In this video, we will be discussing the difference between Manchester Encoding and Differential Manchester Encoding.

What is Manchester Encoding?

Manchester encoding is used for synchronizing clock. It is used by physical layer of OSI, so that data and clock of synchronous bit stream is encoded. Since length of each data bit is described by default, it is different from other digital encoding techniques. It came into existence before differential manchester encoding 

Manchester encoding main advantage is signal synchronization. DC component of signal carries no information. This makes it possible that standards that usually do not carry power can transmit this information. Signal rate is the drawback of Manchester Encoding.

The reason is that there is always one transition at the middle of the bit and maybe one transition at the end of each bit. 

What is Differential Manchester Encoding?

Differential Manchester Encoding combines clock and data signals together to form a single synchronizing data stream of two levels. Transition always happens at middle of the bit, but at the beginning of the bit determination of bit values is done. There is transition if next bit is zero and no transition if the next bit is 1. 
Manchester encoding improvement is done in differential Manchester encoding. 

If high and low signal levels have the same magnitude with opposite polarity, the average voltage around each unconditional transition is 0. 0 DC bias reduces necessary transmitting power, minimizes the amount of electromagnetic noise produced by the transmission line, and eases the use of isolating transformers.