Chapter 4
Analog Input
©
National Instruments Corporation
4-35
Figure 4-21.
ai/SampleClock and ai/ConvertClock Properly Matched
It is also possible to use a single external signal to drive both
ai/SampleClock and ai/ConvertClock at the same time. In this mode, each
tick of the external clock will cause a conversion on the ADC. Figure 4-22
shows this timing relationship.
Figure 4-22.
Single External Signal Driving ai/SampleClock and ai/ConvertClock
Simultaneously
AI Convert Clock Timebase Signal
The AI Convert Clock Timebase (ai/ConvertClockTimebase) signal is
divided down to provide on of the possible sources for ai/ConvertClock.
Use one of the following signals as the source of
ai/ConvertClockTimebase:
•
ai/SampleClockTimebase
•
20 MHz Timebase
ai/ConvertClockTimebase is not available as an output on the I/O
connector.
• Properly M
a
tched
Sa
mple Clock
a
nd Convert Clock
a
i/
Sa
mpleClock
a
i/ConvertClock
Sa
mple #1
Sa
mple #2
Sa
mple #
3
Ch
a
nnel Me
asu
red
1 2
3
0
1 2
3
0
1 2
3
0
• One External Signal Driving Both Clocks
ai/SampleClock
ai/ConvertClock
Sample #1 Sample #2 Sample #3
1 2 3
0
1 2 3
0
1 …
0
Channel Measured