Digital sampling
Digital sampling, PCM sampling, or just sampling is the process of representing a signal waveform as a series of numbers which represent the measurement of the sound's amplitude, taken at regular intervals. This process, also commonly referred to as PCM is widely used in modern audio and video systems, including television and telephone networks.
Strictly speaking, the process of sampling must be regarded as separate from the process of digitising. Sampling produces a series of values which may be represented in various ways - the output from the process can be a series of analog pulses (Pulse-height modulation) or a series of fixed amplitude pulses (Pulse position modulation or Pulse-width modulation. Most commonly though, the samples are represented by binary numbers, in a process known as PCM, an acronym for Pulse-code modulation, because they are then amenable to storage and processing in digital systems such as computers.