DVB-S (abbreviation for Digital Video Broadcasting - Satellite); Digital Satellite Television and the successor standard DVB-S2 (S2=satellite 2nd generation) are designations for the transmission of DVB signals via broadcast satellite. DVB broadcasting via satellite (e.g. Astra, Eutelsat) is the most widely used DVB variant. Thanks to the high data transmission rate, most television and radio programs as well as additional services are successful and effectively transmitted applying this method. The Astra satellites alone transmit more than 1,500 radio and television programs, of which almost 300 are television programs and tele media services, and some 170 radio stations are unencrypted. In contrast to DVB-C (C stands for 'cable'), DVB-T (T means terrestrial) which are still in quite common use as a traditional service for the transmission of radio and television programs, DVB-S does not require any additional infrastructure (cable networks, terrestrial transmitter chains) and thus also offers radio and TC reception in remote areas. There are parabolic antennas which, by automatically tracking the antenna, enable reception in airplanes, on ships or even in buses while driving. Therefore, the term 'general television' applies more to DVB-S than to DVB-T. DVB-S even usually serves as a data provider for the cable networks or DVB-T.
Unlike DVB-C, DVB-S does not incur running costs (apart from pay-tv), since satellite operation is paid for by the broadcasters. However, since older TV sets cannot receive the DVB-S signal directly, it is usually necessary to use a digital receiver. An important advantage of DVB-S is that, in contrast to analogue transmission, several channels can be broadcast on one transponder (MCPC). This represents a cost advantage for program providers, as the rental of a satellite transponder is very cost-intensive. The number of program transmitted simultaneously via a transponder depends on the data transmission rate assigned to the respective programs. The average number of programs for SDTV is approx. eight full TV channels with average resolution, HDTV at approx. four programs.
DVB-S contains optimizations for the satellite-specific properties (missing reflections, low carrier-to-noise ratio (CNR), low crest factor signal) in the transmission of digital data. QPSK (Quadrature Phase Shift Keying) modulation is used. Very high symbol rates greater than 10,000 kSym/s are used for MCPC signals ("Multiple Channel per Carrier", several channels per carrier frequency) and low symbol rates less than 10,000 kSym/s for SCPC signals ("Single Channel per Carrier", one channel per carrier frequency). Since, in contrast to digital cable signals (i.e. DVB-C), an external error protection (FEC) is necessary due to the transmission mode via satellite, high error correction components of typically 1/6 to 1/3 of the gross data rate result in the data stream. With DVB-S2, despite the better correction procedure, the required error correction rate is usually just as high or even higher, since 8 PSK is usually used instead of 4 PSK (QPSK).
The Serial Digital Interface (SDI) is a serial, digital interface, primarily for the transmission of uncompressed and unencrypted video data via coaxial cable or fiber optic. It is mainly used in the field of professional television studios and television broadcasters. The SDI interface is specified by the Society of Motion Picture and Television Engineers (SMPTE) and represents a further development of analog video standards such as PAL and NTSC method. The HD-SDI extension according to the SMPTE 292M standard is currently the predominant connection for the transmission of uncompressed picture signals for HD, digital intermediate and digital cinema in the studio and production environment. Picture, sound and metadata can be transmitted over all HD-SDI connections. HD-SDI, like SDI in general, is mainly found in professional video devices, for consumers interfaces of lower performance have established themselves. HD-SDI devices are usually only found in studios, rental houses and cinemas. A relatively new field of application is video surveillance systems, where this standard can be used to transmit images from special HD cameras over existing coaxial cable installations. HD-SDI thus enables high-resolution images in this sector without a complete conversion to IP video.
In order to combine both techniques, it is necessary to select an appropriate integrated receiver/decoder, which will ensure the use of all the advanced possibilities of digital technology and will provide the user with numerous practical functionalities and their configurations, depending on very specific needs. Below you’ll find four Thor Broadcast’s proposals.
Professional DVBS to SDI conversion methods that have being developing by Thor Broadcast provide for professional and high advanced multi tech solutions represented by wide range of devices available.
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