Additional signalling for Digital Video Broadcasting

摘要

Methods and apparatus are described for transmitting data comprising one or more frames (100 Figure 1), such as Digital Video Broadcast data. These frames comprise a preamble section (110 Figure 1) and a data section (120 Figure 1), the preamble section having a synchronization function and carrying at least signalling information. Transmitting and receiving examples are described that operate on a superimposed sequence 770 (also 960 Figure 9) comprising a second modulated sequence 765 (also 955 Figure 9) that is superimposed upon a first modulated sequence 735 (also 935 Figure 9). The second modulated sequence is based on a second modulation scheme capable of non-coherent detection that provides continuous variation of the second modulated sequence across the length of the first modulated sequence. Examples using hierarchical differential phase shift keying and repeated sequences (945 Figure 9) of chirps and tones are further described. Described examples have an advantage of increasing the capacity of a preamble section to accommodate future signalling modes, whilst maintaining the synchronization function of the preamble section as well as backward compatibility. The term superimposing may involve multiplication of the two sequences, ANDâ ing them or performing bit-addition.