In order to understand the notion of digitizing information, it must first be understood that everything in nature, including the sounds and images one wishes to record or transmit, is originally analog. The second thing to be understood is that analog works very well. In fact, a first-generation analog recording can be a better representation of the original images than a first-generation digital recording. This is because digital is a coded approximation of analog. With enough bandwidth, a first-generation analog videotape recorder (VTR) can record the more "perfect" copy.

Binary Systems

Digital is a binary language represented by zeros (an "off" state) and ones (an "on" state), so the signal either exists ("on") or does not exist ("off"). Even with low signal power, if the transmitted digital signal is higher that the background noise level, a perfect picture and sound can be obtained—"on" is "on...