<s>
Advanced	B-Device
Television	I-Device
Systems	I-Device
Committee	I-Device
(	O
ATSC	B-Device
)	O
standards	O
are	O
an	O
American	O
set	O
of	O
standards	O
for	O
digital	B-Application
television	I-Application
transmission	O
over	O
terrestrial	O
,	O
cable	O
and	O
satellite	O
networks	O
.	O
</s>
<s>
Several	O
former	O
NTSC	O
users	O
,	O
such	O
as	O
Japan	O
,	O
have	O
not	O
used	O
ATSC	B-Device
during	O
their	O
digital	B-Application
television	I-Application
transition	O
,	O
because	O
they	O
adopted	O
other	O
systems	O
such	O
as	O
ISDB	B-Protocol
developed	O
by	O
Japan	O
,	O
and	O
DVB	B-Application
developed	O
in	O
Europe	O
,	O
for	O
example	O
.	O
</s>
<s>
The	O
ATSC	B-Device
standards	I-Device
were	O
developed	O
in	O
the	O
early	O
1990s	O
by	O
the	O
Grand	B-Device
Alliance	I-Device
,	O
a	O
consortium	O
of	O
electronics	O
and	O
telecommunications	O
companies	O
that	O
assembled	O
to	O
develop	O
a	O
specification	O
for	O
what	O
is	O
now	O
known	O
as	O
HDTV	B-Device
.	O
</s>
<s>
The	O
standard	O
is	O
now	O
administered	O
by	O
the	O
Advanced	B-Device
Television	I-Device
Systems	I-Device
Committee	I-Device
.	O
</s>
<s>
Key	O
among	O
these	O
is	O
the	O
8VSB	B-Device
modulation	B-Application
system	O
used	O
for	O
over-the-air	O
broadcasts	O
.	O
</s>
<s>
ATSC	B-Device
technology	O
was	O
primarily	O
developed	O
with	O
patent	O
contributions	O
from	O
LG	O
Electronics	O
,	O
which	O
holds	O
most	O
of	O
the	O
patents	O
for	O
the	O
ATSC	B-Device
standard	I-Device
.	O
</s>
<s>
ATSC	B-Device
includes	O
two	O
primary	O
high	O
definition	O
video	O
formats	O
,	O
1080i	O
and	O
720p	O
.	O
</s>
<s>
It	O
also	O
includes	O
standard-definition	B-Device
formats	O
,	O
although	O
initially	O
only	O
HDTV	B-Device
services	O
were	O
launched	O
in	O
the	O
digital	O
format	O
.	O
</s>
<s>
ATSC	B-Device
can	O
carry	O
multiple	O
channels	O
of	O
information	O
on	O
a	O
single	O
stream	O
,	O
and	O
it	O
is	O
common	O
for	O
there	O
to	O
be	O
a	O
single	O
high-definition	O
signal	O
and	O
several	O
standard-definition	B-Device
signals	O
carried	O
on	O
a	O
single	O
6MHz	O
(	O
former	O
NTSC	O
)	O
channel	O
allocation	O
.	O
</s>
<s>
The	O
high-definition	B-Device
television	I-Device
standards	O
defined	O
by	O
the	O
ATSC	B-Device
produce	O
widescreen	O
16:9	O
images	O
up	O
to	O
1920×1080	O
pixels	B-Algorithm
in	O
sizemore	O
than	O
six	O
times	O
the	O
display	B-General_Concept
resolution	I-General_Concept
of	O
the	O
earlier	O
standard	O
.	O
</s>
<s>
The	O
reduced	O
bandwidth	B-Algorithm
requirements	O
of	O
lower-resolution	O
images	O
allow	O
up	O
to	O
six	O
standard-definition	B-Device
"	O
subchannels	O
"	O
to	O
be	O
broadcast	O
on	O
a	O
single	O
6MHz	O
TV	O
channel	O
.	O
</s>
<s>
ATSC	B-Device
standards	I-Device
are	O
marked	O
A/x	O
(	O
x	O
is	O
the	O
standard	O
number	O
)	O
and	O
can	O
be	O
downloaded	O
for	O
free	O
from	O
the	O
ATSC	B-Device
's	O
website	O
at	O
ATSC.org	O
.	O
</s>
<s>
ATSC	B-Device
Standard	I-Device
A/53	B-Device
,	O
which	O
implemented	O
the	O
system	O
developed	O
by	O
the	O
Grand	B-Device
Alliance	I-Device
,	O
was	O
published	O
in	O
1995	O
;	O
the	O
standard	O
was	O
adopted	O
by	O
the	O
Federal	O
Communications	O
Commission	O
in	O
the	O
United	O
States	O
in	O
1996	O
.	O
</s>
<s>
ATSC	B-Device
Standard	I-Device
A/72	O
was	O
approved	O
in	O
2008	O
and	O
introduces	O
H.264/AVC	B-Application
video	O
coding	O
to	O
the	O
ATSC	B-Device
system	I-Device
.	O
</s>
<s>
ATSC	B-Device
supports	O
5.1-channel	O
surround	O
sound	O
using	O
Dolby	O
Digital	O
's	O
AC-3	O
format	O
.	O
</s>
<s>
Many	O
aspects	O
of	O
ATSC	B-Device
are	O
patented	O
,	O
including	O
elements	O
of	O
the	O
MPEG	O
video	O
coding	O
,	O
the	O
AC-3	O
audio	O
coding	O
,	O
and	O
the	O
8VSB	B-Device
