(1) The process of converting the already sampled, numerical voltage of the analog input into binary numbers and assembling these with any location and error-related data generated elsewhere into complete digital words, usually of 16 bits. See analog-to-digital converter.
(2) The application of any type of processing to a signal before recording which will later be removed by complementary processing during playback. Most NR systems are good examples of the encoding/decoding process. See stretched.