National Instruments DAQ X Series User Manual page 211

Chapter 8 PFI
Filter Setting Filter Clock
None
90 ns 100 MHz
(short)
5.12 μs
100 MHz
(medium)
2.56 ms 100 kHz
(high)
Custom User
configurable
The filter setting for each input can be configured independently. On power
up, the filters are disabled. Figure 8-3 shows an example of a low to high
transition on an input that has a custom filter set to N = 5.
RTSI, PFI, or
PXI_STAR Terminal
Filter Clock
Filtered Input
Enabling filters introduces jitter on the input signal. The maximum jitter is
one period of the timebase.
When a RTSI input is routed directly to PFI, the X Series device does not
use the filtered version of the input signal.
X Series User Manual
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
Table 8-1. Filters
N (Filter Clocks
Needed to
Pass Signal)
— —
9
512
256
N
1 1 2 3 4 1
Figure 8-3. Filter Example
8-6
Pulse Width Pulse Width
Guaranteed to Guaranteed to
Pass Filter Not Pass Filter
—
90 ns
5.12 μs
2.56 ms
N/timebase (N – 1)/timebase
Filtered input goes
high when terminal
2 3 4 5
is sampled high on
five consecutive filter
clocks.
—
80 ns
5.11 μs
2.55 ms
ni.com