JVC 250 - Manual (Page 188)

Glossary
Model 250 Service Manual A-3
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.