Define Johnson Counters to Make Simpler Combinational Logic?

The ring counter technique able to be efficiently utilized to implement synchronous sequential circuits. A main problem in the realization of sequential circuits is the assignment of binary codes to the internal states of the circuit in order to reduce the complexity of circuits required. By means of assigning one flip-flop to one internal state it is possible to simplify the combinational logic required to realize the complete sequential circuit and when the circuit is in a particular state the flip-flop corresponding to that state is set to HIGH and all other flip-flops remain LOW.