Manchester code

The Manchester code is one of the most used codes in these days. This code adds a clock synchronization (which is essential for the receiver) to the data transmitted. Also, it yields the average DC level at 50%, so the average power still constant and independent on the data stream encoded.
Manchester uses 2 voltage levels, where every symbol has a transition in the middle of the data bit frame for high to low or the opposite. This transition is based on the previous bit frame. A 1 logical lead to a mid-point transition from low to high, and a 0 logical lead to a mid-point transition from high to low.
The figure below shows different transitions for different code methods.