modulation	B-Application
.	O
</s>
<s>
The	O
cost	O
of	O
patent	O
licensing	O
,	O
estimated	O
at	O
up	O
to	O
per	O
digital	B-Application
TV	I-Application
receiver	O
,	O
had	O
prompted	O
complaints	O
by	O
manufacturers	O
.	O
</s>
<s>
As	O
with	O
other	O
systems	O
,	O
ATSC	B-Device
depends	O
on	O
numerous	O
interwoven	O
standards	O
,	O
e.g.	O
,	O
the	O
EIA-708	B-Device
standard	O
for	O
digital	O
closed	O
captioning	O
,	O
leading	O
to	O
variations	O
in	O
implementation	O
.	O
</s>
<s>
ATSC	B-Device
replaced	O
much	O
of	O
the	O
analog	O
NTSC	O
television	O
system	O
in	O
the	O
United	O
States	O
on	O
June	O
12	O
,	O
2009	O
,	O
on	O
August	O
31	O
,	O
2011	O
in	O
Canada	O
,	O
on	O
December	O
31	O
,	O
2012	O
in	O
South	O
Korea	O
,	O
and	O
on	O
December	O
31	O
,	O
2015	O
in	O
Mexico	O
.	O
</s>
<s>
Broadcasters	O
who	O
used	O
ATSC	B-Device
and	O
wanted	O
to	O
retain	O
an	O
analog	O
signal	O
were	O
temporarily	O
forced	O
to	O
broadcast	O
on	O
two	O
separate	O
channels	O
,	O
as	O
the	O
ATSC	B-Device
system	I-Device
requires	O
the	O
use	O
of	O
an	O
entire	O
separate	O
channel	O
.	O
</s>
<s>
Channel	O
numbers	O
in	O
ATSC	B-Device
do	O
not	O
correspond	O
to	O
RF	O
frequency	O
ranges	O
,	O
as	O
they	O
did	O
with	O
analog	O
television	O
.	O
</s>
<s>
Instead	O
,	O
virtual	B-Protocol
channels	I-Protocol
,	O
sent	O
as	O
part	O
of	O
the	O
metadata	O
along	O
with	O
the	O
program(s )	O
,	O
allow	O
channel	O
numbers	O
to	O
be	O
remapped	O
from	O
their	O
physical	O
RF	O
channel	O
to	O
any	O
other	O
number	O
1	O
to	O
99	O
,	O
so	O
that	O
ATSC	B-Device
stations	O
can	O
either	O
be	O
associated	O
with	O
the	O
related	O
NTSC	O
channel	O
numbers	O
,	O
or	O
all	O
stations	O
on	O
a	O
network	O
can	O
use	O
the	O
same	O
number	O
.	O
</s>
<s>
There	O
is	O
also	O
a	O
standard	O
for	O
distributed	O
transmission	O
systems	O
(	O
DTx	B-Device
)	O
,	O
a	O
form	O
of	O
single-frequency	B-Device
network	I-Device
which	O
allows	O
for	O
the	O
synchronised	O
operation	O
of	O
multiple	O
on-channel	O
booster	O
stations	O
.	O
</s>
<s>
Dolby	O
Digital	O
AC-3	O
is	O
used	O
as	O
the	O
audio	B-Algorithm
codec	I-Algorithm
,	O
though	O
it	O
was	O
standardized	O
as	O
A/52	O
by	O
the	O
ATSC	B-Device
.	O
</s>
<s>
In	O
contrast	O
,	O
Japanese	O
ISDB	B-Protocol
HDTV	B-Device
broadcasts	O
use	O
MPEG	O
's	O
Advanced	B-Application
Audio	I-Application
Coding	I-Application
(	O
AAC	O
)	O
as	O
the	O
audio	B-Algorithm
codec	I-Algorithm
,	O
which	O
also	O
allows	O
5.1	O
audio	O
output	O
.	O
</s>
<s>
DVB	B-Application
(	O
see	O
below	O
)	O
allows	O
both	O
.	O
</s>
<s>
MPEG-2	B-Algorithm
audio	O
was	O
a	O
contender	O
for	O
the	O
ATSC	B-Device
standard	I-Device
during	O
the	O
DTV	B-Application
"	O
Grand	B-Device
Alliance	I-Device
"	O
shootout	O
,	O
but	O
lost	O
out	O
to	O
Dolby	O
AC-3	O
.	O
</s>
<s>
The	O
Grand	B-Device
Alliance	I-Device
issued	O
a	O
statement	O
finding	O
the	O
MPEG-2	B-Algorithm
system	O
to	O
be	O
"	O
essentially	O
equivalent	O
"	O
to	O
Dolby	O
,	O
but	O
only	O
after	O
the	O
Dolby	O
selection	O
had	O
been	O
made	O
.	O
</s>
<s>
Later	O
,	O
a	O
story	O
emerged	O
that	O
MIT	O
had	O
entered	O
into	O
an	O
agreement	O
with	O
Dolby	O
whereupon	O
the	O
university	O
would	O
be	O
awarded	O
a	O
large	O
sum	O
of	O
money	O
if	O
the	O
MPEG-2	B-Algorithm
system	O
was	O
rejected	O
.	O
</s>
<s>
The	O
ATSC	B-Device
system	I-Device
supports	O
a	O
number	O
of	O
different	O
display	B-General_Concept
resolutions	I-General_Concept
,	O
aspect	B-Device
ratios	I-Device
,	O
and	O
frame	O
rates	O
.	O
</s>
<s>
The	O
formats	O
are	O
listed	O
here	O
by	O
resolution	O
,	O
form	O
of	O
scanning	O
(	O
progressive	B-Device
or	O
interlaced	O
)	O
,	O
and	O
number	O
of	O
frames	O
(	O
or	O
fields	O
)	O
per	O
second	O
(	O
see	O
