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Chapter 9
Digital Routing and Clock Generation
100 MHz Timebase
The 100 MHz Timebase can be used as the timebase for all internal subsystems.
The 100 MHz Timebase is generated from the following sources:
•
Onboard oscillator
•
External signal (by using the external reference clock)
20 MHz Timebase
The 20 MHz Timebase can be used to generate many of the AI and AO timing signals.The
20 MHz Timebase can also be used as the Source input to the 32-bit general-purpose
counter/timers.
The 20 MHz Timebase is generated by dividing down the 100 MHz Timebase.
100 kHz Timebase
The 100 kHz Timebase can be used to generate many of the AI and AO timing signals. The
100 kHz Timebase can also be used as the Source input to the 32-bit general-purpose
counter/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 used as a source for the internal timebases
(100 MHz Timebase, 20 MHz Timebase, and 100 kHz Timebase) on an X Series device.
By using the external reference clock, you can synchronize the internal timebases to an external
clock.
The following signals can be routed to drive the external reference clock:
•
RTSI <0..7>
•
PFI <0..15>
•
PXIe_CLK100
•
PXI_STAR
•
PXIe_DSTAR<A,B>
Note
(NI PXIe-6386/6396 Devices)
PXIe-6386 and PXIe-6396 devices differ in
several ways from other SMIO devices. For more information about these devices
related to external reference clocks, go to
ni.com/info
and enter the Info Code
smio14ms
.
The external reference clock is an input to a Phase-Lock Loop (PLL). The PLL generates the
internal timebases.
Summary of Contents for DAQ X NI 634 Series
Page 1: ...PXIe 6349...
