Chapter 9 Digital Routing and Clock Generation
NI 6124/6154 User Manual 9-2 ni.com
80 MHz Timebase
The 80 MHz Timebase can be used as the Source input to the 32-bit
general-purpose counter/timers.
The 80 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 normally generates many of the AI and AO timing
signals. The 20M Hz Timebase also can be used as the Source input to the
32-bit general-purpose counter/timers.
The 20 MHz Timebase is generated by dividing down the 80MHz
Timebase.
100 kHz Timebase
The 100 kHz Timebase can be used to generate many of the AI and AO
timing signals. The 100kHz Timebase also can be used as the Source input
to the 32-bit general-purpose counter/timers.
The 100 kHz Timebase is generated by dividing down the 20MHz
Timebase by 200.
External Reference Clock
The external reference clock can be used as a source for the internal
timebases (80 MHz Timebase, 20 MHz Timebase, and 100 kHz Timebase)
on an SS eries 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>
•PXI_CLK10
•PXI_STAR
The external reference clock is an input to a Phase-Lock Loop (PLL). The
PLL generates the internal timebases.