<s>
On	B-Device
–	I-Device
off	I-Device
keying	I-Device
(	O
OOK	O
)	O
denotes	O
the	O
simplest	O
form	O
of	O
amplitude-shift	O
keying	O
(	O
ASK	O
)	O
modulation	B-Application
that	O
represents	O
digital	B-General_Concept
data	I-General_Concept
as	O
the	O
presence	O
or	O
absence	O
of	O
a	O
carrier	O
wave	O
.	O
</s>
<s>
It	O
is	O
analogous	O
to	O
unipolar	B-Protocol
encoding	I-Protocol
line	B-Protocol
code	I-Protocol
.	O
</s>
<s>
On	B-Device
–	I-Device
off	I-Device
keying	I-Device
is	O
most	O
commonly	O
used	O
to	O
transmit	O
Morse	O
code	O
over	O
radio	O
frequencies	O
(	O
referred	O
to	O
as	O
CW	O
(	O
continuous	O
wave	O
)	O
operation	O
)	O
,	O
although	O
in	O
principle	O
any	O
digital	O
encoding	B-Protocol
scheme	I-Protocol
may	O
be	O
used	O
.	O
</s>
<s>
OOK	O
has	O
been	O
used	O
in	O
the	O
ISM	B-Algorithm
bands	I-Algorithm
to	O
transfer	O
data	O
between	O
computers	O
,	O
for	O
example	O
.	O
</s>
<s>
OOK	O
is	O
more	O
spectrally	B-Protocol
efficient	I-Protocol
than	O
frequency-shift	O
keying	O
,	O
but	O
more	O
sensitive	O
to	O
noise	O
when	O
using	O
a	O
regenerative	O
receiver	O
or	O
a	O
poorly	O
implemented	O
superheterodyne	O
receiver	O
.	O
</s>
