Asynchronous Counters

How many flip-flops are required to construct a mod 128 counter? What is the largest decimal number that can be stored in a mod – 64 counter?

• 7 flip-flops, 127

• 7 flip-flops, 63

• 8 flip-flops, 128

• 8 flip-flops, 64

How many flip-flops will be complemented in a 10-bit binary ripple up counter to reach the next count after the state 0111111111

• 5

• 10

• 1

• 9

What will be the propagation delay in each flip-flop, if 12-bit ripple counter having a modulus of less than or equal to 2^N is clocked at maximum usable frequency of 12 MHz?

• 6.05 ms

• 6.95 ms

• 6.95 ns

• 6.05 ns

A certain JK flip-flop has propagation delay of 40ns. The largest modulus of ripple counter that can be constructed from such flip-flop and still operate up to 8 MHz is ____

• 3

• 4

• 5

• 8

• 010

• 011

• 110

• 111

For the ripple counter shown, if the initial state before the first clock is Q2Q1Q0 = 111, then the state of the counter after 3 clock cycles is ______

• 011

• 101

• 100

• 010

Identify the counter shown in the figure

• Asynchronous down counter

• Asynchronous up counter

• Synchronous down counter

• Synchronous up counter

Symmetrical square wave of time period 100 micro second can be obtained from square wave of time period of 10 micro second by using a:

• Divide by 2 counter

• Divide by 5 counter

• Divide by 8 counter

• BCD counter

Minimum number of J-K flip-flops needed to construct a BCD counter is:

• 2

• 3

• 4

• 5

Maximum operating frequency of mod-200 ripple counter designed by using JK Flipflops each having a propagation delay of 10ns is_____MHz

• 6.25

• 12.5

• 25

• 50