NI 5610 Onboard Reference Clock

The NI 5610 onboard 10 MHz OCXO reference clock offers superior accuracy and phase noise specifications to the 10 MHz reference built into most PXI chassis. When the NI 5610 is installed in Slot 2 of a PXI chassis, this reference can be used to drive the 10 MHz PXI backplane clock and serve as the master reference for the PXI system. Refer to the Timing Configurations topic for information about configuring this option. The following figure illustrates the timing circuit block diagram.

The preceding figure shows the routing of the 10 MHz frequency references. Notice that when the NI 5610 is programmed to lock to an external reference, the LOs still lock to the onboard OCXO, which is locked to the external reference.

Note  The NI PXI-5610 OCXO cannot lock to all 10 MHz references. The reference must meet the specifications provided in the specifications document for your module so that the OCXO can lock to the reference.

Tip  NI recommends that you do not lock the OCXO to a reference that is lower quality. In this situation, use the NI 5610 as the master reference clock instead.

Refer to the specifications document that shipped with your NI RF signal generator for NI 5610 onboard OCXO frequency reference specifications.