CSO, CTB & XMOD characterisation of CATV line extenders with the aid of vector signal generators

The fact that cable TV networks are generally located in densely populated areas or extend over large geographical regions makes the presence of line extenders at regular intervals a necessity. Cascading large numbers of amplifiers however calls for excellent noise, SWR and intermodulation distortion specifications for the integrated amplifiers in order to avoid quality of service dropping below minimum acceptable levels. Composite second order, composite triple beat & cross modulation are commonly used figures to specify the performance of CATV equipment. In this application note we describe how to determine these figures with the aid of R&S SMU200A or AFQ100A and SMV vector signal generators.