What do you mean by meta-stability

Question

What do you mean by meta-stability? Explain when or why it will take place? What are the various ways to avoid this?

Answer 1

Metastable state: An un-known state in between two logical termed as states. This will occur if the output cap is not permitted to charge or discharge completely to the required logical levels.

One of the cases is that if there is a setup time violation, meta-stability will take place. To avoid this, a sequence of FFs is employed (generally 2 or 3) which will eliminate all the intermediate states.