A survey of digital television broadcast transmission techniques

This paper is a survey of the transmission techniques used in digital television (TV) standards worldwide. With the increase in the demand for High-Definition (HD) TV, video-on-demand and mobile TV services, there was a real need for more bandwidth-efficient, flawless and crisp video quality, which motivated the migration from analogue to digital broadcasting. In this paper we present a brief history of the development of TV and then we survey the transmission technology used in different digital terrestrial, satellite, cable and mobile TV standards in different parts of the world. First, we present the Digital Video Broadcasting standards developed in Europe for terrestrial (DVB-T/T2), for satellite (DVB-S/S2), for cable (DVB-C) and for hand-held transmission (DVB-H). We then describe the Advanced Television System Committee standards developed in the USA both for terrestrial (ATSC) and for hand-held transmission (ATSC-M/H). We continue by describing the Integrated Services Digital Broadcasting standards developed in Japan for Terrestrial (ISDB-T) and Satellite (ISDB-S) transmission and then present the International System for Digital Television (ISDTV), which was developed in Brazil by adopteding the ISDB-T physical layer architecture. Following the ISDTV, we describe the Digital Terrestrial television Multimedia Broadcast (DTMB) standard developed in China. Finally, as a design example, we highlight the physical layer implementation of the DVB-T2 standar

Demodulator techniques in satellite communication systems for direct broadcast systems

This thesis is concerned with the FM demodulator techniques used in terrestrial TV receiver designs for Direct Broadcast Systems (DBS) from satellites. The various MAC/Packet schemes intended for DBS applications are described and the international standards that apply to them considered, with particular emphasis on the D2-MAC system. Noise in FM systems is discussed and a suitable threshold noise model is chosen for use in DBS TV demodulator systems. The characteristics of the various types of noise effects are considered in terms of their effect upon the TV picture. The threshold performance of a conventional FM demodulator for differing types of modulation is reviewed and it is shown how the threshold characteristic depends upon the nature of the modulation. The literature review carried out represents a significant component of the thesis and combines material from patent literature with more conventional source materials from professional journals, conferences, textbooks, etc. Some ten existing demodulator concepts that exhibit threshold extension characteristics are examined, and where relevant their potential performance in D2-MAC format systems is assessed. The demodulator characteristics that limit their performance in TV systems are identified. It is concluded that designing a threshold extension demodulator, with reliable operation, for all picture contents and for a wide range of input carrier-to-noise ratios, is a formidable task using existing design techniques. On the basis of this examination an adaptive threshold extension demodulator concept is proposed, that utilises information contained within the signal structure to achieve an improved performance over a wide range of input carrier-to-noise ratios and picture content. It is shown how the relevant signal structures may be derived from conventional (PAL, SECAM and NTSC), MAC format and all-digital television systems. Illustrations are given that show how the adaptive demodulator concept can be applied to certain existing threshold extension demodulators, enhancing their performance for television picture reception. Future trends in all-digital DBS TV systems intended ultimately for DBS applications are briefly discussed together with their demodlilation requirements

A novel modulation strategy for integrating digital sub-channels within a PAL/PAL plus signal

This paper presents an original methodology which facilitates the modulation of digital signals within the active video portion of a conventional analogue PAL/PALplus television signal. The resultant crosstalk distortion errors which ensue are analysed and a model postulated that enables optimization of a number of important system parameters. It is also shown that applying this model enables a balancing of subjective quality with data-rat