Consumer digital technology
Irrespective of whether a DTV signal issues from a terrestrial transmitter or a satellite, or arrives by cable, many of the functions of a digital receiver are common. As we have seen, the source coding used is always MPEG-II compression in Europe and MPEG-II video with AC-3 audio compression in the US. The differences in the decoders, in equipment designed for the various delivery formats, is the corollary of the different modulation technologies we studied in the previous chapter. Notably, whereas satellite modulation is QPSK, cable is n-QAM, and terrestrial is COFDM or 8-VSB.
Looking at Figure 11.1, let’s consider the jobs that a digital receiver must perform in order to display a digital ...