+ All Categories
Home > Documents > Wk2 Transmission Concepts

Wk2 Transmission Concepts

Date post: 02-Jun-2018
Category:
Upload: abaigail-rose-artagame
View: 230 times
Download: 0 times
Share this document with a friend

of 13

Transcript
  • 8/10/2019 Wk2 Transmission Concepts

    1/13

    Data and Information

    Dataany representation, such as a figure or a letter, to

    which meaning can be ascribed.

    InformationAny organized signal

  • 8/10/2019 Wk2 Transmission Concepts

    2/13

    Data Transmission

    Defined as the movement of information over some physicalmedium, using some physical representation appropriate

    to the medium.

  • 8/10/2019 Wk2 Transmission Concepts

    3/13

    Data Communications

    Controlling, checking and handling of the movement ofinformation in a communications-based computer system.

  • 8/10/2019 Wk2 Transmission Concepts

    4/13

    Compression

    The encoding of data so that it requires less disk space forstorage and transmission.

  • 8/10/2019 Wk2 Transmission Concepts

    5/13

    Encryption

    The science of converting computer data and messages tosomething incomprehensible by means of a key, so that it

    can be reconverted only by an authorized recipient holding

    the matching key.

  • 8/10/2019 Wk2 Transmission Concepts

    6/13

    Data Transmission:

    1. Serial TransmissionBits are transmitted one afteranother. (serial-by-bit)

    2. Parallel TransmissionBits are transmitted all at once.

    (parallel-by-bit/serial-by-character)

  • 8/10/2019 Wk2 Transmission Concepts

    7/13

    Modes of Transmission:

    1. Simplex

    2. Half-Duplex

    3. Full-Duplex

    4. Point-to-point

    5. Multi-drop

    I. Bus

    II. Ring

    III. Hub

    IV. Wireless

  • 8/10/2019 Wk2 Transmission Concepts

    8/13

    Data Communications Circuit:

    1. DTE (Data Terminal Equipment)a computer

    transmit and receive equipment.2. DCE (Data Communication Equipment)an

    equipment that interfaces the DTE to the network.

  • 8/10/2019 Wk2 Transmission Concepts

    9/13

    Transmission Methods:

    1. Asynchronousa character-framed transmission

    2. Synchronousa message-framed transmission

    3. Isochronousa synchronous data transmitted without aclocking source

    4. Pleisiochronousa synchronous transmission of varying

    levels of bandwidth

  • 8/10/2019 Wk2 Transmission Concepts

    10/13

    Synchronization:

    1. Network Synchronizationrequired so that station sharing a

    network can transmit and receive in an orderly fashion

    2. Frame Synchronizationrequired to keep track of the individual

    channels in a TDM system

    3. Codeword and node synchronizationrequired to keep tracks of

    block of bits in a bit stream.4. Symbol Synchronizationrequired in order that symbols, which

    may be hidden in a noisy waveform, are sampled at the optimum time

    5. Carrier Synchronizationrequired in order to demodulate a carrier

    modulated wave in the most efficient manner.

  • 8/10/2019 Wk2 Transmission Concepts

    11/13

    Transmission Codes:1. Binary Digit (bit)defined as the amount of information

    derived from the knowledge of two equiprobables and can be

    represented mathematically by a 1 or 0 or electrically by two

    deferring conditions +v orv, on or off.2. Alpha numeric characters are being coded into binary notations.

    BCD (Binary Coded Decimal)a 4-bit code used to

    represent decimal numbers in terms of binary notation. To

    represent alpha information an additional 2 bits is being

    added. (6 bits represents BCD with alphanumeric

    characters)EBCDIC (Extended Binary Coded Decimal Interchange

    Code)an extension of BCD code that uses 8 bits instead

    of six.

    International Alphabet No. 5 (ASCII)a 7-bit code

    developed by ANSI, CCITT and ISO.

    Telegraph Codes (IA 2)the International Alphabet No. 2is a 5-bit code used in telegraphy. Also known as the

    Baudot Code

    UNICODE (Universal Code)An attempt to standardize

    longer and more complex coding scemes used to

    accommodate more complex languages such as Japanese

    and Chinese. Supports 65,536 (216) characters.

  • 8/10/2019 Wk2 Transmission Concepts

    12/13

    Efficiency of CodesThe efficiency of a two-condition code can be expressed by

    the formula:

    Log2N

    E = --------------------

    M

    Where: E = the efficiency of the code

    N = the number of characters or symbols required

    M = the number of bits in the code

  • 8/10/2019 Wk2 Transmission Concepts

    13/13

    Data Transmission Rates

    1. Modulation RateRate at which changes in the condition

    of the circuit can be made in a given time

    2. Data Signaling RateRate at which information can be

    transmitted3. Data (Information) Transfer RateRate at which actual

    data arrives after transmission


Recommended