I think what swept means is that a sample of that cable is tested by sending a signal from say 5 Mhz to 3,000 Mhz (3 Ghz) and seeing what the cable's response is. This basically determines if the cable stays at a 75 Ohm impedance over the frequency range and means that the loss versus frequency is gradual as it should be. The best specification would also mention what the SRL (Structural Return loss) is. This is a measure of impedance (Ohmage) or SWR. I think the best hardline cables for cable tv have an SRL of 30 db but RG type cables are more typicaly spec'd around 26 db SRL. I believe this also means if a cable has a signal on it, the imperfections in the cable will cause an echo signal to be set up that is 30 or 26 db weaker than the signal going in the forward direction. For analog video signals this shows up as a weak ghost to the right of the wanted signal- the more offset the ghost is the further away the mismatch is. For referance a direct short or a cable that is open (not terminated in a 75 Ohm load) has an SRL of 0 db meaning that the reflected echo is the same strength as the forward signal hitting the open or short.