Analysis of information sources in references of the Wikipedia article "Digital signal" in English language version.
A digital representation can have only specific discrete values
A digital signal is a special form of discrete-time signal which is discrete in both time and amplitude, obtained by permitting each value (sample) of a discrete-time signal to acquire a finite set of values (quantization), assigning it a numerical symbol according to a code ... A digital signal is a sequence or list of numbers drawn from a finite set.
A digital representation can have only specific discrete values