Differential pulse-code modulation

Differential pulse-code modulation (DPCM) encodes changes between consecutive samples of a signal, rather than the signal's value directly (as done in pulse-code modulation). Decoding might thus be done by some manner of integrating DPCM samples over time. The input can be an analog signal or a digital signal. If the input is a continuous-time analog signal, it needs to be sampled to become a discrete-time signal.