The conversion of a set of digital data from a given sampling rate to a higher one. In digital audio for instance, audio data on a CD is sampled at 44.1 KHz, meaning that there are 44100 "chunks" (or samples) of data representing the sound for each second. Upsampling this data would convert it to, say, 88.2 KHz, by interpolating an additional sample between each of the existing ones. Commonly used in high end audio as a feature for advanced DACs.