plz help me....PFD IN phase locked loop

[mytreyi]

i was implemented 4 types of pfds....
using cmos,transmission gate,mpc-pfd,pc-pfd
below graph is mpc pfd result....
plz explain... is it right or not?
how to check this output iam always confusng....
thaq

 

[mytreyi]

phase locked loop

cmos pfd reults...[/img]