scope:

This ETS defines the characteristics of the NICAM 728 1) system which allows for the transmission of twochannel digital sound and/or data services with terrestrial television systems B, G, H, I and L 2) defined in ITU-R Recommendation BT 470 [1].

a) It is sufficiently rugged to ensure that reception of the vision fails before reception of the digital sound in difficult reception conditions.

b) It fulfils the criteria for compatibility with existing services and receivers in over-air transmission and is adequately compatible in distribution on cable systems.

c) It provides two high-quality digital sound channels and a small amount of additional data capacity. The two sound channels may be used to transmit two independent monophonic signals, which could be received simultaneously, or a single stereophonic signal. Alternatively, one or both sound channels may be used for the transmission of data.

d) The sound coding is identical with that of one option available in the Multiplexed Analogue Component (MAC)/packet family of systems defined in EBU Technical document 3258-E [2].

e) The baseband coding and digital frame format are identical for all of the television systems considered; the differences in modulation parameters shown in subclause 5.2 are the minimum required to accommodate the existing differences between these television systems.

This ETS allows some scope for the addition of further features in a compatible fashion in the future.