also	O
the	O
TV	O
resolution	O
overview	O
at	O
the	O
end	O
of	O
this	O
article	O
)	O
.	O
</s>
<s>
For	O
transport	O
,	O
ATSC	B-Device
uses	O
the	O
MPEG	O
systems	O
specification	O
,	O
known	O
as	O
an	O
MPEG	O
transport	O
stream	O
,	O
to	O
encapsulate	O
data	O
,	O
subject	O
to	O
certain	O
constraints	O
.	O
</s>
<s>
ATSC	B-Device
uses	O
188-byte	O
MPEG	O
transport	O
stream	O
packets	O
to	O
carry	O
data	O
.	O
</s>
<s>
Before	O
decoding	O
of	O
audio	O
and	O
video	O
takes	O
place	O
,	O
the	O
receiver	O
must	O
demodulate	B-Device
and	O
apply	O
error	B-Error_Name
correction	I-Error_Name
to	O
the	O
signal	O
.	O
</s>
<s>
There	O
are	O
four	O
basic	O
display	O
sizes	O
for	O
ATSC	B-Device
,	O
generally	O
known	O
by	O
referring	O
to	O
the	O
number	O
of	O
lines	O
of	O
the	O
picture	O
height	O
.	O
</s>
<s>
The	O
third	O
size	O
is	O
HDTV	B-Device
images	O
that	O
have	O
720	O
scan	O
lines	O
in	O
height	O
and	O
are	O
1280	O
pixels	B-Algorithm
wide	O
.	O
</s>
<s>
The	O
largest	O
size	O
has	O
1080	O
lines	O
high	O
and	O
1920	O
pixels	B-Algorithm
wide	O
.	O
</s>
<s>
1080-line	O
video	O
is	O
actually	O
encoded	O
with	O
1920×1088	O
pixel	B-Algorithm
frames	O
,	O
but	O
the	O
last	O
eight	O
lines	O
are	O
discarded	O
prior	O
to	O
display	O
.	O
</s>
<s>
This	O
is	O
due	O
to	O
a	O
restriction	O
of	O
the	O
MPEG-2	B-Algorithm
video	O
format	O
,	O
which	O
requires	O
the	O
height	O
of	O
the	O
picture	O
in	O
luma	O
samples	O
(	O
i.e.	O
</s>
<s>
pixels	B-Algorithm
)	O
to	O
be	O
divisible	O
by	O
16	O
.	O
</s>
<s>
The	O
lower	O
resolutions	O
can	O
operate	O
either	O
in	O
progressive	B-Device
scan	I-Device
or	O
interlaced	O
mode	O
,	O
but	O
not	O
the	O
largest	O
picture	O
sizes	O
.	O
</s>
<s>
The	O
1080-line	O
system	O
does	O
not	O
support	O
progressive	B-Device
images	O
at	O
the	O
highest	O
frame	O
rates	O
of	O
50	O
,	O
59.94	O
or	O
60	O
frames	O
per	O
second	O
,	O
because	O
such	O
technology	O
was	O
seen	O
as	O
too	O
advanced	O
at	O
the	O
time	O
.	O
</s>
<s>
The	O
standard	O
also	O
requires	O
720-line	O
video	O
be	O
progressive	B-Device
scan	I-Device
,	O
since	O
that	O
provides	O
better	O
picture	O
quality	O
than	O
interlaced	O
scan	O
at	O
a	O
given	O
frame	O
rate	O
,	O
and	O
there	O
was	O
no	O
legacy	O
use	O
of	O
interlaced	O
scan	O
for	O
that	O
format	O
.	O
</s>
<s>
A	O
terrestrial	O
(	O
over-the-air	O
)	O
transmission	O
carries	O
19.39	O
megabits	O
of	O
data	O
per	O
second	O
(	O
a	O
fluctuating	O
bandwidth	B-Algorithm
of	O
about	O
18.3Mbit/s	O
left	O
after	O
overhead	O
such	O
as	O
error	B-Error_Name
correction	I-Error_Name
,	O
program	O
guide	O
,	O
closed	O
captioning	O
,	O
etc	O
.	O
</s>
<s>
)	O
,	O
compared	O
to	O
a	O
maximum	O
possible	O
MPEG-2	B-Algorithm
bitrate	O
of	O
10.08Mbit/s	O
(	O
7Mbit/s	O
typical	O
)	O
allowed	O
in	O
the	O
DVD	O
standard	O
and	O
48Mbit/s	O
(	O
36Mbit/s	O
typical	O
)	O
allowed	O
in	O
the	O
Blu-ray	O
disc	O
standard	O
.	O
</s>
<s>
Although	O
the	O
ATSC	B-Device
A/53	B-Device
standard	O
limits	O
MPEG-2	B-Algorithm
transmission	O
to	O
the	O
formats	O
listed	O
below	O
(	O
with	O
integer	O
frame	O
rates	O
paired	O
with	O
1000/1001	O
-rate	O
versions	O
)	O
,	O
the	O
U.S.	O
Federal	O
Communications	O
Commission	O
declined	O
to	O
mandate	O
that	O
television	O
stations	O
obey	O
this	O
part	O
of	O
the	O
ATSC	B-Device
's	O
standard	O
.	O
</s>
<s>
In	O
theory	O
,	O
television	O
stations	O
in	O
the	O
U.S.	O
are	O
free	O
to	O
choose	O
any	O
resolution	O
,	O
aspect	B-Device
ratio	I-Device
,	O
and	O
frame/field	O
rate	O
,	O
within	O
the	O
limits	O
of	O
Main	O
Profile	O
@	O
High	O
Level	O
.	O
</s>
<s>
Many	O
stations	O
do	O
go	O
outside	O
the	O
bounds	O
of	O
the	O
ATSC	B-Device
specification	O
by	O
using	O
other	O
resolutions	O
–	O
for	O
example	O
