1、-1- QUESTION ITU-R 127/6 Mitigation techniques required for the use of digital modulation in the “26 MHz” broadcasting band for local coverage (2007) The ITU Radiocommunication Assembly, considering a) that the band 25 670-26 100 kHz (herein called the “26 MHz band”), is exclusively allocated to the
2、 broadcasting service; b) that this 26 MHz band comes under the provisions of RR Article 12 which includes an informal coordination procedure; c) that this 26 MHz band is not heavily utilised for transmissions using analogue modulation as: availability of suitable receivers capable of receiving this
3、 band is limited; periods of propagation that support reliable long distance transmission in this band may be limited (sunspot cycle, seasonal, diurnal); d) that the system described in Annex 1 of Recommendation ITU-R BS.1514-1 is recommended for use in the 26 MHz band; e) that recent experimental b
4、roadcasting for digitally modulated transmissions using the system described in Annex 1 of Recommendation ITU-R BS.1514-1 have been demonstrated to provide local coverage similar to that achieved at Band II (VHF FM); f) that relevant protection ratios are contained in Recommendation ITU-R BS.1615; g
5、) that the signals require RF bandwidths of 10 kHz for parametric stereo, and 20 kHz for full stereo; h) that transmit antennas have been designed that support local coverage; j) that, nevertheless, there is concern that unwanted skywave emissions may cause harmful interference to other stations on
6、the same frequency using the “26 MHz band” for local coverage, - 2 - decides that the following Question should be studied 1 What are the appropriate mitigation techniques, such as average power and antenna radiation characteristics applicable for the use of digitally modulated emissions in the “26
7、MHz band” for local broadcasting, recognizing the possibility of long distance harmful interference to other stations? 2 What are the coordination requirements in order to provide a reliable local service for each station? further decides 1 that the results of the above studies should be included in a Recommendation and/or Report; 2 that the above studies should be completed by 2010. Category: S2
