NXP Semiconductors MC9S12G - Page 1216

Electrical Characteristics
MC9S12G Family Reference Manual Rev.1.27
1218 NXP Semiconductors
Figure A-4. Jitter Definitions
The relative deviation of t
nom
is at its maximum for one clock period, and decreases towards zero for larger
number of clock periods (N).
Defining the jitter as:
For N < 100, the following equation is a good fit for the maximum jitter:
Figure A-5. Maximum Bus Clock Jitter Approximation
NOTE
On timers and serial modules a prescaler will eliminate the effect of the jitter
to a large extent.
23 N-1N1
0
t
nom
t
max1
t
min1
t
maxN
t
minN
JN max 1
t
max
N
Nt
nom

-----------------------
– 1
t
min
N
Nt
nom

-----------------------
–,



=
JN
j
1
N
--------
=
1 5 10 20 N
J(N)