LAWO V_pro8, Руководство по установке и эксплуатации

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V_pro8 Manual V1.0/2 107
Glossary
dB deciBel
A unit of transmission giving the ratio of two powers. Used in audio to
represent changes in signal level.
The number of bels is the logarithm to the base 10 of the ratio of the two
powers. One decibel equals one tenth of a bel.
dBu dBu is used to describe audio signal levels within the analogue domain, and
is a measure of absolute voltage level based on 0dBu = 0.775 Volts (RMS).
dBu is often used to indicate nominal broadcast operating levels. For
example, in the EBU normal broadcasting level = +6dBu.
dBFS dB Full Scale
dBFS is used to describe audio signal levels within the digital domain.
0dBFS describes the system’s internal clipping point; this is the maximum
level which may be handled by the system without signal distortion. For
example, your system may be set for +18dBu = 0dBFS. If your normal
broadcast level is +6dBu then this leaves an operating headroom of 12dB.
Frame A video frame consists of all the information required to reproduce a still
picture image. Each frame is made up of several horizontal picture
elements known as lines. To form a moving picture, several frames are
scanned per second, creating a frame rate.
Interlaced scanning systems (i) capture every odd line, and then every even
line on alternate scans of the picture frame; this creates two fields per video
frame. Progressive scanning (p) is smoother than interlaced scanning, as
all lines are captured on every scan of the picture frame.
Common frame rates used in television standards include 25 frames per
second (fps) and 29.97 fps. In NTSC television, 525 interlaced horizontal
lines are scanned at 29.97 frames per second. In the PAL system, 625
interlaced horizontal lines are scanned at 25 frames per second.
When you apply a video delay of one frame, you delay the picture by a
single, still image. The time this represents, in milliseconds, depends on
the frame rate.
Frame Synchroniser A device used to match the timing of an incoming video source to the timing
of a reference signal. The frame synchroniser essentially takes a picture of
each frame of incoming video and then immediately outputs it with the
correct synchronisation to match that of the reference signal. The result is
to align the incoming video signal and create a stable image. An
unsynchronised signal can produce picture flicker.
Gain Adjusting the gain of a signal results in a change in the perceived level or
amplitude. An increase in gain (positive values) results in amplification and
a reduction in gain (negative values) in attenuation.
HD High Definition.
This terms refers to video signals of a higher resolution than Standard
Definition (SD). HD video may be transmitted in various standards including
1080p, 1080i and 720p, where "p" and "i" stand for progressive and
interlaced scan. Please see
Technical Data for supported video standards.
Interlaced Scan See Frame.