Teledyne LeCroy QPHY-USB - Manual (Page 39)

QPHY-USB Software Option
QPHY-USB Operator’s Manual Rev F
39
Figure 40. Hub upstream repeater delay
The measured time delay between input and output sync fields should be less than 36 bits plus 4 ns (< 79 ns).
The 4 ns are added to account for the delay through the fixture.