Editor :
DM.Son
Document name
Project code
Version:
1.0
May. 19. 2016
ECO / DF No.
Identification No. : Document No.
File:
Page 4 / 6
.
P
ropri
e
ta
ry
dat
a,
c
o
m
p
any
c
onf
ident
ia
l.
A
ll
r
ight
s
res
e
rv
e
d
.
C
onf
ié
à
t
itr
e
de
s
e
c
ret
d'
e
n
tr
epr
is
e.
T
o
us
dr
oi
ts
rés
e
rv
és
.
C
o
m
u
ni
c
a
do
c
o
m
o
segr
edo
em
pr
es
a
ri
a
l.
R
e
se
rv
ados
t
o
dos
os
di
re
itos
.
C
onf
idado
co
m
o
s
e
cr
et
o
in
dus
tr
ia
l.
N
o
s
res
e
rv
am
os
t
odos
l
o
s derec
ho
s.
.
W
e
iterga
be s
o
w
ie V
er
vi
e
lfäl
tigung di
es
er U
n
te
rl
ag
e,
V
e
r-
w
e
rt
ung
und
M
itt
ei
lu
ng
ih
re
s
Inhal
ts
ni
ch
t ges
ta
ttet
, s
o
w
e
it
ni
ch
t
au
sd
rü
ck
lic
h
z
u
ges
tand
en.
Z
u
w
ider
handl
un
gen
v
e
r-
pf
lic
h
ten
zu
S
chadeners
a
tz
.
A
lle
R
e
ch
te
v
o
rbehal
te
n
,
in
sb
e
-
sondere
fü
r den F
a
ll der
P
a
te
nt
ert
e
ilung oder GM
-E
in
tr
agung
Technical aspects of 125 kHz – magnetic field:
virtually no reflections,
cubical decrease of field strength
allows good range control,
released frequency band (ISM),
high
penetration,
low quiescent current demand due to 125 kHz input stage (SMART KEY FOB),
less sensitive for detuning compared to higher frequency.
For the down-link from the SMART KEY FOB to the vehicle, the standard radio frequency
(RF) is used (similar to the classic remote control functions) with FSK modulation.
1.3
System Overview / Block Diagram
Figure 1: Principle of Communication
ECU sends LF challenge via exterior antenna
ID tag sends identification code to RF receiver
Doors are unlocked automatically
User pulls open the door
L
F
