NI PXI/PCI-5401
PLL Ref Connector
The PLL Ref connector is a phase-locked loop (PLL) input connector that can accept a Reference clock from an external source and frequency lock the NI PXI/PCI-5401 internal clock to the external clock. The Reference clock should not deviate more than ±100 ppm from its nominal frequency. This clock does not require the minimum amplitude levels of 1 Vpk-pk. You can lock Reference clock frequencies of 1 MHz and 5–20 MHz in 1 MHz steps.
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Note You can frequency lock the NI PCI-5401 to other NI devices over the RTSI bus using the 20 MHz RTSI clock signal. You can frequency lock the NI PXI-5401 to other NI devices using the 10 MHz backplane clock. |
If a external Reference clock is not available, the NI 5401 automatically tunes the internal clock to the highest accuracy possible.