System Reference
CNT24-4(PCI)
60
Block Diagram
The following is a block diagram of the CNT24-4(PCI) interface
board.
CNT24-4(PCI)
P
C
I
B
u
s
In
te
rf
ac
e
Sampling clock 16-bit counter
for digital filter
24-bit read register
24-bit counter
24-bit comparator
24-bit compare register
One-shot pulse output
System
clock
20MHz
Photocoupler
resistance input
(4channels)
TTL level input
(4 channels)
One-shot pulse output
(4 channels)
(photocoupler open
collector output)
P
C
I
B
u
s
D
ig
it
al
f
il
te
r
S
el
ec
to
r
B
u
ff
er
Figure 5.1. Block Diagram