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DVB-ASI: Asynchronous
Serial Interface as specified by DVB
standard
Asynchronous Serial Interface was
specified by DVB, dedicated at conveying
bit serial MPEG2 transport streams
over long distances, high noise tolerant
(typically for satellite applications,
for example). Using a 75 ohms coaxial
cable, ASI standard allows to interconnect
two devices more than 300 meters far
from each other, with data rate up
to 214 Mbps (line transmission rate
of 270 Mbps with 8B/10B data encoding).
Two functional modes of ASI do exist
: burst mode, or continuous mode.
In burst mode (also called packet
mode), a complete MPEG2 packet can
be sent at maximum rate (214 Mbps),
then transfer is paused until the
next packet of data is ready to be
transmitted. In continuous mode (also
called byte mode), data bytes are
spread out evenly in time, leading
to an instantaneous data rate approaching
the average data rate. ASI interface
is widely used by broadcasting professionals,
since it combines cost effective and
easy to use cabling, and large bandwidth.
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