,	O
352	O
x	O
480	O
or	O
720	O
x	O
480	O
.	O
</s>
<s>
"	O
EDTV	O
"	O
displays	O
can	O
reproduce	O
progressive	B-Device
scan	I-Device
content	O
and	O
frequently	O
have	O
a	O
16:9	O
wide	O
screen	O
format	O
.	O
</s>
<s>
Such	O
resolutions	O
are	O
704×480	O
or	O
720×480	O
in	O
NTSC	O
and	O
720×576	O
in	O
PAL	O
,	O
allowing	O
60	O
progressive	B-Device
frames	O
per	O
second	O
in	O
NTSC	O
or	O
50	O
in	O
PAL	O
.	O
</s>
<s>
ATSC	B-Device
also	O
supports	O
PAL	O
frame	O
rates	O
and	O
resolutions	O
which	O
are	O
defined	O
in	O
ATSC	B-Device
A/63	O
standard	O
.	O
</s>
<s>
The	O
ATSC	B-Device
A/53	B-Device
specification	O
imposes	O
certain	O
constraints	O
on	O
MPEG-2	B-Algorithm
video	B-Application
stream	I-Application
:	O
</s>
<s>
The	O
maximum	O
bit	O
rate	O
value	O
in	O
the	O
sequence	O
header	O
of	O
the	O
MPEG-2	B-Algorithm
video	B-Application
stream	I-Application
is	O
19.4Mbit/s	O
for	O
broadcast	O
television	O
,	O
and	O
38.8Mbit/s	O
for	O
the	O
"	O
high	O
data	O
rate	O
"	O
mode	O
(	O
e.g.	O
,	O
cable	O
television	O
)	O
.	O
</s>
<s>
The	O
actual	O
MPEG-2	B-Algorithm
video	O
bit	O
rate	O
will	O
be	O
lower	O
,	O
since	O
the	O
MPEG-2	B-Algorithm
video	B-Application
stream	I-Application
must	O
fit	O
inside	O
a	O
transport	O
stream	O
.	O
</s>
<s>
The	O
amount	O
of	O
MPEG-2	B-Algorithm
stream	O
buffer	O
required	O
at	O
the	O
decoder	O
(	O
the	O
vbv_buffer_size_value	O
)	O
must	O
be	O
less	O
than	O
or	O
equal	O
to	O
999,424	O
bytes	O
.	O
</s>
<s>
The	O
ATSC	B-Device
specification	O
and	O
MPEG-2	B-Algorithm
allow	O
the	O
use	O
of	O
progressive	B-Device
frames	O
coded	O
within	O
an	O
interlaced	O
video	O
sequence	O
.	O
</s>
<s>
For	O
example	O
,	O
NBC	O
stations	O
transmit	O
a	O
1080i60	O
video	O
sequence	O
,	O
meaning	O
the	O
formal	O
output	O
of	O
the	O
MPEG-2	B-Algorithm
decoding	O
process	O
is	O
sixty	O
540-line	O
fields	O
per	O
second	O
.	O
</s>
<s>
However	O
,	O
for	O
prime-time	O
television	O
shows	O
,	O
those	O
60	O
fields	O
can	O
be	O
coded	O
using	O
24	O
progressive	B-Device
frames	O
as	O
a	O
base	O
–	O
actually	O
,	O
an	O
1080p24	O
video	B-Application
stream	I-Application
(	O
a	O
sequence	O
of	O
24	O
progressive	B-Device
frames	O
per	O
second	O
)	O
is	O
transmitted	O
,	O
and	O
MPEG-2	B-Algorithm
metadata	O
instructs	O
the	O
decoder	O
to	O
interlace	O
these	O
fields	O
and	O
perform	O
3:2	O
pulldown	O
before	O
display	O
,	O
as	O
in	O
soft	O
telecine	O
.	O
</s>
<s>
The	O
ATSC	B-Device
specification	O
also	O
allows	O
1080p30	O
and	O
1080p24	O
MPEG-2	B-Algorithm
sequences	O
,	O
however	O
they	O
are	O
not	O
used	O
in	O
practice	O
,	O
because	O
broadcasters	O
want	O
to	O
be	O
able	O
to	O
switch	O
between	O
60Hz	O
interlaced	O
(	O
news	O
)	O
,	O
30Hz	O
progressive	B-Device
or	O
PsF	O
(	O
soap	O
operas	O
)	O
,	O
and	O
24Hz	O
progressive	B-Device
(	O
prime-time	O
)	O
content	O
without	O
ending	O
the	O
1080i60	O
MPEG-2	B-Algorithm
sequence	O
.	O
</s>
<s>
The	O
1080-line	O
formats	O
are	O
encoded	O
with	O
1920	O
×	O
1088	O
pixel	B-Algorithm
luma	O
matrices	O
and	O
960	O
×	O
540	O
chroma	O
matrices	O
,	O
but	O
the	O
last	O
8	O
lines	O
are	O
discarded	O
by	O
the	O
MPEG-2	B-Algorithm
decoding	O
and	O
display	O
process	O
.	O
</s>
<s>
In	O
July	O
2008	O
,	O
ATSC	B-Device
was	O
updated	O
to	O
support	O
the	O
ITU-T	B-Application
H.264	I-Application
video	O
codec	O
.	O
</s>
<s>
The	O
new	O
standards	O
support	O
1080p	O
at	O
50	O
,	O
59.94	O
and	O
60	O
frames	O
per	O
second	O
;	O
such	O
frame	O
rates	O
require	O
H.264/AVC	B-Application
High	O
Profile	O
Level	O
4.2	O
,	O
while	O
standard	O
HDTV	B-Device
frame	O
rates	O
only	O
require	O
Levels	O
3.2	O
and	O
4	O
,	O
and	O
SDTV	B-Device
frame	O
rates	O
require	O
Levels	O
3	O
and	O
3.1	O
.	O
</s>
<s>
