ISDB in the context of "PAL"

Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. In the 2000s it was represented as the first significant evolution in television technology since color television in the 1950s. Modern digital television is transmitted in high-definition television (HDTV) with greater resolution than analog TV. It typically uses a widescreen aspect ratio (commonly 16:9) in contrast to the narrower format (4:3) of analog TV. It makes more economical use of scarce radio spectrum space; it can transmit up to seven channels in the same bandwidth as a single analog channel, and provides many new features that analog television cannot. A transition from analog to digital broadcasting began around 2000. Different digital television broadcasting standards have been adopted in different parts of the world; below are the more widely used standards:

• Digital Video Broadcasting (DVB) uses coded orthogonal frequency-division multiplexing (OFDM) modulation and supports hierarchical transmission. This standard has been adopted in Europe, Africa, Asia and Australia, for a total of approximately 60 countries.
• Advanced Television System Committee (ATSC) standard uses eight-level vestigial sideband (8VSB) for terrestrial broadcasting. This standard has been adopted by 9 countries: the United States, Canada, Mexico, South Korea, Bahamas, Jamaica, the Dominican Republic, Haiti and Suriname.
• Integrated Services Digital Broadcasting (ISDB) is a system designed to provide good reception to fixed receivers and also portable or mobile receivers utilizing OFDM and two-dimensional interleaving. It supports hierarchical transmission of up to three layers and uses MPEG-2 video and Advanced Audio Coding. This standard has been adopted in Japan and the Philippines. ISDB-T International is an adaptation of this standard using H.264/MPEG-4 AVC, which has been adopted in most of South America as well as Botswana and Angola. 1seg (1-segment) is a special form of ISDB. Each channel is further divided into 13 segments. Twelve are allocated for HDTV and the other for narrow-band receivers such as mobile televisions and cell phones.
• Digital Terrestrial Multimedia Broadcast (DTMB) adopts time-domain synchronous (TDS) OFDM technology with a pseudo-random signal frame to serve as the guard interval (GI) of the OFDM block and the training symbol. The DTMB standard has been adopted in China, including Hong Kong and Macau.
• Digital Multimedia Broadcasting (DMB) is a digital radio transmission technology developed and adopted in South Korea as part of the national information technology project for sending multimedia such as TV, radio and datacasting to mobile devices such as mobile phones, laptops and GPS navigation systems.

A television channel, or TV channel, is a terrestrial frequency or allocated number over which a television station or television network is distributed. For example, in North America, channel 2 refers to the terrestrial or cable band of 54 to 60 MHz, with carrier frequencies of 55.25 MHz for NTSC analog video (VSB) and 59.75 MHz for analog audio (FM), or 55.31 MHz for digital ATSC (8VSB). Channels may be shared by many different television stations or cable-distributed channels depending on the location and service provider.

Depending on the multinational bandplan for a given region, analog television channels are typically 6, 7, or 8 MHz in bandwidth, and therefore television channel frequencies vary as well. Channel numbering is also different. Digital terrestrial television channels are the same as their analog predecessors for legacy reasons, however through multiplexing, each physical radio frequency (RF) channel can carry several digital subchannels. On satellites, each transponder normally carries one channel, however multiple small, independent channels can be on one transponder, with some loss of bandwidth due to the need for guard bands between unrelated transmissions. ISDB, used in Japan and Brazil, has a similar segmented mode.

Television in Japan was introduced in 1939. However, experiments date back to the 1920s, with Kenjiro Takayanagi's pioneering experiments in electronic television. Television broadcasting was halted by World War II, after which regular television broadcasting began in 1950. After Japan developed the first HDTV systems in the 1960s, MUSE/Hi-Vision was introduced in the 1970s.

A modified version of the NTSC system for analog signals, called NTSC-J, was used for analog broadcast between 1950 and the early 2010s. The analog broadcast in Japan was replaced with a digital broadcasts using the ISDB standard. ISDB supersedes both the NTSC-J analog television system and the previously used MUSE Hi-vision analog HDTV system in Japan. Digital Terrestrial Television Broadcasting (DTTB) services using ISDB-T (ISDB-T International) started in Japan in December 2003, and since then, Japan adopted ISDB over other digital broadcasting standards.

Advanced Television Systems Committee (ATSC) standards are an international set of standards for broadcast and digital television transmission over terrestrial, cable and satellite networks. It is largely a replacement for the analog NTSC standard. Like NTSC, ATSC is used mostly in the United States, Mexico, Canada, South Korea, and Trinidad and Tobago. Several former NTSC users like Japan have not used ATSC during their digital television transition, because they adopted other systems like ISDB developed by Japan and DVB developed in Europe, for example.

The ATSC standards were developed in the early 1990s by the Grand Alliance, a consortium of electronics and telecommunications companies that assembled to develop a specification for what is now known as HDTV. The standard is now administered by the Advanced Television Systems Committee. It includes a number of patented elements, and licensing is required for devices that use these parts of the standard. Key among these is the 8VSB modulation system used for over-the-air broadcasts. ATSC 1.0 technology was primarily developed with patent contributions from LG Electronics, which held most of the patents for the ATSC standard.

1seg (ワンセグ, wansegu) is a mobile terrestrial digital audio/video and data broadcasting service in Japan, Argentina, Brazil, Chile, Uruguay, Paraguay, Peru and the Philippines. Service began experimentally during 2005 and commercially on April 1, 2006. It is designed as a component of ISDB-T, the terrestrial digital broadcast system used in those countries, as each channel is divided into 13 segments, with a further segment separating it from the next channel; an HDTV broadcast signal occupies 12 segments, leaving the remaining (13th) segment for mobile receivers, hence the name, "1seg" or "One Seg".

Its use in Brazil was established in late 2007 (starting in just a few cities), with a slight difference from the Japanese counterpart: it is broadcast under a 30 fps transmission setting (Japanese broadcasts are under the 15 fps transmission setting).