RFSA PLL Could Not Phase Lock to External Reference Clock

Updated Jun 12, 2023

Reported In


  • PXI-5661

Issue Details

When trying to open the RFSA Soft Front Panel to use my vector signal analyzer, I receive an error:

"-223552 PLL could not phase lock to external reference clock; ensure that it is within jitter and phase specifications"

Why do I see this error and how can I correct it?



This error is commonly a result of incorrect cabling of the VSA. In the case of the PXI-5661, incorrectly connecting the 10 MHz PXI clock signal as noted in the Getting Started Guide  can cause this error. 

Ensure that all necessary connections are made with working cables on your modules to proceed.