Asynchronous Counter: With Types, Applications and Explanations

What is Counter?

It is a device that can be counted in any specific event on the demand of means of several times the specific is happening. In computers or digital logic systems, this counter counts and supplies the number of times in which any of the specific processes are happening, based on a clock signal. In general, the type of counter is a sequential digital logic circuit with only the input of are single clock and outputs are multiple clocks. The clock pulse may be either decrease or increase the number.

Types of Counter:

1. Asynchronous Counter
2. Synchronous Counter

What is an Asynchronous Counter?

Those counters that do not operate on simultaneous clocking are known as Asynchronous Counters. In addition, only the asynchronous counter, the first flip-flop flop is externally clocked utilizing a clock pulse rather the input for the flip-flop that is successive will be the output from the previous flip-flop. In the arrangement of the counter, the single clock pulse is not driving in all of the flip-flops. Asynchronous counters are also called Ripple Counters. 

Types of Asynchronous Counter:

1. 2-bit Asynchronous Up Counter

2. 3-bit Up/Down Counter

3. 4-bit Up Counter

1. 2-bit Asynchronous Up Counter:

In 2-bit flip-flops are used to generate a 2-bit asynchronous counter. This is up counter and increasing the count with each of the clock pulses. Counter 22 = 4 separate states (00,01,10,11).

The first flip-flop only receives the clock pulse input. This is used as clock input for the second flip-flop. In T-input the flip flops both are High 1 is managed.

The clock pulse is counted digitally at the outputs that are a more significant bit as(MSB).

Consider the initial flip-flop is QBQA = 00. In the output state, the FF1 will toggle to logic 1 throughout the first clock pulse, and again toggle its output FF1 to logic 0 for the next clock pulse. 

FF1 is like a clock pulse input for the second flip-flop which is FF2. 

In addition, the timing diagram of the flip-flop for each occurrence of the clock pulse happens. It counts from 00 to 11 in its timing diagram and at 11 reaches the counter this is resets to 00.

2. 3-bit Up/Down Asynchronous Counter:

We generate the combining concepts of the Up/Down counter as shown in the figure.

Depending on signal clock input, that may be counter in up to down or down to up and the directions.

Up Counting:

Whether the up or down inputs are 1 after this between the first and third flip-flops of the NAND gates will pass the non-inverted output of FF0 to the input clock of FF1. For as FF1 output of Q will be routed to the FF2 clock input. The final result is that is that in this case, they perform the Up-counting.

Down Counting:

When the Up and Down both inputs are 1 the first and third flip-flops of the NAND gates are inverted outputs of FF0 to the input clock of FF1. For as FF1 output of Q will be routed to the FF2 clock input. The final result is that in this case, they perform the Down-counting. 

The reason is that the additional propagational delay is added to the NAND gate network. The up/down counter is less than the up/down counter. 

3. Four-bit UP Counter:

Whenever the clocked by a continuous source of pulses from an oscillator, this type of circuit generates the following waveforms:

The flip-flop that first has the clock input is +ve edge triggered this toggles with the increasing the edge of the clock signal. 

The duty cycle of the clock signal is less than 50% are example.

Moreover, the clock signal is not symmetrical to generate comfortable ''clean'' output bits in the 4-bit binary sequence. 

The clock signal is used like any one of the output bits in the flip-flop circuit as shown in the figure.

Applications:

• Asynchronous counters are utilized for low-power applications and noise emission is also low.
• And more used as frequency dividers, like by N counters.
• In the Johnson counter and Ring counter, we used.
• For designing the asynchronous decade counter we also use this.
• In addition, used in Mod N ripple counters. For example Mod 3, 4, 8, 14 and Mode 10 so on.

Advantages of Asynchronous Counter:

• It is also known as Ripple Counters and is used in circuits with low speed.
• This is easily designed by the D Flip-flop and T Flip-flop.
• More used in like Divid by n counters that divide the inputs by n, where n is an integer.
• Asynchronous counters are utilized like Truncated counters, design any of the mod number counters like odd Mod or even Mod.

Disadvantages of Asynchronous Counter:

• In high clock frequencies, the counting errors happen because of propagation delay.
• Extra flips-flops are required sometimes for ''Re-synchronous.''
• Additional feedback logic is required to count the sequence of truncated counters.
• In counting the large number of bits, the propagation delay of asynchronous counters is also large.

Final Conclusion of the Asynchronous Counter:

In the Asynchronous Counter we do not utilize the universal clock, in first flip-flop is only applied on the main clock and the rest of the flips flop the output like as clock of the previous flip-flop. Moreover, it is not dependent on the clock signal. Due to the reason that this provides with separate clock signal. 

HAPPY WITH ASYNCHRONOUS COUNTERS!

Most Frequently Asked Questions:

Q: What do you know about some uses of the Asynchronous Counters?

The use is as frequency dividers like divided by N counters. And more use for the applications of the low power and low noise emission, more use in designing the decade counter.

Q: Asynchronous counter is faster or not?

Yes, this operation is faster. Also asynchronous counter is slower the operation. It is also known as a Parallel counter.

Q: Is the working of an Asynchronous Counter?

Normally the working of the team does not demand all members for simultaneously online. Asynchronously the teams work, while the individual person is obtained to enhance their productivity rather than for waiting their tasks completely.