Analog means representative of. If something is analogous, then it is a copy or representative of the original. In communications and electronics work, the term analog is used to mean a particular type of circuitry or manner of dealing with voltage and current. A good analog signal is absent distortion when compared to the original. A microphone converts sound waves (acoustical energy) into electrical energy voltage and current. A speaker converts electrical energy into acoustical energy. Distortion of any kind along the path between source and destination is undesirable technically and may not be commercially acceptable to the viewer or listener. Electrically or electronically, an analog waveform is a representation of voltage at any given instant or over a period of time. It can be stable or varying in amplitude. The polarity may be constant or reverse in regular or irregular intervals. In practical broadcast engineering, analog is a label to characterize NTSC, PAL, SECAM video, and non-digitized audio signals. In today s digital world it s important to recognize and remember the following two things: (1) content or the signals representing the content must be digitized or present in digital form to be carried on digital transport media; and (2) video is structured, while its counterpart, audio, is relatively unstructured. Program content audio and video signals in analog form and digital media mix about as well as oil and water.

If a signal is in analog form and needs to be carried...