
96-16 Displays and Recorders
there is a long string of 0s in the input data. In addition, reproducing circuits are usually not designed
fo
r
dc sig
nal
pr
ocessing
. In fr
equency
mo
dulation
(F
M)
co
de,
th
ere
is al
ways
a tr
ansition
at th
e
bi
t-cell
bo
undary
wh
ich
ac
ts
as a cl
ock
. e
re
is al
so
an ad
ditional
tr
ansition
at th
e
bi
t-cell
ce
nter
fo
r
ea
ch
1 an
d
no tr
ansition
fo
r
0s. It re
duces
th
e
dc co
mponent
sig
nicantly
. e pr
imary
de
ciency
is th
e
re
duction
of l
inear
d
ensity
si
nce
t
here
a
re
t
wo
t
ransitions
f
or
e
ach
1 i
n
t
he
d
ata
.
e mo
st
po
pularly
us
ed
co
des
fo
r
ma
gnetic
re
cording
ar
e
th
e
ru
n
le
ngth–limited
(R
LL)
co
des
. e
y
have the general form of m/