aliasing

A phenomenon that occurs when different analog continuous signals overlap and become indistinguishable. If the sampling of the analog waveform is too infrequent (less than half the highest frequency present), the digitally encoded signal cannot reliably be decoded faithfully. Rather, it can be reconstructed as an alias of the true signal. Aliasing is a major concern in the digital encoding of analog audio and video signals. Aliasing in video signals results in artifacts in video images that can manifest as jagged blockings or a tiling effect. See also analog, digital, encoding, PCM, and waveform.