Người dùng liên quan với các liên kết truy cập và sợi quang có dung lượng cao được sử dụng cho các kết nối xương sống. Với sự tiến bộ của xử lý tín hiệu kỹ thuật số (DSP), triển khai phần cứng truyền thống đang được thay thế nhiều hơn và nhiều hơn nữa bởi phần mềm để tăng | 42 Satellite Networking Principles and Protocols Digital video broadcasting DVB Digital video broadcasting DVB technology allows broadcasting of data containers in which all kinds of digital data can be transmitted. It simply delivers compressed images sound or data to the receiver within these containers . No restrictions exist as to the kind of information in the data containers. The DVB service information acts like a header to the container ensuring that the receiver knows what it needs to decode. A key difference of the DVB approach compared to other data broadcasting systems is that the different data elements within the container can carry independent timing information. This allows for example audio information to be synchronised with video information in the receiver even if the video and audio information does not arrive at the receiver at exactly the same time. This facility is of course essential for the transmission of conventional television programmes. The DVB approach provides a good deal of flexibility. For example a 38 Mbit s data container could hold eight standard definition television SDTV programmes four enhanced definition television EDTV programmes or one high definition television HDTV programme all with associated multi-channel audio and ancillary data services. Alternatively a mix of SDTV and EDTV programmes could be provided or even multimedia data containing little or no video information. The content of the container can be modified to reflect changes in the service offer over time . migration to a widescreen presentation format . At present the majority of DVB satellite transmissions convey multiple SDTV programmes and associated audio and data. DVB is also useful for data broadcasting services . access to the World Wide Web . The DVB standards Digital video broadcasting DVB is a term that is generally used to describe digital television and data broadcasting services that comply with the DVB standard . In fact there
