Can I add a stub (or a test point) to the high-speed differential lines?

Description

Since the stub or the test point would degrade signal integrity, Altera does not recommended that you add a stub or a test point to the high-speed differential lines. If you follow the guidelines for high-speed design, you will not need to probe those lines. However, during prototyping, you can route one or two dedicated high-speedchannels to SMA connectors to check for signal integrity.