.


:




:

































 

 

 

 


Fig.1. Metric prefixes, their symbols and their magnitudes




 

Prefix Symbol Decimal Magnitude Multiple
yotta zetta exa peta tera giga mega kilo deci centi milli micro nano pico femto atto zepto yocto Y Z E P T G M k d c m μ n p f a z y 1,000,000,000,000,000,000,000,000 1,000,000,000,000,000,000,000 1,000,000,000,000,000,000 1,000,000,000,000,000 1,000,000,000,000 1,000,000,000 1,000,000 1,000 0.1 0.01 0.001 0.000001 0.000000001 0.000000000001 0.000000000000001 0.000000000000000001 0.000000000000000000001 0.000000000000000000000001 Septillion Sextillion Quintillion Quadrillion Trillion Billion Million Thousand Tenth Hundredth Thousandth Millionth Billionth Trillionth Quadrillionth Quintillionth Sextillionth Septillionth 1024 1021 1018 1015 1012 109 106 103 10-1 10-2 10-3 10-6 10-9 10-12 10-15 10-18 10-21 10-24

 

integers, lines of text, video frames, digital images, etc.), signals (understood as electromagnetic waves (in encoded electrical or optical formats) used to transport the data over a physical medium).

The word 'telecommunication' was adapted from the French word télécommunication, coined in 1904 by the French engineer and novelist Éd. Estaunié. It is a compound of the Greek prefix tele-, meaning "far off", and the Latin communicare, meaning "to share". Thus, telecommunication means literally sharing (sending and receiving) information over distances.

A simple telecommunication system consists of three units that are always present in some form: a) a transmitter that takes information and converts it to a signal; b) a transmission medium, also called the physical channel that carries the signal; c) a receiver that takes the signal from the channel and converts it back into usable information.

Every human being is equipped with a basic communication system. The mouth (and vocal cords) is the transmitter, ears are the receivers, and air is the transmission medium over which sound travels between mouth and ear. Between the speaker and the listener (the receiver), there might be other devices that do or do not introduce their own distortions of the original vocal signal (e.g. telephone, ham radio, IP phone, etc.) Modern telecommunications include the use of such devices as telegraphs, telephones, and teletypes, the exploitation of radio and microwave communications, as well as fiber optics and their associated electronics, plus the use of the orbiting satellites and the Internet.

Telecommunication over telephone lines is called point-to-point communication because it is between one transmitter and one receiver. Telecommunication through radio broadcasts is called broadcast communication because it is between one powerful transmitter and numerous low-power but sensitive radio receivers.

 

3. :

rate , , , ,

frame -

entity ['entɪtɪ] -

coin - , ,

compound ['kɔmpaund] - ; ;

 

4. , :

1. What are some terms and concepts that are used in communications? 2. What is understood as information, message, data and signals? 3. How are the three units of a simple telecommunication system called? 4. What are the functions of a transmitter and a receiver? 5. What are examples of communication systems? 6. Why is telecommunication over telephone lines called point-to-point communication? 7. What does a broadcast communication system consist of?

 

5. , :

; ; ; ; ; ; ; ; ; ; .

6. :

Power level; telecommunications systems; information transfer rate; video frame; transmission medium; usable information; orbiting satellites; radio broadcast; low-power radio receiver; microwave communications.

 

7. :

1. One way understanding how telecommunications systems work and how they are changing is to consider a number... essential concepts. 2. Some designations are not common communications and are included the table completeness. 3. Standard prefixes used metric units designating different physical parameters range size 1024 10-24. 4. Telecommunication means sending and receiving information distances. 5. The word 'telecommunication' was adapted the French word télécommunication. 6. A simple telecommuncation system consists three units. 7. Every human being is equipped a basic communication system. 8. Telecommunication telephone lines is called point-to-point communication because it is one transmitter and one receiver.

 

8. , :

Power

1. He did everything in his power to help me. 2. They have lost the power of speech. 3. Nine is the second power of three. 4. It is necessary to disconnect the power before attempting to repair electrical equipment.

Value

1. She valued the house at $1000. 2. His invention was of high practical value. 3. What is the value of the prize?

Number

1. I gave him my number. 2. A small number of children do not play computer games. 3. I decided not to invite the guests for a number of reasons. 4. Number the pictures from one to five.

 

9. :

Describe, designate, introduce, transfer, equip, inform, distort, listen, measure, refer, exploit.

 





:


: 2016-11-02; !; : 452 |


:

:

.
==> ...

1050 - | 902 -


© 2015-2024 lektsii.org - -

: 0.009 .