User:Ryan Cooley/DigitalTransition

The account of this former contributor was not re-activated after the server upgrade of March 2022.

Scratch pad

Satellite communications, Terrestrial TV and radio. Everything is becoming digital.

There are numerous reasons for the switchover from analog to digital systems.

Digital modulation methods are much more efficient.

Analog modulation is device and function-specific, and generally consists of whatever signal is most conveniently created and utilized by the device in question. For audio, this consists of simply modulating the actual audio signal onto a higher frequency, and performing minimal filtering.

This allows for the cheapest device designs, since minimal signal conversion needs to be done. However, it results in the most inefficient use of limited RF bandwidth. Additionally, it doesn't allow any flexibility for the broadcasters, as all parameters are fixed.

Digital modulation allows for maximum spectrum efficiency, often 10× more efficient than the analog method it replaces. Digital modulation methods are also device and function agnostic. COFDM is used for everything from satellite TV signals (DVB-S), to dynamic wireless computer networks (IEEE 802.11g WiFi).

Digital modulation is also function agnostic, allowing for dynamic utilization of the available bandwidth. DAB, for example, allows broadcasters to select the bitrate required for each channel, so that a monaural voice broadcast need not use up as much bandwidth as a high quality stereo music broadcast.

In addition, the analog data being broadcast is rarely, if ever, compressed. The progress of digital processing, however, has led to extremely efficient digital compression methods for text, images, audio, video and any and all other common forms of digital data. Multimedia, in particular, can benefit from "lossy" compression, where a significant portion of the data, which humans are unable to perceive, can be entirely removed before lossless data compression, and before broadcast, vastly reducing the data size as much as 30:1.

Digital modulation also allows for substantial resistance to many common forms of RF interference, like electrical noise, multipath interference, signal fade, and the like.

Digital modulation allows for more controlled signals, requiring much smaller guard bands between channels to prevent inter-channel interference.