Big Book OF AV Europe Edition Page 375 Appendix and Glossary

GLOSSARY 375 Microdisplay A general term covering several different technologies used in digital rear-projection TVs and projectors. These displays produce large images; the micro refers to the postage stamp-sized image chips that create the images. Microdisplay types include DLP, LCD, and LCoS. For a comparison of rear-projection microdisplay types, and details on how each technology works. MPEG (Moving Picture Experts Group) The organization charged with developing video and audio encoding standards. On the video front, consumers are most likely to encounter the MPEG-2 and MPEG- 4 compression formats, or codecs. These formats are capable of producing very high quality video by employing an adaptive, variable bitrate process that can allocate more bits for complex scenes involving a lot of motion, while reducing the bits in static scenes. MPEG-2: Used for over-the-air digital television broadcasts, standard DVDs, some Blu-Ray disc and HD DVD discs, and small-dish satellite TV (DIRECTV and Dish). MPEG-4: This newer format is more efficient than MPEG-2, meaning it can deliver the same picture quality as MPEG-2 using a lower bitrate. Some Blu- Ray discs and HD DVDs, and newer DIRECTV and Dish satellite gear use MPEG-4. N Noise An undesirable signal that is unintentionally added to a picture or sound signal. Nominal In home audio there are two main uses of this term: 1. Nominal Power Rating- minimum amount of power recommended for a speaker. 2. Nominal Impedance- theoretically the minimum impedance a speaker will present to the amplifier. Nonresonant Materials that don't vibrate much or absorb vibrations, which can affect sound reproduction; materials often included in the construction of a loudspeaker. NTSC (National Television Systems Committee) National Television Systems Committee is the organization that develops technical standards for both black-and-white and color television. The term is also used to refer to the video-transmission standard used in the western hemisphere, Japan, and other Asian countries. O Octave An octave is a doubling or halving of frequency. 20Hz to 40Hz is often considered the bottom octave, 40Hz to 80Hz is the bass octave. 80Hz to 160Hz is the upper bass octave, etc. Octave Bands Sounds that contain energy over a wide range of frequencies are divided into sections called bands. A common standard division is in 10 octave bands identified by their censer frequencies 31.5, 63, 125, 250, 500, 1000, 2000 and 4000Hz. Ohm The unit used to measure electrical resistance. (The word ohm comes from German physicist Georg Simon Ohm, 1787-1854.) An 8-ohm loudspeaker presents a good level of resistance and will be compatible with most modern amplifiers. OLED (Organic Light Emitting Diode) OLED is an up-and-coming display technology that can be used to create flat-panel TVs. An OLED panel employs a series of organic thin films placed between two transparent electrodes. An electric current causes these ilms to produce a bright light. A thin-film transistor layer contains the circuitry to turn each individual pixel on and off to form an image. The organic process is called electrophosphorescence, which means the display is self- illuminating, requiring no backlight. OLED panels are thinner and lighter than current plasma or LCD HDTVs, and have lower power consumption. Output The sound level produced by a loudspeaker. Overload A condition in which a system is given too high of an input level. A common cause of distortion or product failure.

Previous Page
Next Page