This edition includes the following significant technical changes with respect to the previous edition: Revised title and scope Clause 3, several new terms and definitions Subclause 4.1, Methods of measurement for digitally modulated signals Subclause ?4.6.2, RF signal-to-noise ratio (SD,RF/N) for digitally modulated signals Subclause ?4.8.2, Procedure for the measurement of group delay variation on DVB channel converters Subclause ?4.9, Phase noise of an RF carrier Subclause ?4.15, Decoding margin (Teletext). ?Annex D, Special national conditions. ?Annex E, Correction factors for noise. ?Annex F, Digital signal level and bandwidth. ?Annex G, Minimum frequency distance of converted satellite signals in the IF range. ?Annex H, Measurement errors which occur due to mismatched equipment. .?Annex I, Correction factor for spectrum analyser