DVB-C
DVB -C ( short for "Digital Video Broadcasting - Cable", . Therefore dt " digital video transmission via cable " ) is a variant of DVB, which is used for the transmission of digital radio and television signals via cable connection.
Background
As with the other transmission antenna and satellite television, and cable television to be digitized so as to be able to transmit significantly more programs with a significantly better image quality with compression - the cable network reaches as previously used for an analog transmitter capacity for 10-12 stations in SDTV or 5-6 in HDTV.
The digital broadcasting can be synchronized with the image signal, and interactive features such as MHP, EPG and digital teletext be provided. Also commercial services such as video - on-demand ( VOD) and pay-per - view (PPV ) are feasible. These are - as well as the already known from the analogue era linear Pay TV - in encrypted form and can be subscribed for a fee. The decryption is performed on the digital receiver by using a personalized smart card. This is a standardized interface, the common interface is addressed. Chance also proprietary solutions without CI interface and smart card can be used.
After a long time only set- top boxes DVB -C were available (often just by the cable operator driven ), since about the year 2010, most new TVs are equipped with appropriate tuner. In contrast to other receiving Because the transmission of HDTV while based on the same version of the broadcast standards; nevertheless, the resolution and the video codec H.264 must be supported by the device.
Technology
The range of programs via DVB -C can be via a satellite position similar high as in DVB -S, although the range of these in the Ku- band is larger by about a factor of 4. The reason is that the QPSK modulation used by DVB -S more bandwidth per channel needs than the 256- QAM modulation mostly used by DVB -C.
As this modulation is the so-called Quadrature Amplitude Modulation (QAM ) is used. The cable provider Germany usually transmits it in the variant 256- QAM, which allows the highest bandwidth. Even 64- QAM is partly there but used. The used profile planes for video transmission include MPEG -2 MP @ ML, MPEG -2 MP @ HL and MPEG -4 AVC/H.264 HP @ L4. The latter allow the transmission of HDTV.
DVB -C2
Under the name of DVB- C2, a successor standard for DVB -C has already been developed, which, however, so far - unlike DVB -S2 for satellite and DVB -T2 for antenna - still find no practical application. This is mainly because that the broadcasting of HDTV and DVB- C is already possible and common.
The specification of the DVB -C2 standard was (ETSI ) published in April 2010 by the European Telecommunications Standards Institute as EN 302 769. DVB- C2 is thereby have great similarity to DVB -T2 and therefore as DVB-T2 based on the COFDM modulation method. In addition, the LDPC error correction and forward error correction to be introduced., The spectral efficiency increases of 50 Mbit / s per 8 MHz ( 6 bits / s Hz) DVB- C and 256-QAM for more than 80 Mbit / s per 8 MHz (10 bits / s, Hz) for DVB -C2 4096 QAM. The maximum downstream speed is increased by these two measures in an up to 862 MHz developed network from the current 5 Gbit / s to 8 Gb / s
While there have been several field tests with DVB -C2, a control mode is only in connection with the broadcast of UHDTV and then probably to be expected in HEVC video codec. The range of devices that are compatible with DVB -C2, the beginning of 2014 was still minimal.
History
Germany
The digitization was carried on the cable network much slower than other reception paths. In addition to no extra free to air public service broadcasters and the broadcaster Sky (then premiere) long time there was only a manageable service for cable, usually in the form of paid foreign programming packages. Only since January 2006, to receive digital cable in many cable networks, the programs of RTL Group and ProSiebenSat.1 Media. Was preceded by a year-long dispute with the operator of the transmitters on fees and encryption.
In the following period, all private stations were many suppliers grundverschlüsselt so that a paid smart card was required for the reception. It was not until the beginning of 2013, this encryption has generally been abandoned as a result of a decision of the Cartel.
The digital programs now exceeds significantly the analog supply; However, currently vacant places in the analog service will still always stocked new. While non-local third programs are replaced by small private stations primarily. There is currently no date for the complete shutdown of analogue channels, so that more bandwidth for digital transmission is not yet available. The implementation of this shutdown obligation for the end of 2014 in Saxony is currently considered unsafe. That it is the medium term lead to a shutdown, however, is certain.
HDTV programs are only offered very limited in the cable compared to satellite television, and (with the exception of the first, ZDF and Arte partially ) encrypted almost exclusively.
Austria
Cable television, and digital cable TV DVB -C is in Austria, especially in the urban centers, widely used, even though owners and tenants to install in an apartment building, in principle, enjoy the right to a satellite antenna. The program of the pay -TV provider Sky is usually also included in the offer as the digital version of the ORF programs.
The largest broadband providers outside the United States UPC Tele Cable with 550,000 cable TV customers in Austria, began on 21 May 2008 so that since 2001 "free" to-air digital programs, which as DVB -C standard definition ( 720x576) transport Stream were present at each coaxial cable, one to encrypt the course of numerous digital system conversions - of course had also previously analog fees are paid, it is more or less the complete program bouquet plus 60 digital radio stations. So since it was no longer possible to watch TV digitally by means of a commercially available DVB- C card on the PC / Mac or using the built in many TV sets the DVB-C receivers. Since February 4, 2013 UPC Tele Cable offers all previously only analog broadcasting TV channels now also again unverschüsselt in digital quality, which is necessary for only a TV with built-in DVB - C receiver.
Switzerland
In Switzerland, the DVB -C is very different depending on cable operators. The offer of the largest cable operator UPC Cablecom with over 50% market share in the cable TV sector comprises in July 2009, around 120 TV channels in the basic digital package and approximately 120 channels allocated to different pay- TV packages. There are also various HDTV channels and a video -on- demand service, which, however (as of July 2009) not yet available in all networks and not used for all set-top boxes of the UPC Cablecom is available. Alternatively, provided the UPC Cablecom to September 2009, a near-video -on- demand service. This offer included 16 Cinema stations (13 for movies and 3 Adult movies).
The other cable operators (more than 200 mostly small vendors together around 50 % market share) often provide a composite ( Quick Line, Digital Cable Group) one of the UPC Cablecom very similar offer. Both the UPC Cablecom, as with most small networks is coded the entire digital TV offering. The UPC Cablecom continues to a method of Nagravision, Conax many small networks. The encryption of the basic transport services should be prohibited by law in accordance with a motion of Simonetta Sommaruga, but this did not succeed.
The largest digital pay-TV provider is the Swiss platform Tele Club. You currently offers in its cable TV offering 17 channels. On the edge of German Switzerland and in western Switzerland a digital package of the French provider Canal Plus and CineCinema ( CanalSat ) is available.
End of 2008, according to industry association took Swisscable than 500,000 cable households digital TV. The growth rate in 2008 was around 25%. Switzerland's cable industry faces strong competition to an IPTV offering the largest Swiss telecoms provider Swisscom. This institution offers Swisscom TV is technically available in around 80 % of households and therefore a potential alternative.