The NI-5771 clock source controls the sample rate and other timing functions on the device. The following table contains information about the possible NI-5771 clock sources.
Table 1. NI-5771 Clock Sources
|Internal Clock Locked to Internal Reference
||The internal reference is free-running.
|Internal Clock PLL On (IoModSyncClock)
||The internal reference locks to PXI_CLK10 through IoModSyncClock, which is provided only through the backplane of PXIe-796x devices.
|Internal Clock PLL On (REF IN)
||The internal reference locks to an external Reference Clock (10 MHz), which is provided through the REF IN front panel connector.
|External Clock (CLK IN) 
||850 MHz to 1.5 GHz
||An external Sample Clock can be provided through the CLK IN front panel connector.