Computer Network | Manchester Encoding



Prerequisite – Difference between Unipolar, Polar and Bipolar Line Coding Schemes
Manchester encoding is a synchronous clock encoding technique used by the physical layer of the Open System Interconnection [OSI] to encode the clock and data of a synchronous bit stream.

The binary data to be transmitted over the cable are not sent as NRZ [Non-return-to-zero].

Non-return-to-zero [NRZ] –
NRZ code’s voltage level is constant during a bit interval. When there is a long sequence of 0s and 1s, there is a problem at the receiving end. The problem is that the synchronization is lost due to lack of transmissions.
It is of 2 types:

  1. NRZ-level encoding –
    The polarity of signals changes when incoming siganl changes from ‘1’ to ‘0’ or from ‘0’ to ‘1’. It considers the first bit data as polarity change.
  2. NRZ-Inverted/ Differential encoding –
    In this, the transitions at the beginning of bit interval is equal to 1 and if there is no transition at the beginning of bit interval is equal to 0.

Characteristics of Manchester Encoding –