Siemens CRT Brochure page 212

Glossary
Twisted Pair Cable
Is a type of balanced cable in which a pair of cables are twisted and
the signal is divided between them.
Two Speed Recorder
Is a domestic VCR which has two speeds of recording/playback, stan-
dard and long play. The long play mode doubles the recording time
of a standard tape.
Ultraviolet
Is electromagnetic radiation with a wavelength of less than 400 nm
and is not visible to the human eye.
Unbalanced Cable
Is a type of cable in which the ends of the shields are grounded to
different equipment with possibly varying ground potential. This
unbalanced set up can give rise to ground loop currents and EMI
induction.
UPS
Uninterruptible Power Supply stores electricity and supplies power to
a CCTV system during a power failure.
Usable Video
Is the minimum video signal specified in the camera data sheet to
generate an acceptable picture on the monitor. It is usually mea-
sured as a percentage of the full video.
Varifocal Lens
Is a type of manual zoom lens with a small zoom ratio (ranging
between 3.5 mm to 70 mm depending on brand). It is used when
the focal length of the lens needs to be fine tuned to meet the
requirements of the actual scene.
Video Head
An internal part of a VCR which rotates very rapidly and writes the
video signal on to the video tape during recording while reading the
video signal from the tape during playback.
Vertical Resolution
Is the number of horizontal lines which can be resolved in a picture.
It is limited by the television scanning method - NTSC, PAL etc.
Vertical Shift Register
Is a part of the interline transfer of a CCD chip , it is placed in
between every column of the pixels. At the end of each frame the
charge from the pixels are sent to the vertical shift register (VSR) and
then row by row to the horizontal shift register.
Vertical Streaking
This type of picture distortion occurs due to overloading of the pixels
in an interline transfer chip. It appears as vertical streaks above and
below the bright part of the picture.
VHS
Video Home System is a type of popular recording format used in
video cassette recorders.
© Siemens Building Technologies Group
Video Amplifier
Is used to boost the strength of a video signal.
Video Cassette Recorder
Is a device which can record (or playback) video and audio signals on
a magnetic tape housed in a cassette.
Video Distribution Amplifier
The video distribution amplifier is used not only to boost the
strength but also create multiple outputs of the video input signal.
Video Intercom
Is a door entry system which uses both audio and video to communi-
cate and/or control movement of people.
Video Monitoring
Is an application which uses video to monitor remote sites in any
part of the world. The video images are transmitted through the tele-
phone network.
Video Motion Detection
Is a means which can detect change in the pixelation or movement
in the picture and then generate an alarm.
Wattage
Is a unit of power measured in watts (W).
Wave Length
Is the distance travelled by an electro magnetic wave during one
cycle.
Wide Angle Lens
A type of lens which gives a wide view of the scene and has a magni-
fication ratio of less than 1.
Wide Dynamic Range
A camera with wide dynamic range is able to improve the image
quality. It corrects too bright and too dark areas of the scene.
Zoom Lens
A type of lens with a variable focal length ranging from wide angle to
telephoto.
Zoom Ratio
Is the ratio between the maximum and minimum focal length of a
zooms lens.
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