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Volume 3 (Aug 01, 2003)
Commercialization of orthogonal frequency division multiplexing (OFDM) demodulation LSI chip for digital terrestrial broadcast mobile receivers (1/2)
What is digital terrestrial broadcasting?
Digital terrestrial broadcasting will begin in Japan's three major metropolitan areas of Tokyo, Osaka and Nagoya at the end of this year. According to the national plan, existing analog terrestrial broadcasting is set to be completely digitalized by July 24, 2011 (Figure 1).
Digital terrestrial broadcasting is expected to not only lead to the realization of multichannelization, extended-definition TV and high sound quality, but also make it possible to provide bidirectional (interactive) services, thus bringing to fruition new services and diverse applications that have never before been available.
Current world status
While there are three transmission routes for television broadcasting (terrestrial, cable and satellite), developed nations throughout the world are currently rushing to implement and diffuse the digitalization of terrestrial broadcasting. In fact, digital terrestrial broadcasting has already begun in Western countries such as the U.S., England and Germany, as well as in Asian countries including Singapore and Korea. In Japan, cable TV began to provide partial digital broadcasting starting in July 1998. And then in December 2000, NHK, five major commercial TV broadcast companies, WOWOW and others, began BS digital broadcasting through the use of broadcast satellites (BS), thereby making it possible to offer digital high-vision and data broadcasting.
What are the features of digital technology?
Typical features of digital technology include strong resistance to background noise, significant band compression capabilities for video and audio signals and ease of search, processing and editing functions for information. When existing analog broadcasting becomes digitalized, broadcasting will be capable of the following functions.
1) Provision of high-quality broadcasting
High-quality broadcasting will be realized because not only is digital broadcasting technology highly resistant to background noise, it is also capable of reception more favorable than that of analog broadcasting technology even in the case of weak signals.
2) Transmission of high-definition and multiple TV programs using a fixed transmission bandwidth
By effectively compressing digital image information, large amounts of information can be transmitted using a fixed transmission bandwidth. For this reason, both the transmission of high-definition TV programs via terrestrial broadcasting and multichannelization (HDTV/1 channel or SDTV/3 channels at 6 MHz bandwidth) will be possible due to the fine detail of images.
3) Integration of services and flexible organization
Because the transmission capacity of digital signals such as images, sounds and data can be flexibly distributed, information can be integrated, organized and broadcast in a variety of ways.
New trends expected to be generated through digital terrestrial broadcastingNEC Electronics - The first company to commercialize an OFDM demodulation LSI chip
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