Digital to analog conversion is what lets us play back the growing masses of digital information. A CD is a gleaming plastic disk, but not worth the $14.95 price until those bits have been turned back to music by playing them through a chip at 44 thousand per second or so. It also lets digital information move along imperfect communications lines. Modems are modulator/demodulator devices, D/A on the one end and A/D on the other and switching as the need arises. This kind of modulation has to be perfect, or it might as well not have happened at all.

This file created with Hypertype 2.2 by Simon St.Laurent