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Appendix C
Glossary
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OLED. Organic light-emitting diode; a graphical color display for use as television screens,
computer displays, portable system screens, and in advertising and information board
applications
Packet Identifier (PID). A unique integer value used to associate elementary streams of a
program in a single or multi-program transport stream.
Packet. A packet consists of a header followed by a number of contiguous bytes from an
elementary data stream. It is a layer in the system coding syntax.
Packetized Elementary Stream (PES). The data structure used to carry elementary stream
data. The packets consist of a header followed by payload data, and a stream is a series of
packets which form an elementary stream and have a single stream identification.
PAL. Phase Alternation Line; the standard color television system in many European and
other countries.
Passive Looping. Video and audio signals routed through components, even if power is
removed. Signals are not amplified or processed, maintaining transparency.
Pedestal Level. An offset used in a video system to separate the active video from the
blanking level by maintaining the black level above the blanking level by a small amount.
Pixel. A Picture cell or Picture element representing one sample of picture information, such
as an individual sample of R, G, B, luminance or chrominance.
Pollution Degree. A measurement of the foreign materials such as conductive dust, gas,
and moisture between the internal areas of the product and the outside environment.
Pollution Degrees are 1,2 3, and 4.

Pollution Degree 1 describes conditions where no pollution occurs or only dry,
nonconductive pollution occurs. This is normal for equipment located in clean rooms.
The pollution classified under Pollution Degree 1 has no environmental influence.

Pollution Degree 2 describes conditions where dry, nonconductive pollution occurs. This
is normal in an office environment. Temporary conductivity caused by condensation
may occur when the unit is not in service.

Pollution Degree 3 describes conditions where conductive pollution occurs, or dry,
nonconductive pollution occurs due to condensation. Rooms that cannot maintain the
moisture or temperature fall into this category. The location can only protect from
outside weather conditions such as direct sunlight, rain, snow, and wind. Industrial
areas can fall under Pollution Degree 3.

Pollution Degree 4 describes pollution that generates persistent conductivity through
conductive dust, rain, or snow. Pollution Degree 4 is for outdoor locations.
Preset. Refers to establishing any condition prior to use on the Program output. This term is
used in reference to wipe patterns and is often interchanged with Preview.
Preview. The video output channel used to view the intended Program results prior to the
execution of the next transition.
PRO Audio. A transmitted audio channel for talent cueing via Interrupt Foldback (IFB) to
ENG vans and remote applications. Some demodulators support PRO audio monitoring.