<s>
Reduced-carrier	B-Device
transmission	I-Device
is	O
an	O
amplitude	B-Device
modulation	I-Device
(	O
AM	O
)	O
transmission	O
in	O
which	O
the	O
carrier	O
signal	O
level	O
is	O
reduced	O
to	O
reduce	O
wasted	O
electrical	O
power	O
.	O
</s>
<s>
Suppressed-carrier	O
transmission	O
is	O
a	O
special	O
case	O
in	O
which	O
the	O
carrier	O
level	O
is	O
reduced	O
below	O
that	O
required	O
for	O
demodulation	B-Device
by	O
a	O
normal	O
receiver	O
.	O
</s>
<s>
Carrier	O
power	O
must	O
be	O
restored	O
by	O
the	O
receiving	O
station	O
to	O
permit	O
demodulation	B-Device
,	O
usually	O
by	O
means	O
of	O
a	O
beat	O
frequency	O
oscillator	O
(	O
BFO	O
)	O
.	O
</s>
<s>
Failure	O
of	O
the	O
BFO	O
to	O
match	O
the	O
original	O
carrier	O
frequency	O
when	O
receiving	O
such	O
a	O
signal	O
will	O
cause	O
a	O
heterodyne	B-Algorithm
.	O
</s>
<s>
Suppressed	B-Device
carriers	I-Device
are	O
often	O
used	O
for	O
single	B-Device
sideband	I-Device
(	O
SSB	O
)	O
transmissions	O
,	O
such	O
as	O
for	O
amateur	O
radio	O
on	O
shortwave	O
.	O
</s>
<s>
That	O
system	O
is	O
referred	O
to	O
in	O
full	O
as	O
SSB	O
suppressed	B-Device
carrier	I-Device
(	O
SSBSC	B-Device
)	O
or	O
(	O
SSB-SC	O
)	O
.	O
</s>
<s>
International	O
broadcasters	O
agreed	O
in	O
1985	O
to	O
also	O
use	O
SSBSC	B-Device
entirely	O
by	O
2015	O
,	O
though	O
IBOC	O
and	O
IBAC	B-Device
digital	O
radio	O
(	O
namely	O
Digital	O
Radio	O
Mondiale	O
)	O
seems	O
likely	O
to	O
make	O
this	O
irrelevant	O
.	O
</s>
<s>
FM	O
stereo	O
transmissions	O
use	O
a	O
double-sideband	B-Device
suppressed	I-Device
carrier	I-Device
(	O
DSBSC	B-Device
)	O
signal	O
from	O
a	O
stereo	O
generator	O
,	O
together	O
with	O
a	O
pilot	O
tone	O
of	O
exactly	O
half	O
the	O
original	O
carrier	O
frequency	O
.	O
</s>
