DVB-T is a technical standard developed by the DVB Project that specifies the framing structure, channel coding and modulation for digital terrestrial television (DTT) Broadcasting .
DVB-T, in common with almost all modern terrestrial transmission systems, uses OFDM (orthogonal frequency division multiplex) modulation. This type of modulation, which uses a large number of sub-carriers, delivers a robust signal that has the ability to deal with very severe channel conditions.
Overview
Using different combinations of the above parameters a DVB-T network can be designed to match the requirements of the network operator, finding the right balance between robustness and capacity. Networks can be designed to deliver a whole range of services: SDTV, radio, interactive services, HDTV and, using multi-protocol encapsulation, even IP datacasting.
One final technical aspect of DVB-T worth mentioning is its capacity for Hierarchical Modulation. Using this technique,two completely separate data streams are modulated onto a single DVB-T signal. A “High Priority” (HP) stream is embedded within a “Low Priority” (LP) stream.Broadcasters can thus target two different types of receiver with two completely different services. For example, DVB-H mobile TV services optimized for more difficult reception conditions could be placed in the HP stream, with HDTV services targeted to fixed antennas delivered in the LP stream.
Technical Features
DVB-T has technical characteristics that make it a very flexible system: