JVC 250 Glossary of Terms, Amorphous, Arc Lamp, Aspect Ratio, Bandwidth, Chrominance, Cold Mirror

Glossary

Glossary of Terms

Amorphous	Without definite form; not crystallized.
Arc Lamp	The high intensity light source in the Model 250
	projector. The Xenon Arc Lamp operates at high
	temperatures (160° to 200°) and produces
	dangerously intensive light with hazardous levels
	of ultraviolet and infrared radiation.
Aspect Ratio	The ratio of the picture width to picture height.
	The standard U.S. television aspect ratio is four
	units wide to three units high (4:3).
Bandwidth	Bandwidth is the difference between the lowest
	and highest frequencies transmitted or received. In
	digital formats it is measured in bits per second
	and in communications, it is measured in Hertz.
	Wider bandwidth provides more information or
	picture detail capability.
Chrominance	Abbreviated as “C”. The portion of the YPbPr
	and S-image signal that contains the color
	information signal.
Cold Mirror	Mirror that absorbs infrared light so that its
	reflection contains only “cold light” or light that
	does not transmit appreciable heat. Because of
	this absorption of infrared heat radiation, “cold
	mirrors” get quite hot.
Cross-member Assembly	Assembly attached to the main chassis that
	crosses over the top of the midsection of the
	projector. Used to mount the front and rear
	covers.
CRT (Cathode Ray Tube)	The Cathode Ray Tube is used as a display screen
	in televisions and computer monitors. Commonly
	referred to as the picture tube. The Model 250
	projector uses three CRTs.
Dichroic Mirrors	The white light of the xenon arc lamp is separated
	into red, green and blue by means of dichroic
	beamsplitters that reflect only one color and pass
	all others.

Model 250 Service Manual A-1