Quantisation (in signal processing) refers to the process of reducing a continuous signal to a set of discrete symbols or integer values. In general, a quantization operator can be represented as
where x is a real number, Q(x) an integer, and f(x) is an arbitary real-valued function that controls the 'quantization law' of the particular coder.
For example, in digital telephony, two popular quantization schemes are the 'A-law' and 'µ-law', each mapping an analog signal to an 8-bit digital value, but each with a different function f.
See also:
Quantization is also used, in quantum physics to describe the process by which a physical system exhibits quantized behavior, rather than continuous, or 'classical' behavior.