| As this first decade of the 21st Century | | | | phenomenon. The process by which a digital |
| draws to a close, so also does the age of | | | | signal duplicates an analog quantity is |
| analog. When it comes to communications, | | | | called encoding, or just simply coding. |
| analog has served humanity long and well, but | | | | Encoding allows the digital representation of |
| the old technology is being phased out by | | | | analog quantities - an area of infinite |
| governments and manufacturers alike, and | | | | variability - by using a binary system that |
| within ten years, the old analog systems will | | | | creates an on-off switch for all those |
| likely be a technological footnote to | | | | variables (theoretically). This use of |
| history. Put simply, analog equipment cannot | | | | digital signals gives a major improvement in |
| compete with the capacity of digital and, as | | | | noise reduction. |
| a result of simple economics, it is destined | | | | |
| to dwindle away. Of course, analog systems | | | | Noise affects the inherent value of a signal, |
| made sense when first created, for analog | | | | whether it is digital or analog, but on an |
| signals are able to duplicate virtually any | | | | analog signal the noise has an impact on the |
| natural phenomena, such as sound or light, | | | | value of that signal, because increased |
| which are analog inherently because they are | | | | voltage over an analog signal creates |
| infinitely variable. | | | | distortion. When an analog signal is |
| | | | recorded, it is inevitable that noise is |
| With analog systems of communications, the | | | | recorded along with it. If it is then |
| biggest problem has always been noise. While | | | | re-recorded, the original noise is |
| analog offers the infinite variability that | | | | indistinguishable from the original signal, |
| replicates the natural state of sound or | | | | and becomes, effectively, part of the new |
| light, converting those phenomena into an | | | | signal. At each recording stage, extra noise |
| electrical signal and then back again into a | | | | will be introduced into the system and |
| sound or an image creates "noise." The term | | | | multiple copying of an analog signal |
| is used because it can literally produce | | | | ultimately results in an unacceptable loss of |
| noise in an audio system - the hiss or rumble | | | | quality, called generation loss. |
| that is heard in poor quality recordings. | | | | |
| Noise also shows itself in the grain or | | | | When a digital signal is recorded, it too |
| "snow" that can trouble a TV signal. Noise | | | | will include noise picked up within the |
| affects an electronic signal at every stage | | | | system. However, a digital signal is clearly |
| of the communications process, and its | | | | identifiable, despite any noise the signal |
| effects add up. | | | | picks up. At the root of the digital |
| | | | advantage is the fact that the signals in a |
| Although a digital signal cannot directly | | | | digital system do not have to be accurate. A |
| represent an analog quantity, everybody know | | | | voltage only needs to be readable as a one or |
| that a digital device like and Mp3 player | | | | a zero to be processed. Thus, digital |
| offers excellent quality duplication of | | | | communications signals offer possibilities |
| sound, which is, in fact, an analog | | | | which have no equivalent in analog systems. |