JVC 250 Lumen, Luminance, Noise, Overscanning, Raster, Resolution, Retrace, RGB Red, Green, Blue

	Glossary
Lumen	A unit of measure of the flow, or rate of emission,
	of light measured with a Light Meter. An
	ordinary wax candle generates 13 lumens while a
	100-watt bulb generates 1,200 lumens.
Luminance	Abbreviated as "Y." The portion of the YPbPr
	and S-image signal that contains the black and
	white information, which affects brightness.
Noise	An undesirable electrical interference of a signal.
Overscanning	Displaying less than the complete area of an
	image to a viewer (i.e., scanning beyond the
	visible area). All TV sets are overscanned at least
	slightly, so that viewers do not see blanking.
Raster	The area illuminated by the scan lines on a CRT.
Resolution	The degree of sharpness of a displayed or printed
	character or image. The amount of detail in a
	picture. On a display screen, resolution is
	expressed as the number of horizontal dots
	(columns) by the number of vertical lines (rows).
	For example, a 680 x 400 resolution means 680
	dots across each of 400 lines.
Retrace	The blanked-out line traced by the scanning beam
	of a picture tube as it travels from the end of any
	horizontal line to the beginning of either the next
	horizontal line or field. The beam is turned "off"
	during retrace.
RGB (Red, Green, Blue)	Refers to the method of recording and generating
	colors in a video system. On a television or color
	monitor, colors are displayed as varying
	intensities of red, green and blue dots. When red,
	green and blue are all turned on high, white is
	produced. When all dots are turned off, the base
	color of the screen appears.
S-VHS	A high band video recording process for VHS that
	increases picture quality and resolution capability.
	S-VHS tape machines use a special output
	terminal that allows separate output of luminance
	(Y) and chrominance (C) picture information to
	monitors equipped with S-image inputs.

Model 250 Service Manual A-3