It is classified with
satellite, cable television, electric-wave in terms of transmitting
media of broadcast, and also classified with FTA(Free To Air),
air on charge in terms of the type of broadcast provider. On
charge is classified again with CI(Common Interface) and CAS(Conditional
Access System) in terms of access restriction system.
STB for satellite broadcast receives
electric wave sent from BS and CS with parabola antenna, and
tunes it. Presented the functional structure of STB for satellite
broadcast below.
It is classified with one-way STB
and two-way interactive STB. Observing each other, they are
as follows. As a reference, we presented a block figure of one-way
set top box below. two-way STB is a one-way STB attached by
data transmitter, and generally transmits data in 64kbps after
connected in phone line. The use of two-way is confirmation
of communications line, viewers research data, viewer confirmation,
and self-diagnosis result, so on. But in future, it will extend
to approval in television shopping, Internet connection, and
information supply by viewer participation.
Digital electric-wave broadcast,
starting from the States and England, is to be spread worldwide
in future. Considering viewer needs accustomed to electric-wave
broadcast, STB for digital electric-wave seems to prevail for
the time being. Also, most semi-conductor vendors are regarding
it as one of the most prospect applications. Especially, semi-conductor
manufacturers try to provide solution for system LSI for STB
by enforcing core library.
Core library contains CPU core, MPEG-2 video decoder, MPEG-2
voice decoder, disk rambler, interfaces(IEEE 1284, IEEE 1394),
Smart Card Interface.
Video/voice Decoder performs decompressing
functions of received MPEG2 compressed data, video and voice
process is composed of Graphic Over Lay, Graphic Processor,
Encoder, and also supports presentation and conversation process.
Digital STB is keeping on continuous development from early
simple, receiving centric broadcasting products to in-house
multimedia complex and a core platform of home networking
having PVR, DVB-MHP, and networking functions built-in.
Korean
Digital
Broadcasting
