Page 128 - Handout Digital Electronics

Disadvantages are:

• Slow operation speed. This is caused by their principle of operation, that is , the second flip flop
cannot change its state before the first flip flop has changed its state. Consider a counter with
nine flip flops. For the ninth flip flop to change, the signal must ripple through all the other eight
flip flops.
• Erroneous counting can occur at high clocking frequencies. When using asynchronous binary
counter circuits, the number of flip flops used in implementing the counter is large, adding the time delay
of separate stages together gives a total time delay where the difference in time between the input signal
and the counter output signal is very large. This obviously results in erroneous counting. This also
explains why asynchronous Counters are generally not used in high frequency counting circuits
where large numbers of bits are involved.

Activity

1 Why are asynchronous counters called „ripple „counters?

2 Is it possible to start counting from any digital position?

3 Is it possible to have UP/Down asynchronous counters, yes/no? Explain in each case.

Lecture 16 Video Lecture

Watch the complete explanation of this chapter here:
https://www.youtube.com/watch?v=OkFhV8QJqK8

Lecture 16 Online Quiz

Test your understanding by completing the quiz:
https://forms.office.com/Pages/DesignPageV2.aspx?origin=NeoPortalPage&subpage=design&id=6It6CPsfU
EqeY6fdRNP5cqrl2mW71GRAiQAluYy6dIVUNTlKVjJTWkNDRkZRN0UzWVFaTjg1TVlUTi4u

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