Ericsson SVP 2000, Справочное руководство, Страница: 168 / 196

Glossary
PAL Phase Alternating Line: A color TV broadcasting system where the
phase of the R-Y color-difference signal is inverted on every
alternate line to average out errors providing consistent color
reproduction.
PAT Program Association Table: Part of the MPEG-2 Program Specific
Information (PSI) data and is mandatory for MPEG-2 compliance.
The PAT points (maps) to the PMT.
PCM Pulse Code Modulation: A process in which a signal is sampled,
each sample is quantized independently of other samples, and the
resulting succession of quantized values is encoded into a digital
signal.
PCR Program Clock Reference: A time stamp in the transport stream
from which the Decoder timing is derived.
PDC Program Delivery Control: A Teletext service allowing simple
programming (i.e. VideoPlus) of VCR recording times. If the desired
program is rescheduled, PDC updates the programming information
in the VCR.
Pel Picture Element: Also known as a pixel. The smallest resolvable
rectangular area of an image either on a screen or stored in
memory. On-screen, pixels are made up of one or more dots of
color. Monochrome and grey-scale systems use one dot per pixel.
For grey-scale, the pixel is energized with different intensities,
creating a range from dark to light (a scale of 0-255 for an eight-bit
pixel). Color systems use a red, green and blue dot per pixel, each
of which is energized to different intensities, creating a range of
colors perceived as the mixture of these dots. If all three dots are
dark, the result is black. If all three dots are bright, the result is
white.
PES Packetized Elementary Stream: A sequential stream of data bytes
that has been converted from original elementary streams of audio
and video access units and transported as packets. Each PES
packet consists of a header and a payload of variable length and
subject to a maximum of 64 kbytes. A time stamp is provided by the
MPEG-2 systems layer to ensure correct synchronization between
related elementary streams at the Decoder.
PID Packet Identifier: the header on a packet in an elementary data
stream, which identifies that data stream. An MPEG-2 / DVB
standard.
PIN Personal Identification Number: A password used to control access
to programming and to set purchase limits. Each subscriber
household can activate several PINs and may use them to set
individual parental rating or spending limits for each family member.
Pixel PIX (picture) Element: The digital representation of the smallest
area of a television picture capable of being delineated by the
bit-stream. See PEL for more information.
pk-pk peak to peak: Measurement of a signal or waveform from its most
negative point to its most positive point.
EN/LZT 790 0046/1 R1A A-14