Glossary-25
Appendices
Appendix.fm7/22/03
SVGA A type of video signal with a resolution of 800 (horizontal) × 600 (vertical) dots which is
used by IBM PC/AT-compatible computers.
S-Video A type of video signal which has the video brightness and colour signal information
separated, in order to provide better image quality. It refers to images which consist of two
independent signals: Y(luminance signal), and C (colour signal).
Sync.
(Synchronisation)
The signals output from computers have a specific frequency. Image quality will suffer if the
projector frequency and the computer frequency do not match. The process of matching the
phases of these signals (the relative position of the crests and troughs in the signal) is called
"synchronisation". If the signals are not synchronised, problems such as flickering,
blurriness and horizontal interference can occur.
Tracking The signals output from computers have a specific frequency. Image quality will suffer if the
projector frequency and the computer frequency do not match. The process of matching the
frequency of these signals (the number of crests in the signal) is called "tracking". If
tracking is not carried out correctly, wide vertical stripes will appear in the projected images.
VGA A type of video signal with a resolution of 640 (horizontal) × 480 (vertical) dots which is
used by IBM PC/AT-compatible computers.
XGA A type of video signal with a resolution of 1,024 (horizontal) × 768 (vertical) dots which is
used by IBM PC/AT-compatible computers.
YCbCr The carrier signal contained in the colour bar signal used in modern (NTSC) TV
transmissions. The name comes from the Y (luminance) signal and the CbCr (chroma
(colour)) signals.
YPbPr The carrier signal contained in the colour bar signal used in high-definition TV (HDTV)
transmissions. The name comes from the Y (luminance) signal and the PbPr (colour
difference) signals.
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