<s>
An	O
acoustic	B-Device
tablet	I-Device
,	O
also	O
known	O
as	O
a	O
spark	O
tablet	O
,	O
is	O
a	O
form	O
of	O
graphics	B-Device
tablet	I-Device
that	O
uses	O
sound	O
to	O
locate	O
the	O
position	O
of	O
the	O
stylus	B-Device
within	O
the	O
drawing	O
area	O
.	O
</s>
<s>
The	O
general	O
functionality	O
of	O
acoustic	B-Device
tablets	I-Device
is	O
based	O
on	O
a	O
sound-emitting	O
stylus	B-Device
and	O
microphones	B-Application
that	O
are	O
used	O
to	O
record	O
the	O
sound	O
.	O
</s>
<s>
The	O
current	O
position	O
of	O
the	O
stylus	B-Device
can	O
be	O
calculated	O
according	O
to	O
the	O
difference	O
in	O
the	O
timing	O
of	O
the	O
recorded	O
sound	O
.	O
</s>
<s>
The	O
sound	O
can	O
,	O
for	O
example	O
,	O
be	O
a	O
small	O
electrical	O
discharge	O
that	O
is	O
emitted	O
when	O
the	O
stylus	B-Device
is	O
placed	O
near	O
the	O
surface	O
of	O
the	O
tablet	O
.	O
</s>
<s>
Acoustic	B-Device
tablets	I-Device
have	O
a	O
long	O
technological	O
history	O
,	O
as	O
seen	O
from	O
this	O
1971	O
patent	O
by	O
Science	O
Accessories	O
Corporation	O
.	O
</s>
<s>
Acoustic	B-Device
tablets	I-Device
are	O
a	O
convenient	O
way	O
to	O
make	O
a	O
digitizing	B-Device
tablet	I-Device
for	O
a	O
very	O
large	O
surface	O
area	O
,	O
as	O
in	O
the	O
products	O
.	O
</s>
