National Instruments DAQ X Series, Руководство пользователя

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Chapter 9 Digital Routing and Clock Generation
X Series User Manual 9-2 ni.com
100 MHz Timebase
The 100 MHz Timebase can be u sed as the timebase for all internal
s u bsystems.
The 100 MHz Timebase is generated from the following so u rces:
• Onboard oscillator
• External signal (by u sing the external reference clock)
20 MHz Timebase
The 20 MHz Timebase can be u sed to generate many of the AI and AO
timing signals.The 20 MHz Timebase also can be u sed as the So u rce inp u t
to the 32-bit general-p u rpose co u nter/timers.
The 20 MHz Timebase is generated by dividing down the 100 MHz
Timebase.
100 kHz Timebase
The 100 kHz Timebase can be u sed to generate many of the AI and AO
timing signals. The 100 kHz Timebase also can be u sed as the So u rce inp u t
to the 32-bit general-p u rpose co u nter/timers.
The 100 kHz Timebase is generated by dividing down the 20 MHz
Timebase by 200.
External Reference Clock
The external reference clock can be u sed as a so u rce for the internal
timebases (100 MHz Timebase, 20 MHz Timebase, and 100 kHz
Timebase) on an X Series device. By
u sing the external reference clock,
yo u can synchronize the internal timebases to an external clock.
The following signals can be ro u ted to drive the external reference clock:
• RTSI <0..7>
• PFI <0..15>
• PXIe_CLK100
• PXI_STAR
• PXIe-DSTAR<A,B>
The external reference clock is an inp u t to a Phase-Lock Loop (PLL). The
PLL generates the internal timebases.
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