DIGITAL DATA TRANSMISSION SYSTEM WITH DIFFERENT COMPRESSION RATES, IN PARTICULAR FOR DIGITAL RADIO BROADCASTING

摘要

In digital video broadcasting, data for standard devices are transmitted in the MPEG2 format. In the standard device a standard MPEG decoder decodes the data. An image is generated on the screen with 720 x 576 image spots. However, the expensive standard MPEG decoder and also a filter are needed even for a screen with only 320 x 273 image spots, e.g. a 5" display. In order to dispense with the expensive standard MPEG decoder and the filter, in a first solution the same information with different bit or compression rates adapted to the data reception system is transmitted by the data transmission system (S) to the data reception systems (E1, ..., En) over several transmission channels (K1, ..., Kn). In a second solution, the bit rate of the data generated by a data source (PL) is converted into a lower bit rate by means of a bit rate converter (BRU) before being fed into a channel. Data transmission systems in which data reception systems of different standards receive data from a data transmission system.