counter

Question

which of following counters lock out problems are not present:

1.mod-3

2.mod-7

3.mod-1

4. mod-16

what is lock out problems here???

Comments

mod-16 ??

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yes what is lock out problem

Answer 1

Lock out : When the counter enters one of the unused states,then it will not come back from that states ,and counter is said to be locked out.

a) MOD-3 : With 2FF we can have 4 states (0,1,2,3) , but here mod-3 implies 3 states say 0,1,2 if counter enters state 3 we cannot assure it will come back. 

b) MOD-7 : One unused state , same explanation as above.

c) MOD-1: One unused state .

d) MOD-16 : No unused states ,

LOCK OUT not possible in MOD-16.