This Technical Specification is applicable to the method of non-linearity measurement for active cable network equipment which carry a digital channel load in the return path. The digital channel load is represented by standard DVB-C signals. The method of measurement of the maximum operating output level takes account of a full channel load in the return path frequency range although different applications of return path amplifiers with partial channel load or single channel load are also in practical use. The maximum operating output level for applications with reduced channel loads could be derived from the result with a full channel load by applying a given calculation formula. The method considers the specific signal form and behaviour of digitally modulated signals and can be applied in the return path frequency range (5 MHz to 65 MHz) as well as in the extended return path frequency range (5 MHz to 85 MHz) according to EN 60728-10.