scope:

This part of IEC 60728 deals with the transparent return path of cable networks operated in the frequency range between 5 MHz and 65 MHz or parts thereof. Higher frequencies may be used in fibre based networks. An active return path carries typically only return signals. A passive return path can be used for both return and forward signals. This standard lays down the basic methods of measurement for signals typically used in the return path of cable networks in order to assess the performance of those signals and their performance limits. All requirements refer to the performance limits, which shall be obtained between the reference points (Figure 1) of the return path system. One reference point is the network termination close to the subscriber. It is the last point where all forward and return signals are present and carried on the same cable. If no network termination point exists, the reference point is the system outlet. The other reference point is the input of the return signal receiver (or transceiver). At this point, the transparent signal path ends and beyond this point, the signal is treated in a nontransparent way. The return signal receiver can be situated at the headend but can also be at the node of the coaxial cell or at any other point of the network.