KRAMER: SIMPLE CREATIVE TECHNOLOGY
Overview
2
3 Overview
The VS-28 8 Channel Video Audio Standby is an eight channel standby
switcher for composite video and stereo audio signals. Each of the eight
channels is a discreet 2x1 standby switcher for composite video using BNC
connectors, and stereo audio using detachable screw terminal connectors.
The VS-28 8 Channel Video Audio Standby is much like having eight Kramer
VS-24N’s in a single two-space rack mountable enclosure. Each 2x1 channel
is designed to automatically switch to the second input any time the primary
video signal is interrupted. At the same time, a front-panel LED illuminates,
and an extra relay is activated which can be used to trigger an alarm. If the
primary signal reappears, the individual channel will switch back to input
one. Each channel can be forced to select input 2 by using a short to ground
available on detachable screw terminal connectors. When the power of the
VS-28 8 Channel Video Audio Standby is removed or turned off, input one
will be routed to the output.
Achieving the best performance means:
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Connecting only good quality connection cables, thus avoiding
interference, deterioration in signal quality due to poor matching, and elevated
noise levels (often associated with low quality cables)
•
Avoiding interference from neighboring electrical appliances and
positioning your VS-28 away from excessive sunlight, moisture and dust
3.1 Several Words on Video/Audio Switchers
A video/audio switcher usually switches between several sources and one or
more acceptors. A switcher that allows several inputs to be connected to
several outputs simultaneously is called a matrix switcher. Switchers may be
of the electronic or mechanic type. Most matrices are of the active electronic
type, with many crosspoints.
Vertical Interval Switching, often used in video, assures that the transition
from one video source to the other (like switching between two Genlocked
cameras) is smooth and without interference. The switching and changeover
is done during the blanked vertical interval period, where the transition is
hidden from the eyes.
Vertical Interval switching is needed when recording or transmitting a video
program involving several video sources, as in live broadcast, to assure
“clean”, undisturbed picture transitions. The switched sources should be
genlocked.
Matrices and switchers may be RS-232 controlled. RS-232 control is a way of
remotely controlling a video or audio device using a personal computer with a
