Big Book OF AV Europe Edition Page 374 Appendix and Glossary

GLOSSARY 374 LCoS (Liquid Crystal on Silicon) A projection TV technology based on LCD. With LCoS, light is reflected from a mirror behind the LCD panel rather than passing through the panel. The control circuitry that switches the pixels on and off is embedded further down in the chip so it doesn't block the light, which improves brightness and contrast. This multilayered microdisplay design can be used in rear-projection TVs and projectors. TV makers use different names for their LCoS technologies. LED (Light Emitting Diode) An LED is a semiconductor diode that typically emits a single wavelength of light when an electric current passes through it. Different colors can be generated based on the material used; common colors include red, green, blue, and white. Letterbox Letterboxing means copying the widescreen format with aspect ratio of 16:9 to video format with aspect ratio of 4:3. The result of this process is that the full picture is presented only on the middle part of the screen, with black bars above and below it. Light Output Measures the amount of light produced by a video display and is an especially important spec for projectors. Expressed in lumens or ANSI lumens, with a higher number indicating greater light output, which results in a brighter picture. Line Level Also know as low-level, line level is an audio term referring to the signal before power amplification. In a system with separate pre-amp and power-amp, the pre- amp output is line level. CD players, VCRs, DVD players, laserdisc players etc., are connected in a system at line level, usually with shielded RCA type interconnects. Loudness A listener's auditory impression of the strength of a sound. The average deviation above and below the static value due to sound wave is called sound pressure. The energy expended during the sound wave vibration is called intensity and is measured in intensity units. Loudness is the physical resonance to sound pressure and intensity. Lumen The unit of measure for light output of a projector. Different manufacturers may rate their projectors' light output differently. Peak lumens is measured by illuminating an area of about 10% of the screen size in the center of the display. This measurement ignores the reduction in brightness at the sides and corners of the screen. The more conservative ANSI lumens (American National Standards Institute) specification is made by dividing the screen into 9 blocks, taking a reading in the center of each, and averaging the readings. This number is usually 20-25% lower than the peak lumen measurement. M Matrix A technique of storing more than one audio channel on a single channel. Dolby Surround is an example, where the center and surround channels are electronically extrapolated from the left and right channels of a stereo signal. This contrasts with today's discrete digital channels. Matrix Decoder Produces red, green, and blue from Y, R-Y, and B-Y. Matrix Switcher An electronic device with multiple inputs and outputs, the matrix allows any input to be connected to any one, several, or all of the outputs. Maximum Power Rating The maximum wattage that an audio component can deliver/handle as a brief burst. Most reputable manufacturers will provide both an RMS (continuous) and max power rating. Typically, the given value for the maximum power rating is twice to three times that of RMS. Midbass Mid frequency bass, usually frequencies just above the sub-bass range, from around 100 - 200Hz or so. Midrange The mid band of an audible signal, typically anywhere between 200Hz and 2kHz. Also refers to the drivers that specialize in these frequencies.

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