Hello,
There is no way to directly inject noise into the USB transfer lines unless you opened up the board and wired something to the USB system.
Other than that, USB has a standard hardware interface. If you have motors or other devices that produce strong magnetic fields, they might induce current that could corrupt USB data transfers. Barring that and other environmental noise, you can just depend on the USB standards.
If this isn't what you are asking about, please write back with exactly what you are doing that can inject noise into the USB data transfer.
Thank you,
John N
Applications Engineer
National Instruments