For some applications, the other synchronization methods might not be sufficient. In such cases, you might be able to synchronize by using a clock from one device as a different clock on another device. For example, to synchronize devices that use a Reference Clock with devices that use a Master Timebase, such as to synchronize X Series devices with E Series devices, you can perform Reference Clock synchronization, but instead of locking the X Series reference clock to a PXI backplane clock, lock it to the Master Timebase of the E Series device.
Mixing clocks in this manner is often much more complicated than using the same clocks. You might have to manually configure several other timing parameters, such as delays, active edges, or clock divisors. Use mixed-clock synchronization only as a last resort if the other synchronization methods are not an option.