DVB-C stands for Digital Video Broadcasting - Cable and it is the DVB European consortium standard for the broadcast transmission of digital television over cable. For the chemical compound see Divinylbenzene. Digital Video Broadcasting ( DVB) is a suite of internationally accepted Digital television (DTV is the sending and receiving of moving images and sound by discrete ( digital) signals in contrast to the analog signals used by Coaxial cable is a cable consisting of an inner conductor surrounded by a tubular insulating layer typically made from a flexible material with a high Dielectric constant, all This system transmits an MPEG-2 or MPEG-4 family digital audio/video stream, using a QAM modulation with channel coding. MPEG-2 is a standard for "the generic coding of moving pictures and associated audio information" MPEG-4 is a collection of methods defining compression of audio and visual (AV digital data In Computer science, a channel code is a broadly used term mostly referring to the Forward error correction code and Bit interleaving in communication and

DVB-C2

On February 18, 2008 it was announced that a new standard - DVB-C2 - would be developed during 2008. The new standard should be ready very early in 2009.

The DVB TM-C2 issued on February 18. For the chemical compound see Divinylbenzene. Digital Video Broadcasting ( DVB) is a suite of internationally accepted 2008 a "Call for Technologies" for DVB-C2. DVB-C2 CfT Proposals including simulation programs and information on patent rights can be submitted until June 16. 2008. The draft standard should be ready very early 2009.

A very core point is the expectation that DVB-C2 will be the last cable standard ever, i. e. there will never be a -C3 standard.

"The results of the DVB-C2 Study Mission already provided clear indications that technologies are available allowing the performance of the second generation DVB cable transmission system to get so close to the theoretical Shannon Limit that any further improvements in the future would most likely not be able to justify the introduction of a disruptive third generation of cable transmission system. In Information theory, the Shannon–Hartley theorem is an application of the Noisy channel coding theorem to the archetypal case of a continuous-time analog communications " (DVB-C2 CfT)

The new standard may be ready for use late 2009 or more likely sometime during 2010 depending on the individual cable companies.

Technical description of the DVB-C transmitter

Scheme of a DVB-C transmission system

With reference to the figure, a short description of the single processing blocks follows.

• Source coding and MPEG-2 multiplexing (MUX): video, audio, and data streams are multiplexed into an MPEG-2 Programme Stream (PS). For multiplexing in electronics and signal processing see Multiplexer. Program stream ( PS or MPEG-PS) is a container format for multiplexing Digital audio, Video and more One or more PSs are joined together into a MPEG-2 Transport Stream (TS). Transport stream ( TS, TP, MPEG-TS, or M2T) is a Communications protocol for audio, video, and data This is the basic digital stream which is being transmitted and received by home Set Top Boxes (STB). A set-top box (STB or set-top unit (STU is a device that connects to a Television and an external source of signal, turning the signal into Allowed bitrates for the transported MPEG-2 depend on a number of modulation parameters: it can range from about 6 to about 64 Mbit/s (see the bottom figure for a complete listing). In Telecommunications and Computing, bitrate (sometimes written bit rate, data rate or as a Variable R or f b In telecommunications Bit rate or Data transfer rate is the average number of Bits characters or blocks per unit time passing between equipment in a data transmission

• MUX adaptation and energy dispersal: the MPEG-2 TS is identified as a sequence of data packets, of fixed length (188 bytes). In Information technology, a packet is a formatted unit of Data carried by a Packet mode Computer network. With a technique called energy dispersal, the byte sequence is decorrelated. In Probability theory and Statistics, correlation, (often measured as a correlation coefficient) indicates the strength and direction of a linear

• External encoder: a first level of protection is applied to the transmitted data, using a nonbinary block code, a Reed-Solomon RS (204, 188) code, allowing the correction of up to a maximum of 8 wrong bytes for each 188-byte packet. In Computer science, a block code is a type of Channel coding. Reed-Solomon error correction is an Error-correcting code that works by Oversampling a Polynomial constructed from the data

• External interleaver: convolutional interleaving is used to rearrange the transmitted data sequence, such way it becomes more rugged to long sequences of errors. Interleaving in Computer science is a way to arrange Data in a non- Contiguous way in order to increase performance

• Byte/m-tuple conversion: data bytes are encoded into bit m-tuples (m = 4, 5, 6, 7, or 8).

• Differential coding: the two most significant bytes in each m-tuple are encoded in order to give some ruggedness to the signal.

• QAM Mapper: the bit sequence is mapped into a base-band digital sequence of complex symbols. There are 5 allowed modulation modes: 16-QAM, 32-QAM, 64-QAM, 128-QAM, 256-QAM. In Telecommunications, modulation is the process of varying a periodic Waveform, i

• Base-band shaping: the QAM signal is filtered with a raised-cosine shaped filter, in order to remove mutual signal interference at the receiving side.

• DAC and front-end: the digital signal is transformed into an analog signal, with a digital-to-analog converter (DAC), and then modulated to radio frequency by the RF front-end. In Electronics, a digital-to-analog converter ( DAC or D-to-A) is a device for converting a digital (usually binary code to an Analog signal Front-end and back-end are generalized terms that refer to the initial and the end stages of a process

Available bitrates for a DVB-C system, assuming a ratio of 1. 15 between bandwidth and symbol rate. In Digital communications, symbol rate, also known as baud or modulation rate is the number of symbol changes (signalling events made to the transmission medium per second All (decimal) values in Mbit/s.

Technical description of the receiver

The receiving STB adopts techniques which are dual to those ones used in the transmission.

• Front-end and ADC: the analog RF signal is converted to base-band and transformed into a digital signal, using an analog-to-digital converter (ADC). An analog-to-digital converter (abbreviated ADC, A/D or A to D) is an electronic integrated circuit which converts continuous signals to

• QAM Demodulation
• Equalization
• Differential decoding
• Outer deinterleaving
• Outer decoding
• MUX adaptation
• MPEG-2 demultiplexing and source decoding
• Programmable Transport Stream

References

• ETSI Standard: ETSI EN 300 429 V1. The European Telecommunications Standards Institute ( ETSI) is an independent non-for-profit Standardization organization of the Telecommunications 2. 1 (1998-04), Digital Video Broadcasting (DVB); Framing structure, channel coding and modulation for cable systems, download from ETSI.

See also

• Digital Video Broadcasting (DVB)
• DMB (Digital Multimedia Broadcasting)
• Digital television (DTV)
• Digital television in Europe
• ATSC Standards

External links

• Website of the DVB Project
• DVB-C2 Webpage