Test: Asynchronous Counter - 2 - Electrical Engineering (EE) MCQ

In an n-bit counter, the total number of states = 2ⁿ.
Therefore, in a 4-bit counter, the total number of states = 2⁴ = 16 states.

One of the major drawbacks to the use of asynchronous counters is that High-frequency applications are limited because of internal propagation delays. Propagation delay refers to the amount of time taken in producing an output when the input is altered.

In an asynchronous counter, there isn’t any clock input. The output of 1^st flip-flop is given to second flip-flop as clock input. So, in case of binary down counter the output word decreases by 1.

A binary counter counts or produces the equivalent binary number depending on the cycles of the clock input. Modulus-10 means count from 0 to 9. So, the terminal count is 9 (1001).

Since a counter is constructed using flip-flops, therefore, the propagation delay in the counter occurs only due to the flip-flops. Each bit has propagation delay = 12ns. So, 5 bits = 12ns x 5 = 60ns.

A ripple counter is something that is derived by other flip-flops. It’s like a series of Flip Flops. Output of one FF becomes the input of the next. Because ripple counter is composed of FF only and no gates are there other than FF, so only propagation delay of FF will be taken into account. Propagation delay refers to the amount of time taken in producing an output when the input is altered.

Propagation delay refers to the amount of time taken in producing an output when the input is altered. Internal propagation delay of asynchronous counter is removed by synchronous counter because clock input is given to each flip-flop individually in synchronous counter.

Number of flip-flop required is calculated by this formula: 2^(n-1) 
⇒ N< = 2ⁿ. 2⁴ = 16 and 2³ = 8,
therefore, 4 flip flops needed.

In a n-bit counter, the total number of states = 2ⁿ.
Therefore, in a 3-bit counter, the total number of states = 2³ = 8 states.

A ripple counter is something that is derived by other flip-flops. Its like a series of Flip Flops. Output of one FF becomes the input of the next. Because ripple counter is composed of FF only and no gates are there other than FF, so only propagation delay of FF will be taken into account. Propagation delay refers to the amount of time taken in producing an output when the input is altered.