(Line Encoding ) Data Transmission And Digital Communication

(Line Encoding ) Data Transmission And Digital Communication

(Line Encoding ) Data Transmission And Digital Communication Lecture 6 2019/1440 By: Elham Sunbu OUTLINE What is line coding? Line coding schemes.

- Unipolar encoding; NRZ - Polar encoding; (NRZ, NR, Manchester, Differential Manchester) Line coding examples.

Digital Transmission Digital transmission is the sending of information over a communications media in the form of digital signals. Digital signals are a sequence of voltage pulses.

They can propagate analog and digital data. They offer better noise immunity, are cheaper to implement in hardware, more secure and also allow data compression, thereby

optimally utilizing the transmission link. 3 Digital Signal Transmission Digital Data transmitted as Digital

Signals Analog Data transmitted as Digital Signals 4 Digital Data Transmitted as Digital Signals

To convert digital data into digital signals. It can be done in two ways, line coding and block coding. For all communications, line coding is necessary whereas block coding is optional.

Here digital data is first encoded into a binary stream. These binary streams are then converted into digital signals by line coding techniques. 5 What is Line Coding? - is the process of converting binary data (a

sequence of bits) to a digital signal. - Different line codes have different attributes. - Best line code has to be selected for a given application and channel condition. 6 Line Coding

7 8 Unipolar Encoding - Unipolar encoding uses only single voltage level to represent data.

- It is also called Unipolar-Non-return-to-zero, because there is no rest condition - In this case, to represent binary 1, high voltage is transmitted

and to represent 0, no voltage is transmitted 9 Polar Encoding - Polar encoding uses two voltage levels (positive and negative).

- Polar encodings is available in four types: 10 Polar Encoding 1.1- Polar NRZL (Non Return to Zero) Level

- Bit 0 is mapped to a negative amplitude. - Bit 1 is mapped to a positive amplitude. 11 Polar Encoding 1.2- Polar NRZI (Non Return to Zero Inverted)

- Bit 0 mapped to no signal level transition. - Bit 1 is mapped to signal level transition at the beginning of the bit interval. Assumption: - The signal level to the left of the bit is high Fig. A and Fig. C - The signal level to the left of the bit is low Fig. B and Fig. D 12 NRZ-L changes voltage level at when a different bit is encountered

whereas NRZ-I changes voltage when a 1 is encountered. 13 Polar Encoding 2- Polar RZ (Return to Zero) - Bit 0 is mapped to a negative amplitude - A for the first half of the symbol duration followed by a zero amplitude for the second half of the symbol

duration. - Bit 1 is mapped to a positive amplitude +A for the first half of the bit duration followed by a zero amplitude for the second half of the bit duration. 14 15 Polar Encoding

3- Polar Manchester Coding - Bit 0 is sent by having a mid-bit transition from high to low. - Bit 1 is sent by having a mid-bit transition from low to high. 16 Polar Encoding 4- Polar Differential Manchester Coding

- Bit 0 is mapped to signal level transition at the beginning of the bit interval. - Bit 1 is mapped to absence of signal level transition at the beginning of the bit interval. Assumption: The signal level to the left of the bit is high Fig. A and Fig. C The signal level to the left of the bit is low Fig. B and Fig. D 17

18 Line Coding Examples 19 Bipolar Encoding Bipolar encoding uses three voltage levels, positive, negative and zero. Zero voltage represents binary 0 and bit

1 is represented by altering positive and negative voltages. 20 Any Question? 21 Thank You

22

Recently Viewed Presentations

  • A Life of Prayer: The PAPA Prayer Galatians

    A Life of Prayer: The PAPA Prayer Galatians

    "Prayer is irksome. An excuse to omit prayer is never unwelcome. When it's over this casts a feeling of relief over the rest of the day. We are reluctant to begin, we are delighted to finish" - C.S. Lewis. 09.29.19...
  • TB Infection Control within the palliative care context

    TB Infection Control within the palliative care context

    The agent - mycobacterium tuberculosis. Has been active in humans for hundreds of years. Acid fast slightly curved rod shaped bacillus 0.2-0.5 microns in diameter; 2-4 microns in length
  • Unit 5 - Stars

    Unit 5 - Stars

    Two hundred million electron volts couldn't even boil a thimbleful of water but would likely kill an amoeba. Splitting a single atom of uranium yields a tiny amount of energy. When we speak of the awesome "power of the atom,"...
  • Context - Macbeth, A Christmas Carol, Blood Brothers and Poetry

    Context - Macbeth, A Christmas Carol, Blood Brothers and Poetry

    Context Revision Cards. Types of context: Historical. Social. Authorial . Audience . Genre. On one side of the card write the context factor, on the other side write down the definition and the link. Genre. Hubris + Tragic Hero. Hubris...
  •  IAEG at a glance Board of Directors Chair:

    IAEG at a glance Board of Directors Chair:

    The current supplier pilot is aimed at testing the data elements and the process for collection to obtain input from suppliers. The team has identified the top 10 industry chemicals and are exploring the possibility for industry R&D collaboration ......
  • Psychological Research Areas - McConnell

    Psychological Research Areas - McConnell

    Psychological Research Areas Social and Personality Social psychology - involves the study of social interactions, stereotypes, prejudices, attitudes, conformity, group behaviours, and aggression Personality psychology - involves the study of personality development, personality change, assessment, and abnormal behaviours Developmental Psychology...
  • Taal als tweesnijdend zwaard - ACTcursus

    Taal als tweesnijdend zwaard - ACTcursus

    Hoe doe je defusie? Uitleg geven en kader bieden. Bewustwording stimuleren. Oefenen en doen. Bekrachtigen van defusie. Model staan. Focus op functie. Ontregelen van logisch denken
  • A Very Early Rehabilitation Trial (AVERT) main results ...

    A Very Early Rehabilitation Trial (AVERT) main results ...

    A Very Early Rehabilitation Trial (AVERT):Primary outcome at 3 months post stroke The AVERT Trial Collaborationgroup . Jacqueline Ancliffe MCSP, MSc, FACP. on behalf of . The AVERT Trial Collaboration Group. 56 hospitals in five countries.