RES517 – 327 – MOD RESOLUTION 517 (REV.WRC-15) Introduction of digitally modulated emissions in the high-frequency bands between 3 200 kHz and 26 100 kHz allocated to the broadcasting service The World Radiocommunication Conference (Geneva, 2015), considering a) that digital techniques are being introduced into many existing services; b) that digital techniques allow more effective utilization of the frequency spectrum than double-sideband (DSB) techniques; c) that digital techniques enable reception quality to be improved; d) the relevant parts of Appendix 11 concerning the digital system specification in the HF broadcasting services; e) that ITU-R, in its Recommendation ITU-R BS.1514, has recommended system characteristics for digital sound broadcasts in the broadcast bands below 30 MHz;f) that digital modulation techniques are expected to provide the means to achieve the optimum balance between sound quality, circuit reliability and bandwidth; g) that digitally modulated emissions can, in general, provide more efficient coverage than amplitude-modulated transmissions by using fewer simultaneous frequencies and less power; h) that it may be economically attractive, using current technology, to convert modern conventional DSB broadcasting systems to digital operation in accordance with considering d); i) that some DSB transmitters have been used with digital modulation techniques without transmitter modifications; j) that ITU-R is carrying out further studies on the development of broadcasting using digitally modulated emissions in the frequency bands allocated to the broadcasting service below 30 MHz; k) that a long period could be needed for the introduction of digital broadcasting, taking into account the cost impact of replacement of transmitters and receivers, resolves 1 that the early introduction of digitally modulated emissions as recommended by ITU-R in the HF bands between 3 200 kHz and 26 100 kHz allocated to the broadcasting service is to be encouraged; 2 that digitally modulated emissions shall comply with the characteristics specified in the relevant parts of Appendix 11;