It	O
may	O
contain	O
a	O
number	O
of	O
streams	O
of	O
audio	O
or	O
video	O
content	O
multiplexed	B-Architecture
within	O
the	O
transport	O
stream	O
.	O
</s>
<s>
Transport	O
streams	O
are	O
designed	O
with	O
synchronization	O
and	O
recovery	O
in	O
mind	O
for	O
potentially	O
lossy	O
distribution	O
(	O
such	O
as	O
over-the-air	O
ATSC	B-Device
broadcast	I-Device
)	O
in	O
order	O
to	O
continue	O
a	O
media	O
stream	O
with	O
minimal	O
interruption	O
in	O
the	O
face	O
of	O
data	O
loss	O
in	O
transmission	O
.	O
</s>
<s>
When	O
an	O
over-the-air	O
ATSC	B-Device
signal	O
is	O
captured	O
to	O
a	O
file	O
via	O
hardware/software	O
the	O
resulting	O
file	O
is	O
often	O
in	O
a	O
.TS	O
file	O
format	O
.	O
</s>
<s>
ATSC	B-Device
signals	O
are	O
designed	O
to	O
use	O
the	O
same	O
6MHz	O
bandwidth	B-Algorithm
as	O
analog	O
NTSC	O
television	O
channels	O
(	O
the	O
interference	O
requirements	O
of	O
A/53	B-Device
DTV	B-Application
standards	O
with	O
adjacent	O
NTSC	O
or	O
other	O
DTV	B-Application
channels	O
are	O
very	O
strict	O
)	O
.	O
</s>
<s>
Once	O
the	O
digital	O
video	O
and	O
audio	O
signals	O
have	O
been	O
compressed	O
and	O
multiplexed	B-Architecture
,	O
the	O
transport	O
stream	O
can	O
be	O
modulated	B-Application
in	O
different	O
ways	O
depending	O
on	O
the	O
method	O
of	O
transmission	O
.	O
</s>
<s>
Terrestrial	O
(	O
local	O
)	O
broadcasters	O
use	O
8VSB	B-Device
modulation	B-Application
that	O
can	O
transfer	O
at	O
a	O
maximum	O
rate	O
of	O
19.39Mbit/s	O
,	O
sufficient	O
to	O
carry	O
several	O
video	O
and	O
audio	O
programs	O
and	O
metadata	O
.	O
</s>
<s>
Cable	O
television	O
stations	O
can	O
generally	O
operate	O
at	O
a	O
higher	O
signal-to-noise	O
ratio	O
and	O
can	O
use	O
either	O
the	O
16VSB	B-Device
as	O
defined	O
in	O
ATSC	B-Device
or	O
the	O
256-QAM	B-Device
defined	O
in	O
SCTE	O
,	O
to	O
achieve	O
a	O
throughput	O
of	O
38.78Mbit/s	O
,	O
using	O
the	O
same	O
6MHz	O
channel	O
.	O
</s>
<s>
The	O
proposals	O
for	O
modulation	B-Application
schemes	O
for	O
digital	B-Application
television	I-Application
were	O
developed	O
when	O
cable	O
operators	O
carried	O
standard-resolution	O
video	O
as	O
uncompressed	O
analog	O
signals	O
.	O
</s>
<s>
In	O
recent	O
years	O
,	O
cable	O
operators	O
have	O
become	O
accustomed	O
to	O
compressing	O
standard-resolution	O
video	O
for	O
digital	B-Device
cable	I-Device
systems	O
,	O
making	O
it	O
harder	O
to	O
find	O
duplicate	O
6MHz	O
channels	O
for	O
local	O
broadcasters	O
on	O
uncompressed	O
"	O
basic	O
"	O
cable	O
.	O
</s>
<s>
The	O
Canadian	O
Radio-television	O
and	O
Telecommunications	O
Commission	O
in	O
Canada	O
does	O
not	O
have	O
similar	O
rules	O
in	O
force	O
with	O
respect	O
to	O
carrying	O
ATSC	B-Device
signals	O
.	O
</s>
<s>
However	O
,	O
cable	O
operators	O
have	O
still	O
been	O
slow	O
to	O
add	O
ATSC	B-Device
channels	O
to	O
their	O
lineups	O
for	O
legal	O
,	O
regulatory	O
,	O
and	O
plant	O
&	O
equipment	O
related	O
reasons	O
.	O
</s>
<s>
One	O
key	O
technical	O
and	O
regulatory	O
issue	O
is	O
the	O
modulation	B-Application
scheme	O
used	O
on	O
the	O
cable	O
:	O
cable	O
operators	O
in	O
the	O
U.S.	O
(	O
and	O
to	O
a	O
lesser	O
extent	O
Canada	O
)	O
can	O
determine	O
their	O
own	O
method	O
of	O
modulation	B-Application
for	O
their	O
plants	O
.	O
</s>
<s>
Multiple	O
standards	O
bodies	O
exist	O
in	O
the	O
industry	O
:	O
the	O
SCTE	O
defined	O
256-QAM	B-Device
as	O
a	O
modulation	B-Application
scheme	O
for	O
cable	O
in	O
a	O
cable	O
industry	O
standard	O
,	O
.	O
</s>
<s>
Consequently	O
,	O
most	O
U.S.	O
and	O
Canadian	O
cable	O
operators	O
seeking	O
additional	O
capacity	O
on	O
the	O
cable	O
system	O
have	O
moved	O
to	O
256-QAM	B-Device
from	O
the	O
64-QAM	B-Device
modulation	B-Application
used	O
