Chapter 8
PFI
X Series User Manual
8-6
ni.com
The filter setting for each inp
u
t can be config
u
red independently. On power
u
p, the filters are disabled. Fig
u
re 8-3 shows an example of a low to high
transition on an inp
u
t that has a c
u
stom filter set to N = 5.
Figure 8-3.
Filter Example
Enabling filters introd
u
ces jitter on the inp
u
t signal. The maxim
u
m jitter is
one period of the timebase.
When a RTSI inp
u
t is ro
u
ted directly to PFI, the X Series device does not
u
se the filtered version of the inp
u
t signal.
Table 8-1.
Filters
Filter Setting
Filter Clock
N (Filter Clocks
Needed to
Pass Signal)
Pulse Width
Guaranteed to
Pass Filter
Pulse Width
Guaranteed to
Not Pass Filter
None
—
—
—
—
90 ns
(short)
100 MHz
9
90 ns
80 ns
5.12
μ
s
(medi
u
m)
100 MHz
512
5.12
μ
s
5.11
μ
s
2.56 ms
(high)
100 kHz
256
2.56 ms
2.55 ms
C
u
stom
User
config
u
rable
N
N/timebase
(N – 1)/timebase
1 2
3
1 4
1
2
3
4 5
RT
S
I, PFI, or
PXI_
S
TAR Termin
a
l
Filtered inp
u
t goe
s
high when termin
a
l
i
s
sa
mpled high on
five con
s
ec
u
tive filter
clock
s
.
Filter Clock
Filtered Inp
u
t
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