An analog signal is a sine wave. Like an ocean wave in constant motion, an analog signal continually changes over time. In fact, the term analog is actually derived from the word analogous because of the signal’s analogous relationship to the sine wave (Figure 11.1). Digital information, on the other hand, is fixed and absolute and does not change over time. When information is digitized, the data remains as it was originally recorded.
Video was originally developed as part of the analog world. Because the system was analog, it had the ease and advantages of fitting into the natural physical system. However, it also carried with it all the interference and noise problems. Noise is analog information just ...