in	O
their	O
plant	O
,	O
in	O
preference	O
to	O
the	O
16VSB	B-Device
standard	O
originally	O
proposed	O
by	O
ATSC	B-Device
.	O
</s>
<s>
Over	O
time	O
256-QAM	B-Device
is	O
expected	O
to	O
be	O
included	O
in	O
the	O
ATSC	B-Device
standard	I-Device
.	O
</s>
<s>
There	O
is	O
also	O
a	O
standard	O
for	O
transmitting	O
ATSC	B-Device
via	O
satellite	O
;	O
however	O
,	O
this	O
is	O
only	O
used	O
by	O
TV	O
networks	O
.	O
</s>
<s>
Very	O
few	O
teleports	O
outside	O
the	O
U.S.	O
support	O
the	O
ATSC	B-Device
satellite	O
transmission	O
standard	O
,	O
but	O
teleport	O
support	O
for	O
the	O
standard	O
is	O
improving	O
.	O
</s>
<s>
The	O
ATSC	B-Device
satellite	O
transmission	O
system	O
is	O
not	O
used	O
for	O
direct-broadcast	O
satellite	O
systems	O
;	O
in	O
the	O
U.S.	O
and	O
Canada	O
these	O
have	O
long	O
used	O
either	O
DVB-S	O
(	O
in	O
standard	O
or	O
modified	O
form	O
)	O
or	O
a	O
proprietary	O
system	O
such	O
as	O
DSS	B-Device
or	O
DigiCipher	B-Device
2	I-Device
.	O
</s>
<s>
ATSC	B-Device
coexists	O
with	O
the	O
DVB-T	O
standard	O
,	O
and	O
with	O
ISDB-T	O
.	O
A	O
similar	O
standard	O
called	O
ADTB-T	O
was	O
developed	O
for	O
use	O
as	O
part	O
of	O
China	O
's	O
new	O
DMB-T/H	O
dual	O
standard	O
.	O
</s>
<s>
While	O
China	O
has	O
officially	O
chosen	O
a	O
dual	O
standard	O
,	O
there	O
is	O
no	O
requirement	O
that	O
a	O
receiver	O
work	O
with	O
both	O
standards	O
and	O
there	O
is	O
no	O
support	O
for	O
the	O
ADTB	O
modulation	B-Application
from	O
broadcasters	O
or	O
equipment	O
and	O
receiver	O
manufacturers	O
.	O
</s>
<s>
For	O
compatibility	O
with	O
material	O
from	O
various	O
regions	O
and	O
sources	O
,	O
ATSC	B-Device
supports	O
the	O
480i	O
video	O
format	O
used	O
in	O
the	O
NTSC	O
analog	O
system	O
(	O
480	O
lines	O
,	O
approximately	O
60	O
fields	O
or	O
30	O
frames	O
per	O
second	O
)	O
,	O
576i	O
formats	O
used	O
in	O
most	O
PAL	O
regions	O
(	O
576	O
lines	O
,	O
50	O
fields	O
or	O
25	O
frames	O
per	O
second	O
)	O
,	O
and	O
24	O
frames-per-second	O
formats	O
used	O
in	O
film	O
.	O
</s>
<s>
While	O
the	O
ATSC	B-Device
system	I-Device
has	O
been	O
criticized	O
as	O
being	O
complicated	O
and	O
expensive	O
to	O
implement	O
and	O
use	O
,	O
both	O
broadcasting	O
and	O
receiving	O
equipment	O
are	O
now	O
comparable	O
in	O
cost	O
with	O
that	O
of	O
DVB	B-Application
.	O
</s>
<s>
The	O
ATSC	B-Device
signal	O
is	O
more	O
susceptible	O
to	O
changes	O
in	O
radio	O
propagation	O
conditions	O
than	O
DVB-T	O
and	O
ISDB-T	O
.	O
</s>
<s>
It	O
also	O
lacks	O
true	O
hierarchical	B-Protocol
modulation	I-Protocol
,	O
which	O
would	O
allow	O
the	O
SDTV	B-Device
part	O
of	O
an	O
HDTV	B-Device
signal	O
(	O
or	O
the	O
audio	O
portion	O
of	O
a	O
television	O
program	O
)	O
to	O
be	O
received	O
uninterrupted	O
even	O
in	O
fringe	O
areas	O
where	O
signal	O
strength	O
is	O
low	O
.	O
</s>
<s>
For	O
this	O
reason	O
,	O
an	O
additional	O
modulation	B-Application
mode	O
,	O
enhanced-VSB	O
(	O
E-VSB	B-Device
)	O
has	O
been	O
introduced	O
,	O
allowing	O
for	O
a	O
similar	O
benefit	O
.	O
</s>
<s>
In	O
spite	O
of	O
ATSC	B-Device
's	O
fixed	O
transmission	O
mode	O
,	O
it	O
is	O
still	O
a	O
robust	O
signal	O
under	O
various	O
conditions	O
.	O
</s>
<s>
8VSB	B-Device
was	O
chosen	O
over	O
COFDM	B-Protocol
in	O
part	O
because	O
many	O
areas	O
are	O
rural	O
and	O
have	O
a	O
much	O
lower	O
population	O
density	O
,	O
thereby	O
requiring	O
larger	O
transmitters	O
and	O
resulting	O
in	O
large	O
fringe	O
areas	O
.	O
</s>
<s>
In	O
these	O
areas	O
,	O
8VSB	B-Device
was	O
shown	O
to	O
perform	O
better	O
than	O
other	O
systems	O
.	O
</s>
<s>
COFDM	B-Protocol
is	O
used	O
in	O
both	O
DVB-T	O
and	O
ISDB-T	O
,	O
and	O
for	O
1seg	B-Device
,	O
as	O
well	O
as	O
DVB-H	B-Protocol
and	O
