You are here: Home Page » HDTV » World TV standards

World TV standards

Oct 1, 2007 12:00 PM, BY ALDO CUGNINI

ATSC, ISDB-T, DVB-T and DMB-T/H stake their claims.

DTMB

The Chinese government has developed a proprietary system, now called DTMB, for Digital Terrestrial Multimedia Broadcasting. Incorporating MPEG2 systems with video coding provisionally similar to MPEG-4/AVC, the transmission scheme features a layered frame structure synchronized with real time, a function developed for power saving. Single-carrier and multicarrier operation are possible, and four-level through 64-level QAM are supported.

Switchoff

The analog broadcasting switchoff varies by implementing country. Berlin-Brandenburg became the first region in the world to switch off its terrestrial analog signals in August 2003. In December 2006, the Netherlands was the first country to do so. In the United States, the analog switchoff is slated for February 2009, and while there has been some noise about possible delays, the push to free spectrum for “first responders” and emergency uses — together with pending spectrum auctions and the Federally mandated converter box program — most assuredly freezes that date. The switchoff of Japanese analog broadcasting — mandated by the Radio Law — is scheduled for 2011.

Conclusion

The variation in world digital TV standards is, for the most part, one of transmission system, with scanning formats now of lesser consequence, especially with the profusion of digital signal processing. While the promise of a universal TV system may have to await future developments, the display and storage of video have come closer to a ubiquitous norm.

---

Aldo Cugnini is a consultant in the digital television industry.

Send questions and comments to: aldo.cugnini@penton.com

Table 1. Terrestrial digital standards

Region		Transmission	Transport	Video	Audio
Africa	South Africa	DVBT	MPEG2	MPEG2	MPEG2
Asia	China	DTMB	MPEG2	MPEG2 or AVS-China	MPEG2 or AVS-China
	India	DVBT	MPEG2	MPEG2	MPEG2
	Japan	ISDBT			MPEG2/AAC
	Russia	DVBT			MPEG2
	South Korea	ATSC			AC-3
Australia		DVBT	MPEG2	MPEG2	MPEG2, AC-3
Europe		DVBT	MPEG2	MPEG2	MPEG2
North America	Canada	ATSC	MPEG2	MPEG2	AC-3
	Mexico
	United States
South America	Argentina	ATSC	MPEG2	MPEG2	AC-3
	Brazil	ISDBT			MPEG2/AAC
	Honduras	ATSC			AC-3

Table 2. The different standards have varying constituent elements, allowing local customization.

System	ATSC	DVBT	ISDBT	DTMB
Proposing region	United States	Europe	Japan	China
Transmission	Single carrier	Multiple carrier (OFDM)		Single carrier (QAM)/Multiple carrier (OFDM)
Bandwidth	6MHz/7MHz/8MHz	6MHz/7MHz/8MHz		8MHz
Modulation	8-VSB	QPSK/16-QAM/64-QAM	DQPSK/QPSK/16QAM/64QAM	4QAM/16QAM/32QAM/64QAM
Error correction	Trellis code + RS	Convolution code + RS		BCH code + LDPC code
Characteristic	Distributed-transmission capability	SFN capability	SFN capability, segmented OFDM, time interleaving	Time interleaving, frequency interleaving

Want to use this article? Click here for options!

Share this article

blog comments powered by Disqus