Datasheet

Appendix A Electrical Characteristics
MC9S12E128 Data Sheet, Rev. 1.07
Freescale Semiconductor 579
Figure A-3. 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:
This is very important to notice with respect to timers, serial modules where a pre-scaler will eliminate the
effect of the jitter to a large extent.
2 3 N-1 N1
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
⋅
---------------------
–,
⎝⎠
⎜⎟
⎛⎞
=
J
N()
j
1
N
--------
j
2
+=
1 5 10 20 N
J
(N)