filter out; extraneous; the main monitor.
11.3 Find in the text and suggest English equivalents for the following:
Декомбинированное изображение;непрерывность, последовательность; устройство с комбинированным экраном; обеспечивать, гарантировать; фильтровать, обрабатывать; в естественной и непринужденной обстановке.
Grammar
11.4 Make the following sentences interrogative paying attention to modal verbs with the Infinitive Passive:
1) Data terminal support may be provided by digital telephone sets or data terminals. 2) Access to distance education and the internet can be offered by this new service. 3) The document transmission camera must be ceiling mounted directly above the document field. 4) The pictures can be captured by a digital video camera. 5) Ground communication with new satellites must be established successfully by the network control centre. 6) The two pictures must be combined by a split-screen unit. 7) The cameras should be mounted at median eye height.
11.5 Make an adverb from the given adjectives:
Automatic, different, normal, electronic, direct, apparent, general, local, main, successful.
Comprehension Check
11.6 Answer the following questions:
1) What else is transmitted to the receiving studios, along with the information?
2) What environment should videoconferencing studios provide?
3) How many participants is a videoconferencing studio normally constructed for?
4) How many cameras are recommended for more than three participants?
5) Why are the cameras mounted near the centre of the video wall?
6) What are the two pictures combined by?
7) How should the cameras be mounted?
11.7 Find the English equivalents for the following words and word combinations in the text:
Участники, ограниченная среда, обрабатывать постороннюю информацию, постукивание ручкой, эквивалентные возможности, установить камеры, избегать, двусторонние камеры, изображение каждого человека, для передачи, три или меньше участника, недостаток, на высоте глаз, изображение, сделать доступным, небольшие помехи.
Developing Language Skills
11.8 Complete the following sentences using parts from the list below (a),b),c)…). Translate them.
1) Customer premises wiring is classified as either…….
2) The telephone company is not responsible………..
3) Depression of a line selection button…………..
4) The digital interface allows use………..
5) Analog multiplexing is today……
6) Today's packet-switched networks are most……
a) obsolete in telephony.
b) of feature-rich electronic sets.
c) appropriate and sufficient in communication.
d) connected the hand-set to that line.
e) for nonsystem premises wiring.
f) nonsystem premises wiring, or system premises wiring.
11.9 Analyze the following sentences having complex subject and complex object. Translate them.
1) This investigation is likely to produce good results. 2) Automatic electronic links to customers are expected to be introduced in the second stage of the project. 3) This causes the current to flow in the circuit. 4) Graphic symbols on a map are said to be more readily understood than a written text or synthesized speech. 5) Maintenance costs are likely to be minimal. 6) All messages are likely to be sent over the satcoms network. 7) The nature of the constellation allows a partial service to be offered with just four satellites in orbit. 8) They determined signals on the thinner cable to be less immune and to suffer greater degradation. 9) We observe the transmitting nodes detect collisions when voltages in excess of the amount. 10) The demand for networked digital video conferencing systems on PCs or workstations is expected to be substantial.
11.10 Read the following text, guess or suggest a title to it, and write a summary (approximately 7 sentences):
Text 2. ________________________
Think of an analogy with the postal system. IP is similar to the U.S. Postal System in that it allows a package (a datagram) to be addressed (encapsulation) and put into the system (the Internet) by the sender (source host). However, there is no direct link between sender and receiver.
The package (datagram) is almost always divided into pieces, but each piece contains the address of the receiver (destination host). Eventually, each piece arrives at the receiver, often by different routes and at different times. These routes and times are also determined by the Postal System, which is the IP. However, the Postal System (in the transport and application layers) puts all the pieces back together before delivery to the receiver (destination host).
Note: IP is actually a connectionless protocol, meaning that the circuit to the receiver (destination host) does not need to be set up before transmission (by the source host). Continuing the analogy, there does not need to be a direct connection between the physical return address on the letter/package and the recipient address before the letter/package is sent.
Originally, IP was a connectionless datagram service in a transmission control program created by Vint Cerf and Bob Kahn in 1974. When format and rules were applied to allow connections, the connection-oriented Transmission Control Protocol was created. The two together form the Internet Protocol Suite, often referred to as TCP/IP.
Internet Protocol version 4 (IPv4) was the first major version of IP. This is the dominant protocol of the Internet. However, iPv6 is active and in use, and its deployment is increasing all over the world.
Addressing and routing are the most complex aspects of IP. However, intelligence in the network is located at nodes (network interconnection points) in the form of routers which forward datagrams to the next known gateway on the route to the final destination. The routers use interior gateway protocols (IGPs) or external gateway protocols (EGPs) to help with making forwarding route decisions. Routes are determined by the routing prefix within the datagrams. The routing process can therefore become complex. But at the speed of light (or nearly so) the routing intelligence determines the best route, and the datagram pieces and datagram all eventually arrive at their destination.
11.11 Make up 10 questions of your own about the information in text 2.
Список литературы
1 Г.А. Краснощекова, М.Г. Бондарев и др. Radio Engineering: Учебное пособие. – Таганрог: Изд-во Технологического института ЮФУ, 2007. – 195 с.
2 Freeman,R.L. Fundamentals of Telecommunications, 1999, ISBNs: 0-471-0-471-29699-6 (Hardback); 22416-2 (Electronic)
3 McCarthy, T. R., Duckworth, M. English for Telecoms and Information Technology. Oxford University Press. ISBN 978-0-19-456960-6
4 Компоненты и функции телекоммуникационной системы. http://cdo.bseu.by/dl1/tc/t4_2.htm
5 Glendinning, E.H.,McEwan,J. Oxford English for Information Technology. ISBN 978-019-457492-1
6 Коробейникова Л.Я. Английский язык в сфере информационных и коммуникационных технологий. Методические указания. - Алматы, АУЭС, 2013.
Содержание
Введение…………………………………………………………………3
Unit 1…………………………………………………………………......4
Unit 2……………………………………………………………………..8
Unit 3………………………………………………………………........12
Unit 4………………………………………………………………........16
Unit 5………………………………………………………………........19
Unit 6………………………………………………………………........22
Unit 7………………………………………………………………........28
Unit 8………………………………………………………………........31
Unit 9………………………………………………………………........36
Unit 10…………………………………………………………………..39
Unit 11…………………………………………………………………..44
Список литературы……………………………………………………48
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