technical complexity of a video camera, it is
fundamentally simple. To understand clearly motion
video, you must be familiar with some key terms. These
terms will be seen commonly in all publications
pertaining to video.
KEY TERMS
AGC-Automatic gain control. Regulates the
volume of the audio or video light levels automatically
within a camcorder.
Analog-An analog signal that fluctuates exactly
like the original stimulus (examples, sweep second-
hand clock, phonograph player).
Ambient Sound-Background sound or “wild”
sound. Sound that surrounds the scene or location,
received by the microphone and recorded onto magnetic
tape.
Aspect Ratio-The ratio of the height to the width
of the film or television frame. Three units high to four
units wide (3:4).
Audio Track-The area of a videotape that is used
for recording audio information.
Beam Splitter-An optical device within a color
camera that splits the white light into three primary
colors: red, green, and blue.
Camcorder-A portable video camera with
videotape recorder (VTR) and a microphone attached to
form a single unit.
Capstan -An electrically driven roller that rotates
and transports the videotape past the recorder heads at
precise and fixed speeds.
CCD-Charged-coupled device, also called a chip.
A small, solid state (silicon resin) imaging device used
in a video camera instead of camera pickup tubes. Inside
the chip, image sensing elements translate the optical
image into a video signal.
Character Generator-An electronic device used
to create words or graphics that may be electronically
inserted or “keyed” over the video picture.
Color Bars-A color standard used by the television
industry for the alignment of cameras and videotape
recordings.
Component-The processing of RGB (red, green,
blue) channels as three separate channels.
Composite Signal (Y/C)-(Also called NTSC
signal) The video signal in which luminance “Y” (black
and white) and chrominance (red, green, blue) and sync
information are encoded into a single signal.
Control Track-The area of the videotape used for
recording the information necessary to synchronize the
all elements during playback.
Digital VTR-A videotape recorder that translates
and records the analog video signal in digital form.
Dub-Duplication of an electronic recording. Dub is
always one generation away from the original recording.
Dropout-A loss of part of the video signal, which
appears as white glitches. Caused by dirty VTR heads
or poor quality videotape.
Field-Scanning lines in one-half of one video or
television frame. There are two fields (one odd and one
even) in a frame. One field equals 262.5 scanning lines,
which create a total of 525 standard television lines or
one frame. Also known as the NTSC signal (U.S. TV
system).
Frame-The smallest unit in television or film, a
single picture. A complete scanning cycle of the two
fields occurs every 1/30 second. A frame equals 525
scan lines.
Gain-The level of amplification for a video or
audio signals. Increasing the video gain increases the
picture contrast.
Generation-The number of dubs or copies away
from the original recording. The greater the number of
generations, the greater the loss of picture quality.
Heads-A small assemble within an audio or video
recording system, which can erase, record or playback
the signal in electromagnetic impulses.
Helical Scan, or Helical VTR-(Also called slant
track). A videotape recording or a videotape recorder in
which the video signal is put on tape in a slanted,
diagonal way. Because the tape wraps around the head
drum in a spiral-like configuration, it is called helical.
Noise-Unwanted sounds or electrical interference
in a audio or video signal. In the audio track, there is a
hiss or humming sound. In the video picture the
interference appears as “snow.”
NTSC-National Television Standards Committee.
U.S. standards for television or video signal broad-
casting. Also known as the composite signal (Y/C).
Pickup Tube-The imaging device in a video
camera that converts light into electrical energy (video
signal).
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