Chapter 3
Signal Connections
©
National Instruments Corporation
3-11
Fig
u
re 3-4 shows the timing req
u
irements for the Ctr
n
So
u
rce signal.
Figure 3-4.
Timing Requirements for Ctr
n
Source Signal
Fig
u
re 3-4 shows the minim
u
m p
u
lse width and period that yo
u
m
u
st
u
se
for the Ctr
n
So
u
rce signal. This signal m
u
st satisfy both minim
u
m criteria.
If the high phase of the Ctr
n
So
u
rce signal is Tsrcpw ns, the low phase m
u
st
be Tsrcper – Tsrcpw.
Table 3-4.
Minimum Pulse Width and Period for Ctr
n
Source Internal Signals
Parameter
Minimum
Minimum with
RTSI Connector
Description
NI 6601
NI 6602
Tsrcpw (witho
u
t
prescaling)
5 ns
5 ns
5 ns
Ctr
n
So
u
rce minim
u
m p
u
lse
width (witho
u
t prescaling)
Tsrcpw (with
prescaling)
3.5 ns
3.5 ns
3.5 ns
Ctr
n
So
u
rce minim
u
m p
u
lse
width (with prescaling)
Tsrcper (witho
u
t
prescaling)
50 ns
12.5 ns
50 ns
Ctr
n
So
u
rce minim
u
m period
(witho
u
t prescaling)
Tsrcper (with
prescaling)
16.67 ns
8 ns
16.67 ns
Ctr
n
So
u
rce minim
u
m period
(with prescaling)
Ctr
n
Source
Tsrcpw
Tgatepw
Tsrcper
