TABLE OF CONTENTS Digital TV reception is normally provided by an integrated receiver decoder ( IRD) commonly known as a set-top box ( STB). The STB may be either a standard (SD) or high definition (HD) as well as satellite or terrestrial. Digital terrestrial television ( DTTV) may also be incorporated within the TV receiver in what is known as integrated digital television ( iDTV). In this chapter, we will look at the component parts of a SD and HD STBs for both the terrestrial and satellite transmission media.
The set-top-box, STB is a self-contained tuner/decoder device in that it tunes to the required channel, extracts and decodes the selected programme data, checks the access rights of the user and produces picture, sound and other services as instructed.
Digital signals are fed to the STB in the same way as for analogue TV broadcasting. Thus, in the case of satellite transmission, an outdoor dish and low noise block ( LNB) are necessary to receive the signals and convert them to a suitable intermediate frequency (IF). For terrestrial television, the input to the STB is obtained directly from a terrestrial aerial. And for cable too, the signal is obtained directly from the network. The output from the SD digital decoder is in the form of analogue video and audio signals, that is fed to an analogue TV receiver either directly via a SCART component video or s-video connections or...
