What is the establishment of time?

As for D/A, this is described in D/A conversion rate as an important parameter in describing D/A conversion rate, and generally it refers to the period of time when digital input is inputted and analog output stability is within the normal accuracy. As for A/D, because of the importation of electronic switches, amplifiers have a delay. So a change in inputting voltage to the A/D will take some time to be provided for the accuracy and stability.