National Instruments USB-621 Series, Руководство пользователя

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Chapter 5 Analog Output
© National Instruments Corporation 5-9 NI USB-621x User Manual
Fig u re 5-6 shows the relationship of AO Sample Clock to AO Start Trigger.
Figure 5-6. AO Sample Clock and AO Start Trigger
AO Sample Clock Timebase Signal
The AO Sample Clock Timebase (ao/SampleClockTimebase) signal is
divided down to provide a so
u rce for AO Sample Clock.
Yo u can ro u te any of the following signals to be the AO Sample Clock
Timebase signal:
• 20 MHz Timebase
• 100 kHz Timebase
•
(USB-6211/6215 Devices)
PFI <0..3>
•
(USB-6212/6216 Devices)
PFI <0..15>
•
(USB-6218 Devices)
PFI <0..3>, PFI <8..11>
AO Sample Clock Timebase is not available as an o u tp u t on the
I/O connector.
Yo u might u se AO Sample Clock Timebase if yo u want to u se an external
sample clock signal, b u t need to divide the signal down. If yo u want to u se
an external sample clock signal, b u t do not need to divide the signal, then
yo u sho u ld u se AO Sample Clock rather than AO Sample Clock Timebase.
AO Sa mple Clock Time bas e
AO S t a rt Trigger
AO Sa mple Clock
Del a y
From
S t a rt
Trigger