synchronus reset with simple respected clock.it is required more no of gates,and it is didnt have metastabilty problem.it is working is slow. 2 m, X/ P( d/ K1 J0 k& [2 e- @$ u; t& j0 k$ r
asynchronous reset with out respected to the clock.it is required less no .of gates.it is suffer to the metastability problem.it is working is fast