Digital Recording

Digital recording itself produces truer audio and video, and the systems developed for playing them also help eliminate interference. The most familiar audio system, the compact disc, uses a laser beam player to read the digital information coded on the disc. Digital audio tape (DAT) became available in the late 1980s. It uses magnetic tape and a specialized DAT recorder with a microprocessor to convert audio signals to digital data during recording and to switch the data back to analog signals for playback. DAT systems are available to the average consumer but are used extensively by professionals. Digital compact cassette (DCC) recorders can play both DAT tapes and the analog tape cassettes that are more common.

Video systems parallel the audio methods. Compact discs for video recordings were initially considered impractical because of the complexities of carrying both images and sound, so larger diameter laser discs that also use a laser beam player to decode information on the discs were one system of playing back video. Laser discs (also called videodiscs) store audio information in digital form and video as analog data. Video tapes in Beta and VHS formats (both analog forms) were easier to mass produce at smaller cost. Another portion of the video problem was that video could be recorded on compact discs, but the level of fidelity of the disc was better than any television could reproduce. The video recording industry had to wait for televisions to catch up. In the late 1990s, high-density television (HDTV) became available, and the digital video disc (DVD) and DVD players rapidly became more popular in anticipation of better television technology. The DVD (also called the digital versatile disc) can accommodate all the sound and light needed for a Star Wars movie, for example, because it holds almost five billion bytes of data and may soon hold over eight billion data bytes; a typical CD-ROM for home computer use stores only 650 million bytes. Digital cameras were also introduced in 1997, the same year that DVD players were first widely sold. Improvement of HDTV was given a push by government; a phase-out of nondigital TV signals is to occur over 10 years (beginning in 1998) to be replaced by the digital images from satellites, digital network broadcasts, and DVD sources. Cable systems are also converting to digital signals.

Advances in the home computer industry are closely linked with audio and video digital recording systems. First, home computers have increasingly included audio and video playback systems. Second, the mergers of audio and video giants with Internet firms have shown that all these services may soon be provided directly to our homes through one cable, phone line, or other shared system. And third, the technology for putting more and better information on a compact disc has made the disc the leading medium for sound recordings (as the compact disc), video (in the form of DVDs), and information (CDROMs and recordable and erasable CDs for data, sound, and video). Erasable and recordable compact discs are called CD-Es and CD-Rs, respectively; following their introduction in the late 1990s, the equipment for using them (with home sound systems and computers) quickly became affordable. The DVD also has a close relative for computer data storage called the DVD disc drive that replaces the CD-ROM in some personal computers (PCs). Eventually, technology may produce a single type of disc that can be encoded and played back by computer, audio recorder/players, and video recorder/players (depending, of course, on the information on the disc).