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Chapter 6: Appendix
75
“Contrast ratio”: The radio of the high light output level divided by the low light output level.
In theory, the contrast radio of the television system should be at least 100:1, if not 300:1.
In reality, there are several limitations. In the CRT, light from adjacent elements
contaminate the area of each element. Room ambient light will contaminate the light
emitted from the CRT. Well-controlled viewing conditions should yield a practical contrast
ratio of 30:1 to 50:1.
“DVI”: Digital Visual Interface. The digital video connectivity standard that was developed by
DDWG (Digital Display Work Group). This connection standard offers two different
connectors: one with 24 pins that handles digital video signals only, and one with 29 pins
that handles both digital and analog video.
“EDID”: Extended Display Identification Data – EDID is a data structure used to communicate
video display information, including native resolution and vertical interval refresh rate
requirements, to a source device. The source device will then output the optimal video
format for the display based on the provided EDID data, ensuring proper video image
quality. This communication takes place over the DDC – Display Data Channel.
“Ethernet”: A Local Area Network (LAN) standard officially known as IEEE 802.3. Ethernet
and other LAN technologies are used for interconnecting computers, printers, workstations,
terminals, servers, etc. within the same building or campus. Ethernet operates over twisted
pair and over coaxial cable at speeds starting at 10Mbps. For LAN interconnectivity,
Ethernet is physical link and data link protocol reflecting the two lowest layers of the OSI
Reference Model.
“Frame”: In interlaced video, a frame is one complete picture. A video frame is made up of
two fields, or two sets of interlaced lines. In a film, a frame is one still picture of a series
that makes up a motion picture.
“Gamma”: The light output of a CRT is not linear with respect to the voltage input. The
difference between what you should have and what is actually output is known as gamma.
“HDMI” - High – Definition Multimedia Interface: An interface used primarily in consumer
electronics for the transmission of uncompressed high definition video, up to 8 channels of
audio, and control signals, over a single cable. HDMI is the de facto standard for HDTV
displays, Blu-ray Disc players, and other HDTV electronics. Introduced in 2003, the HDMI
specification has gone through several revisions.
“HDSDI”: The high-definition version of SDI specified in SMPTE-292M. This signal standard
transmits audio and video with 10 bit depth and 4:2:2 color quantization over a single
coaxial cable with a data rate of 1.485 Gbit/second. Multiple video resolutions exists
including progressive 1280x720 and interlaced 1920x1080 resolution. Up to 32 audio
signals are carried in the ancillary data.
“JPEG” (Joint photographic Expects Group): Commonly used method of lossy compression
for photographic images using a discreet cosine transfer function. The degree of
compression can be adjusted, allowing a selectable tradeoff between storage size and
image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image
quality. Produces blocking artifacts.
“MPEG”: Motion Picture Expect Group. A standard committee under the auspices of the
International Standards Organization working on algorithm standards that allow digital
compression, storage and transmission of moving image information such as motion video,
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