Learn in the textbookUnits of Information and the Digitization Process
DefinitionDigitization (デジタル化) is replacing analog information that changes continuously with separate, discrete numbers.
ExplanationDigital information is recorded as a sequence of numbers, so it hardly degrades even when copied or sent again and again, and a computer can calculate with it and edit it. Sound and similar information goes through sampling and quantization, and finally encoding, which writes each level number as a sequence of 0s and 1s, to become digital data.
AnalogyIt is like rebuilding a gentle slope as a staircase: once you record the position and height of each step as numbers, you can build the same shape again as many times as you like.
Memory hookDigit originally meant a finger, so picture counting on your fingers one by one: digitization turns information into values you can count.