National Instruments PCI-6251 User Manual page 240

Sample Clock
Sample Clock signals the start of a sample (which, in turn, is a set of converts). Sample Clock is
generated from external or internal sources. The main internal source is the terminal count (TC)
of the SI counter that runs on the Sample Clock Timebase signal. All the sources for Sample
Clock are at the _i level and are selected using a multiplexer. The output of this multiplexer is
called Selected Sample Clock.
Figure B-15. Sample Clock and the Analog Input Timing Engine
Selected Reference Trigger
Terminal
Terminal
Terminal
Terminal
Terminal
Selected Sample Clock
Sync Convert Clock Timebase
Sample Clock
Selected Start Trigger
Selected Pause Trigger
Sample Clock Timebase
Sync Sample Clock Timebase
Convert Clock Timebase
Sync Convert Clock Timebase
Selected Sample Clock
Figure B-16. Sample Clock Timing Diagram
_i
POUT
Reference Trigger
Start Trigger
Pause Trigger SI Start
SI
Counter
Block
SI_TC
SI2
Counter
Block
Start
t
27
t
28
t
M Series User Manual
SI2_TC
1
RST
t
29
30
t
31
© National Instruments | B-15
Terminal
Terminal
RTSI
Terminal
p_AI_Convert
Terminal