<s>
In	O
telecommunication	O
,	O
a	O
Berger	B-Error_Name
code	I-Error_Name
is	O
a	O
unidirectional	B-Error_Name
error	I-Error_Name
detecting	O
code	O
,	O
named	O
after	O
its	O
inventor	O
,	O
J	O
.	O
M	O
.	O
Berger	O
.	O
</s>
<s>
Berger	B-Error_Name
codes	I-Error_Name
can	O
detect	O
all	O
unidirectional	B-Error_Name
errors	I-Error_Name
.	O
</s>
<s>
Unidirectional	B-Error_Name
errors	I-Error_Name
are	O
errors	O
that	O
only	O
flip	O
ones	O
into	O
zeroes	O
or	O
only	O
zeroes	O
into	O
ones	O
,	O
such	O
as	O
in	O
asymmetric	O
channels	O
.	O
</s>
<s>
The	O
check	B-Error_Name
bits	I-Error_Name
of	O
Berger	B-Error_Name
codes	I-Error_Name
are	O
computed	O
by	O
counting	O
all	O
the	O
zeroes	O
in	O
the	O
information	O
word	O
,	O
and	O
expressing	O
that	O
number	O
in	O
natural	O
binary	O
.	O
</s>
<s>
If	O
the	O
information	O
word	O
consists	O
of	O
bits	O
,	O
then	O
the	O
Berger	B-Error_Name
code	I-Error_Name
needs	O
"	O
check	B-Error_Name
bits	I-Error_Name
"	O
,	O
giving	O
a	O
Berger	B-Error_Name
code	I-Error_Name
of	O
length	O
k+n	O
.	O
</s>
<s>
(	O
In	O
other	O
words	O
,	O
the	O
check	B-Error_Name
bits	I-Error_Name
are	O
enough	O
to	O
check	O
up	O
to	O
information	O
bits	O
)	O
.	O
</s>
<s>
Berger	B-Error_Name
codes	I-Error_Name
can	O
detect	O
any	O
number	O
of	O
one-to-zero	O
bit-flip	O
errors	O
,	O
as	O
long	O
as	O
no	O
zero-to-one	O
errors	O
occurred	O
in	O
the	O
same	O
code	O
word	O
.	O
</s>
<s>
Similarly	O
,	O
Berger	B-Error_Name
codes	I-Error_Name
can	O
detect	O
any	O
number	O
of	O
zero-to-one	O
bit-flip	O
errors	O
,	O
as	O
long	O
as	O
no	O
one-to-zero	O
bit-flip	O
errors	O
occur	O
in	O
the	O
same	O
code	O
word	O
.	O
</s>
<s>
Berger	B-Error_Name
codes	I-Error_Name
cannot	O
correct	O
any	O
error	O
.	O
</s>
<s>
Like	O
all	O
unidirectional	B-Error_Name
error	I-Error_Name
detecting	O
codes	O
,	O
</s>
<s>
Berger	B-Error_Name
codes	I-Error_Name
can	O
also	O
be	O
used	O
in	O
delay-insensitive	B-General_Concept
circuits	O
.	O
</s>
<s>
As	O
stated	O
above	O
,	O
Berger	B-Error_Name
codes	I-Error_Name
detect	O
any	O
number	O
of	O
unidirectional	B-Error_Name
errors	I-Error_Name
.	O
</s>
<s>
For	O
a	O
given	O
code	O
word	O
,	O
if	O
the	O
only	O
errors	O
that	O
have	O
occurred	O
are	O
that	O
some	O
(	O
or	O
all	O
)	O
bits	O
with	O
value	O
1	O
have	O
changed	O
to	O
value	O
0	O
,	O
then	O
this	O
transformation	O
will	O
be	O
detected	O
by	O
the	O
Berger	B-Error_Name
code	I-Error_Name
implementation	O
.	O
</s>
<s>
Unidirectional	B-Error_Name
errors	I-Error_Name
are	O
common	O
in	O
certain	O
situations	O
.	O
</s>
<s>
For	O
instance	O
,	O
in	O
flash	B-Device
memory	I-Device
,	O
bits	O
can	O
more	O
easily	O
be	O
programmed	O
to	O
a	O
0	O
than	O
can	O
be	O
reset	O
to	O
a	O
1	O
.	O
</s>
