IEC TR 60728-3-2

Abstract

Scope: This part of IEC 60728 is applicable to the measurement of 5th order non-linearity for active electronic equipment which carries only digitally modulated television signals, sound signals and signals for interactive services. This method of measurement is specifically applicable to MATV installations but could be applied to broadband and channel selective amplifiers used in all kinds of cable networks. NOTE 1 The methods of measurement of non-linearity (intermodulation products) applicable to active equipment, when loaded with analogue signals, considered that third order intermodulation products were the most important ones. The new era of television digital signals, transmitted according to DVB-S/S2, DVB-C/C2 and DVB-T/T2 modulation formats, has shown that the non-linear distortions (intermodulation products) in active equipment, when loaded with digital signals, are significant up to the 5th order. NOTE 2 With this method of measurement it is possible to obtain information on non-linear distortions (intermodulation products) up to the 5th order in active wideband equipment, using only 5 carriers, placed in an appropriate and suitable way in the equipment bandwidth. Moreover, with this method of measurement it is possible to obtain information on non-linear distortions (up to the 5th order) in narrowband equipment (channel amplifiers and channel frequency converters) carrying DVB-C/C2 and/or DVB-T/T2 signals.