<s>
Harvard	B-Device
biphase	I-Device
is	O
a	O
magnetic	O
run	O
length	O
code	O
for	O
encoding	O
magnetic	O
tape	O
.	O
</s>
<s>
Each	O
bit	O
in	O
the	O
Harvard	B-Device
biphase	I-Device
format	O
undergoes	O
change	O
at	O
its	O
trailing	O
edge	O
and	O
this	O
transpires	O
either	O
from	O
high	O
to	O
zero	O
or	O
zero	O
to	O
high	O
independently	O
of	O
its	O
value	O
.	O
</s>
<s>
Harvard	B-Device
biphase	I-Device
has	O
previously	O
been	O
used	O
for	O
digital	O
flight	O
data	O
recorder	O
(	O
FDR	O
)	O
where	O
12-bit	O
words	O
per	O
second	O
are	O
recorded	O
onto	O
magnetic	O
tape	O
using	O
Harvard	B-Device
biphase	I-Device
code	O
.	O
</s>
<s>
For	O
Harvard	B-Device
biphase	I-Device
,	O
a	O
phase	O
transition	O
in	O
the	O
middle	O
of	O
the	O
bit	O
cell	O
indicates	O
that	O
the	O
bit	O
is	O
1	O
.	O
</s>
<s>
The	O
ARINC	O
573	O
serves	O
as	O
a	O
standard	O
for	O
FDRs	O
that	O
feature	O
continuous	O
data	O
stream	O
encoded	O
in	O
Harvard	B-Device
biphase	I-Device
.	O
</s>
