Grass Valley Performer-HD - Manual (Page 57)

Performer-HD Instruction Manual Glossary-3
dard Definition parallel digital video
employed within a device typically uses
two 10 bit buses operating at 13.5 MHz.
(2) For parallel interfaces between devices
using multi-pair cables (now obsolescent)
the two buses are combined for Standard
Definition video into one 27 MHz interface
(SMPTE 125M). The two buses remain sep-
arate for High Definition parallel interfaces
using multi-pair cables (SMPTE 274M).
Pixel
A picture element. A pixel is a digital sam-
ple of the color intensity values of a picture
at a single point.
PECL
Positive Emitter Coupled Logic
Progressive
Scanning every line of a video picture in
sequential order to create a complete pic-
ture. Each complete scan is a frame.
Reclocking
The process of clocking the data with a re-
generated clock.
Serial Digital Video
Passing video data bits in serial form (one
bit after another), along a single wire. High
Definition serial digital (1080i and 720p as
defined by SMPTE 292M) operates at 1.485
GHz (2 x 74.25 MHz x 10 bits). In compari-
son, Standard Definition serial digital vid-
eo (SMPTE 259M) operates at 270 MHz (2 x
13.5 MHz x 10 bits).
Serializer
A device that converts parallel digital in-
formation to serial.
Standard Definition Television (SDTV)
A digital television system with quality ap-
proximately equivalent to that of NTSC.
Sync
(1) General term for a synchronizing signal
or signal component. Digital systems gen-
erally employ an analog external timing
reference signal (such as color black or tri-
level sync) to synchronize different pieces
of equipment. Within the digital signal it-
self, however, synchronizing information
is carried by special digital codes inserted
at the beginning and end of each active
line.
(2) In analog television systems, sync is the
portion of the video signal which occurs
during blanking and is used to synchro-
nize the operation of cameras, monitors,
and other equipment. Horizontal sync oc-
curs within the blanking period in each
horizontal scanning line, and vertical sync
occurs within the vertical blanking period.
A color black signal is often used for syn-
chronizing different pieces of analog
equipment.
Television
An electric transmission and reception of
transient visual images, usually together
with associated sound. Television general-
ly involves the broadcast of information
from one location to many locations.
Tri-Level Sync
The synchronizing portion of the HDTV
signal, as defined in SMPTE 240M. Tri-lev-
el sync signals (which are analog) can be
used to synchronize different pieces of
HDTV equipment.
Video
An electric signal that carries transient vi-
sual images. Video generally involves the
movement of visual information from a
single source location to a single destina-
tion, or to a small number of destinations.
Many different types of analog and digital
video signals exist.