<s>
A	O
DTV	B-Device
receiver	I-Device
is	O
a	O
set-top	O
box	O
that	O
permits	O
the	O
reception	O
of	O
digital	B-Application
television	I-Application
.	O
</s>
<s>
The	O
DTV	B-Device
receiver	I-Device
is	O
a	O
vital	O
link	O
in	O
the	O
chain	O
of	O
television	O
system	O
.	O
</s>
<s>
The	O
main	O
features	O
of	O
a	O
DTV	B-Device
receiver	I-Device
may	O
be	O
classified	O
as	O
follows	O
:	O
</s>
<s>
The	O
tuner	O
in	O
the	O
box	O
receives	O
a	O
digital	O
signal	O
from	O
a	O
cable	O
,	O
a	O
satellite	B-Application
,	O
or	O
terrestrial	O
network	O
and	O
isolates	O
a	O
particular	O
channel	O
.	O
</s>
<s>
As	O
the	O
architecture	O
of	O
a	O
DTV	B-Device
receiver	I-Device
can	O
vary	O
in	O
function	O
of	O
the	O
network	O
operator	O
or	O
the	O
set-box	O
manufacturer	O
,	O
we	O
have	O
chosen	O
to	O
divide	O
the	O
physical	O
components	O
into	O
the	O
following	O
categories	O
:	O
</s>
<s>
Buses	O
are	O
used	O
to	O
carry	O
the	O
digital	B-Application
TV	I-Application
information	O
between	O
the	O
hardware	O
components	O
.	O
</s>
<s>
The	O
ATSC	B-Device
tuner	I-Device
module	O
is	O
available	O
for	O
accessing	O
QAM-	O
,	O
OFDM	O
,	O
and	O
QPSK-based	O
networks	O
.	O
</s>
<s>
The	O
technology	O
used	O
in	O
DTV	O
television	O
is	O
MPEG-2	B-Algorithm
.	O
</s>
<s>
A	O
DTV	B-Device
receiver	I-Device
will	O
normally	O
contain	O
three	O
separate	O
decoders	O
for	O
converting	O
the	O
digital	O
bit-stream	O
back	O
into	O
a	O
format	O
that	O
can	O
be	O
heard	O
and	O
viewed	O
by	O
the	O
subscriber	O
.	O
</s>
<s>
Different	O
audio	O
modes	O
are	O
usually	O
supported	O
by	O
the	O
DTV	B-Device
receiver	I-Device
:	O
mono	O
and	O
dual	O
channel	O
,	O
stereo	O
,	O
and	O
joint	O
stereo	O
.	O
</s>
<s>
The	O
CPU	O
,	O
like	O
in	O
a	O
desktop	O
PC	O
,	O
is	O
the	O
brain	O
of	O
the	O
DTV	B-Device
receiver	I-Device
.	O
</s>
<s>
As	O
a	O
computer	O
,	O
a	O
DTV	B-Device
receiver	I-Device
needs	O
memory	O
to	O
store	O
and	O
manipulates	O
instructions	O
.	O
</s>
