What is the difference between synchronous counter and asynchronous counter

Difference: The trigger signal of the synchronous counter is the same signal, but the trigger signal of the asynchronous counter is different. Synchronous clearing of synchronous counters means that the clearing operation must wait until the clock pulse is valid. For asynchronous counters, clearing means that there is no need to look at the clock pulse, and it can be set to zero immediately as soon as the clear terminal is set.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

Synchronous counter

The synchronous counter refers to the measured cumulative value. Its characteristic is that it greatly increases the working frequency of the counter, corresponding to the asynchronous counter. For synchronous counters, since the clock pulse acts on each flip-flop at the same time, it overcomes the flip-flop step-by-step delay problem encountered by asynchronous flip-flops. Therefore, the operating frequency of the counter is greatly increased. The output difference of the flip-flops at each level is small, and the decoding can be achieved. Avoid spikes; however, if the number of synchronous counter stages increases, the load on the counting pulses will increase.

Asynchronous counter

The asynchronous counter is an asynchronous sequential circuit. Its main feature is that the clock pulse terminals CP of each internal flip-flop are not all connected together, so each flip-flop The flipping moments are first and last, and its output may produce interference glitches, but its circuit structure is simple.

The difference between synchronous counters and asynchronous counters

There are many differences between synchronous counters and asynchronous counters. First of all, in terms of trigger signals, the trigger signals of synchronous counters are the same. One signal, that is to say, the triggers of each stage of the synchronous counter are connected to the same CLK signal, while the trigger signals of the asynchronous counter are different.

Secondly, synchronous counter clearing means that you must wait until the clock pulse is valid before performing the clearing operation. For asynchronous counters, clearing means that you do not need to look at the clock pulse, and only need to set the clearing terminal. It can be reset to zero immediately.

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