Data Encoding & Decoding with Modulation Techniques for AFCAT 2022

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Complete Video at - Data Encoding and Decoding with Modulation Techniques (Computer Science)


  1. Definition of Encoding
  2. Definition of Decoding
  3. Techniques under Encoding
  4. NRZ
  5. NRZI
  6. MANCHESTER Encoding
  7. DIFFERENTIAL Encoding.

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Definition of Encoding

  • It is a process of converting the one type of signals into another form or can be simply defined as the data will be converted into the special type of characters or symbols depending upon the requirement.
  • These specialized characters or symbols will be transferred in the channel while communication and data transfer between sender and receiver.

Definition of Decoding

  • Decoding means that reverse conversion of specialized characters into original text.
  • It will be done at the receiver՚s end.

Benefit of Encoding and Decoding

  • Data can not be hampered or read by any of the intruder in the channel or intermediate path while communication.

Working of Encoding and Decoding

Encoding Decoding

Techniques under Encoding: NRZ

  • NRZ: It stands for Non-Return to Zero.
  • It uses two levels of voltage as binary values i.e.. 0 and 1.
  • 0 represents the negative value and

1 represents the positive value. Voltage will be return to Zero during bit interval.


Techniques under Encoding: NRZI

  • NRZI: It stands for Non-Return to Zero Inverted.
  • Here transmission from high to low and low to high represents transmission by value 1.
  • If there is no transmission, it will be represented by value 0.


Q1. NRZI stands for:


  1. Non Return to Z-Index
  2. Non Return to Zero Inverted
  3. Non Reverse to Zero Index
  4. Non Reverse to Zeroth Inverted

Ans: 2.


Q2. Decoding means:


  1. Converting original text to coded form
  2. Converting coded form to original text
  3. To modify the original data
  4. To sum up the broken data into original form and send it in the communication path

Ans: 2.

  • We learnt about:



#Process of Encoding and Decoding