<s>
It	O
is	O
designed	O
as	O
a	O
component	O
of	O
ISDB-T	O
,	O
the	O
terrestrial	O
digital	O
broadcast	O
system	O
used	O
in	O
those	O
countries	O
,	O
as	O
each	O
channel	O
is	O
divided	O
into	O
13	O
segments	O
,	O
with	O
a	O
further	O
segment	O
separating	O
it	O
from	O
the	O
next	O
channel	O
;	O
an	O
HDTV	B-Device
broadcast	O
signal	O
occupies	O
12	O
segments	O
,	O
leaving	O
the	O
remaining	O
(	O
13th	O
)	O
segment	O
for	O
mobile	O
receivers	O
,	O
hence	O
the	O
name	O
,	O
"	O
1seg	B-Device
"	O
or	O
"	O
One	B-Device
Seg	I-Device
"	O
.	O
</s>
<s>
The	O
ISDB-T	O
system	O
uses	O
the	O
UHF	O
band	O
at	O
frequencies	O
between	O
470	O
and	O
770MHz	O
(	O
806MHz	O
in	O
Brazil	O
)	O
,	O
giving	O
a	O
total	O
bandwidth	O
300MHz	O
.	O
</s>
<s>
1	B-Device
seg	I-Device
uses	O
a	O
single	O
of	O
these	O
segments	O
to	O
carry	O
the	O
1seg	B-Device
transport	O
stream	O
.	O
</s>
<s>
1seg	B-Device
,	O
like	O
ISDB-T	O
uses	O
QPSK	O
for	O
modulation	B-Application
,	O
with	O
2/3	O
forward	B-Error_Name
error	I-Error_Name
correction	I-Error_Name
and	O
1/4	O
guard	O
ratio	O
.	O
</s>
<s>
The	O
television	O
system	O
uses	O
an	O
H.264/MPEG	B-Application
-4	I-Application
AVC	I-Application
video	O
stream	O
and	O
an	O
HE-AAC	O
audio	O
stream	O
multiplexed	O
into	O
an	O
MPEG	O
transport	O
stream	O
.	O
</s>
<s>
Additional	O
data	O
(	O
EPG	B-Device
,	O
interactive	O
services	O
,	O
etc	O
.	O
)	O
</s>
<s>
is	O
transmitted	O
using	O
BML	B-Device
and	O
occupies	O
the	O
remaining	O
10	O
to	O
100	O
kbit/s	O
of	O
bandwidth	O
.	O
</s>
<s>
Conditional	O
access	O
and	O
copy	O
control	O
are	O
implemented	O
in	O
1seg	B-Device
broadcasting	O
by	O
the	O
use	O
of	O
Broadcast	O
Flag-like	O
structure	O
contained	O
in	O
the	O
"	O
Copy	O
Control	O
Descriptor	O
"	O
within	O
the	O
broadcast	O
.	O
</s>
<s>
Broadcast	B-Device
Markup	I-Device
Language	I-Device
(	O
BML	B-Device
)	O
,	O
is	O
a	O
data-transmission	O
service	O
allowing	O
text	O
to	O
be	O
displayed	O
on	O
a	O
1seg	B-Device
TV	O
screen	O
.	O
</s>
<s>
EPG	B-Device
(	O
program	B-Device
guides	I-Device
)	O
is	O
not	O
included	O
,	O
but	O
transmitted	O
in	O
separate	O
stream	O
(	O
EIT	O
)	O
.	O
</s>
<s>
Most	O
1seg	B-Device
receivers	O
manufactured	O
after	O
September	O
2008	O
are	O
compatible	O
with	O
this	O
technology	O
.	O
</s>
<s>
Multiple-program	O
arrangement	O
in	O
1seg	B-Device
is	O
named	O
as	O
.	O
</s>
<s>
Until	O
the	O
end	O
of	O
March	O
2008	O
,	O
Japanese	O
regulation	O
required	O
that	O
the	O
programs	O
on	O
1seg	B-Device
were	O
fundamentally	O
the	O
same	O
as	O
those	O
broadcast	O
on	O
the	O
equivalent	O
HDTV	B-Device
channel	O
.	O
</s>
<s>
On	O
April	O
1	O
the	O
regulation	O
was	O
revised	O
,	O
and	O
experimental	O
programs	O
by	O
1seg	B-Device
or	O
third	O
parties	O
have	O
begun	O
airing	O
on	O
several	O
stations	O
.	O
</s>
<s>
3.054	O
million	O
phones	O
,	O
63.5	O
%	O
of	O
the	O
total	O
,	O
can	O
receive	O
1seg	B-Device
broadcasts	O
.	O
</s>
<s>
In	O
the	O
fiscal	O
year	O
of	O
2007	O
,	O
on	O
average	O
45%	O
of	O
mobile	O
phones	O
had	O
1seg	B-Device
reception	O
capability	O
out	O
of	O
the	O
22.284	O
million	O
units	O
sold	O
.	O
</s>
<s>
The	O
first	O
mobile	O
phone	O
handsets	O
able	O
to	O
support	O
1seg	B-Device
were	O
sold	O
by	O
au	O
by	O
KDDI	O
to	O
consumers	O
in	O
autumn	O
2005	O
.	O
</s>
<s>
Today	O
,	O
almost	O
all	O
mobile	O
phones	O
sold	O
in	O
Japan	O
feature	O
a	O
1seg	B-Device
antenna	O
(	O
only	O
for	O
and	O
Android	B-Application
smartphones	O
sold	O
by	O
carriers	O
,	O
iOS	B-Application
users	O
must	O
purchase	O
a	O
third-party	O
1seg	B-Device
antenna	O
separately	O
)	O
.	O
</s>