HD	O
Radio	O
in	O
the	O
United	O
States	O
.	O
</s>
<s>
In	O
metropolitan	O
areas	O
,	O
where	O
population	O
density	O
is	O
highest	O
,	O
COFDM	B-Protocol
is	O
said	O
to	O
be	O
better	O
at	O
handling	O
multipath	O
propagation	O
.	O
</s>
<s>
While	O
ATSC	B-Device
is	O
also	O
incapable	O
of	O
true	O
single-frequency	B-Device
network	I-Device
(	O
SFN	O
)	O
operation	O
,	O
the	O
distributed	O
transmission	O
mode	O
,	O
using	O
multiple	O
synchronized	O
on-channel	O
transmitters	O
,	O
has	O
been	O
shown	O
to	O
improve	O
reception	O
under	O
similar	O
conditions	O
.	O
</s>
<s>
Thus	O
,	O
it	O
may	O
not	O
require	O
more	O
spectrum	O
allocation	O
than	O
DVB-T	O
using	O
SFNs	O
.	O
</s>
<s>
A	O
comparison	O
study	O
found	O
that	O
ISDB-T	O
and	O
DVB-T	O
performed	O
similarly	O
,	O
and	O
that	O
both	O
were	O
outperformed	O
by	O
DVB-T2	B-Protocol
.	O
</s>
<s>
Mobile	O
reception	O
of	O
digital	O
stations	O
using	O
ATSC	B-Device
has	O
,	O
until	O
2008	O
,	O
been	O
difficult	O
to	O
impossible	O
,	O
especially	O
when	O
moving	O
at	O
vehicular	O
speeds	O
.	O
</s>
<s>
To	O
overcome	O
this	O
,	O
there	O
are	O
several	O
proposed	O
systems	O
that	O
report	O
improved	O
mobile	O
reception	O
:	O
Samsung/Rhode	O
&	O
Schwarz	O
's	O
A-VSB	B-Device
,	O
Harris/LG	O
'	O
s	O
MPH	B-Device
,	O
and	O
a	O
recent	O
proposal	O
from	O
Thomson/Micronas	O
;	O
all	O
of	O
these	O
systems	O
have	O
been	O
submitted	O
as	O
candidates	O
for	O
a	O
new	O
ATSC	B-Device
standard	I-Device
,	O
ATSC-M/H	B-Device
.	O
</s>
<s>
After	O
one	O
year	O
of	O
standardization	O
,	O
the	O
solution	O
merged	O
between	O
Samsung	B-Application
's	O
AVSB	O
and	O
LGE	O
's	O
MPH	B-Device
technology	O
has	O
been	O
adopted	O
and	O
would	O
have	O
been	O
deployed	O
in	O
2009	O
.	O
</s>
<s>
This	O
is	O
in	O
addition	O
to	O
other	O
standards	O
like	O
the	O
now-defunct	O
MediaFLO	B-Device
,	O
and	O
worldwide	O
open	O
standards	O
such	O
as	O
DVB-H	B-Protocol
and	O
T-DMB	O
.	O
</s>
<s>
Like	O
DVB-H	B-Protocol
and	O
ISDB	B-Protocol
1seg	B-Device
,	O
the	O
proposed	O
ATSC	B-Device
mobile	I-Device
standards	O
are	O
backward-compatible	B-General_Concept
with	O
existing	O
tuners	O
,	O
despite	O
being	O
added	O
to	O
the	O
standard	O
well	O
after	O
the	O
original	O
standard	O
was	O
in	O
wide	O
use	O
.	O
</s>
<s>
ATSC	B-Device
2.0	O
was	O
a	O
planned	O
major	O
new	O
revision	O
of	O
the	O
standard	O
which	O
would	O
have	O
been	O
backward	B-General_Concept
compatible	I-General_Concept
with	O
ATSC	B-Device
1.0	I-Device
.	O
</s>
<s>
Other	O
features	O
were	O
to	O
have	O
included	O
advanced	O
video	O
compression	O
,	O
audience	O
measurement	O
,	O
targeted	O
advertising	O
,	O
enhanced	O
programming	O
guides	O
,	O
video	B-Application
on	I-Application
demand	I-Application
services	I-Application
,	O
and	O
the	O
ability	O
to	O
store	O
information	O
on	O
new	O
receivers	O
,	O
including	O
Non-realtime	O
(	O
NRT	O
)	O
content	O
.	O
</s>
<s>
However	O
,	O
ATSC	B-Device
2.0	O
was	O
never	O
actually	O
launched	O
,	O
as	O
it	O
was	O
essentially	O
outdated	O
before	O
it	O
could	O
be	O
launched	O
.	O
</s>
<s>
All	O
of	O
the	O
changes	O
that	O
were	O
a	O
part	O
of	O
the	O
ATSC	B-Device
2.0	O
revision	O
were	O
adopted	O
into	O
ATSC	B-Device
3.0	O
.	O
</s>
<s>
ATSC	B-Device
3.0	O
will	O
provide	O
even	O
more	O
services	O
to	O
the	O
viewer	O
and	O
increased	O
bandwidth	B-Algorithm
efficiency	O
and	O
compression	O
performance	O
,	O
which	O
requires	O
breaking	O
backwards	B-General_Concept
compatibility	I-General_Concept
with	O
the	O
current	O
version	O
.	O
</s>
<s>
On	O
November	O
17	O
,	O
2017	O
,	O
the	O
FCC	O
voted	O
3	O
–	O
2	O
in	O
favor	O
of	O
authorizing	O
voluntary	O
deployments	O
of	O
ATSC	B-Device
3.0	O
,	O
and	O
issued	O
a	O
Report	O
and	O
Order	O
to	O
that	O
effect	O
.	O
</s>
<s>
ATSC	B-Device
3.0	O
broadcasts	O
and	O
receivers	O
are	O
expected	O
to	O
emerge	O
within	O
the	O
next	O
decade	O
.	O
</s>
<s>
LG	O
Electronics	O
tested	O
the	O
standard	O
with	O
4K	B-Device
on	O
February	O
23	O
,	O
2016	O
.	O
</s>
<s>
With	O
the	O
test	O
considered	O
a	O
success	O
,	O
South	O
Korea	O
announced	O
that	O
ATSC	B-Device
3.0	O
broadcasts	O
would	O
start	O
in	O
February	O
2017	O
.	O
</s>
<s>
On	O
March	O
28	O
,	O
2016	O
,	O
the	O
Bootstrap	O
component	O
of	O
ATSC	B-Device
3.0	O
(	O
System	O
Discovery	O
and	O
Signalling	O
)	O
was	O
upgraded	O
from	O
candidate	O
standard	O
to	O
finalized	O
standard	O
.	O
</s>
<s>
On	O
June	O
29	O
,	O
2016	O
,	O
NBC	O
affiliate	O
WRAL-TV	O
in	O
Raleigh	O
,	O
North	O
Carolina	O
,	O
a	O
station	O
known	O
for	O
its	O
pioneering	O
roles	O
in	O
testing	O
the	O
original	O
DTV	B-Application
standards	O
,	O
launched	O
an	O
experimental	O
ATSC	B-Device
3.0	O
channel	O
carrying	O
the	O
station	O
's	O
programming	O
in	O
1080p	O
,	O
as	O
well	O
as	O
a	O
4K	B-Device
demo	O
loop	O
.	O
</s>
<s>
ATSC	B-Device
3.0	O
allows	O
4K	B-Architecture
UHD	I-Architecture
transmission	O
,	O
including	O
high-dynamic-range	B-Application
television	I-Application
(	O
HDR-TV	B-Application
)	O
,	O
wide	O
color	O
gamut	O
(	O
WCG	O
)	O
,	O
and	O
high	O
frame	O
rate	O
(	O
HFR	O
)	O
.	O
</s>
<s>
ATSC	B-Device
3.0	O
allows	O
the	O
same	O
aerial	O
to	O
receive	O
more	O
channels	O
with	O
better	O
quality	O
.	O
</s>
<s>
On	O
December	O
14	O
,	O
2011	O
,	O
the	O
Bahamas	O
 '	O
national	O
public	O
broadcaster	O
ZNS-TV	O
announced	O
that	O
it	O
would	O
adopt	O
ATSC	B-Device
,	O
in	O
line	O
with	O
the	O
United	O
States	O
and	O
its	O
territories	O
.	O
</s>
<s>
adopted	O
ATSC	B-Device
,	O
with	O
full-power	O
analog	O
stations	O
in	O
specified	O
"	O
mandatory	O
markets	O
"	O
(	O
which	O
included	O
provincial	O
capitals	O
,	O
and	O
cities	O
with	O
a	O
population	O
of	O
300,000	O
or	O
higher	O
)	O
shutting	O
down	O
on	O
August	O
31	O
,	O
2011	O
.	O
</s>
<s>
Will	O
convert	O
to	O
ATSC	B-Device
3.0	O
instead	O
of	O
1.0	O
.	O
</s>
<s>
began	O
converting	O
to	O
ATSC	B-Device
in	O
2013	O
;	O
a	O
full	O
transition	O
was	O
scheduled	O
for	O
December	O
31	O
,	O
2015	O
,	O
but	O
due	O
to	O
technical	O
and	O
economic	O
issues	O
for	O
some	O
transmitters	O
,	O
the	O
full	O
transition	O
was	O
extended	O
to	O
December	O
31	O
,	O
2016	O
.	O
</s>
<s>
will	O
convert	O
to	O
ATSC	B-Device
3.0	O
instead	O
of	O
ATSC	B-Device
1.0	I-Device
.	O
</s>
<s>
Suriname	O
has	O
undergone	O
transitioning	O
from	O
analogue	O
NTSC	O
broadcasts	O
to	O
digital	O
ATSC	B-Device
broadcasts	I-Device
.	O
</s>
<s>
Channel	O
ATV	O
started	O
with	O
ATSC	B-Device
broadcasts	I-Device
in	O
the	O
Paramaribo	O
area	O
in	O
June	O
2014	O
,	O
which	O
was	O
followed	O
by	O
ATSC	B-Device
broadcasts	I-Device
from	O
stations	O
in	O
Brokopondo	O
,	O
Wageningen	O
and	O
Albina	O
.	O
</s>
<s>
In	O
2016	O
all	O
channels	O
in	O
Suriname	O
had	O
already	O
made	O
the	O
switch	O
to	O
ATSC	B-Device
.	O
</s>
<s>
South	O
Korea	O
completed	O
its	O
transition	O
to	O
ATSC	B-Device
on	O
December	O
31	O
,	O
2012	O
,	O
although	O
it	O
still	O
operates	O
some	O
analog	O
signals	O
along	O
its	O
northern	O
border	O
for	O
reception	O
in	O
North	O
Korea	O
.	O
</s>
<s>
territories	O
in	O
the	O
Pacific	O
,	O
including	O
American	O
Samoa	O
,	O
Guam	O
,	O
and	O
the	O
Northern	O
Mariana	O
Islands	O
have	O
adopted	O
ATSC	B-Device
,	O
as	O
with	O
the	O
mainland	O
.	O
</s>
<s>
The	O
following	O
organizations	O
hold	O
patents	O
for	O
the	O
development	O
of	O
ATSC	B-Device
technology	O
,	O
as	O
listed	O
in	O
the	O
patent	O
pool	O
administered	O
by	O
MPEG	O
LA	O
.	O
</s>
