1、- STD-ITU-R RECMN SF-357-4-ENGL 3777 4855232 0530053 304 Rec. ITU-R SF.357-4 1 RECOMMENDATION ITU-R SF.357-4 MAXIMUM ALLOWABLE VALUES OF INTERFERENCE IN A TELEPHONE CHANNEL OF AN ANALOGUE ANGLE-MODULATED RADIO-RELAY SYSTEM SHARING THE SAME FREQUENCY BANDS AS SYSTEMS IN THE FIXED-SATELLITE SERVICE (Q
2、uestions ITU-R 3214 and ITU-R 109/9) (1 963-1 966- 1974-1 978-1 997) The ITU Radiocommunication Assembly, cons idering a) bands above 1 GHz; that systems in the fixed-satellite service (FSS) and line-of-sight radio-relay systems share certain frequency b) absence of frequency sharing; that mutual in
3、terference would increase the noise in both types of system beyond that which would exist in the c) that it is desirable that the noise, due to interference in the telephone channels of existing radio-relay systems, emanating from transmitters of satellites and earth stations, should be a fraction o
4、f the total noise in those systems, such that it would not be necessary to change the design objectives for radio-relay systems, as set out in Recommen- dation ITU-R F.393; d) that it is necessary to speciS, the maximum allowable interference power in a telephone channel, to determine the maximum po
5、wer flux from communication satellites which can be allowed at the surface of the Earth and to determine whether specific locations for satellite-earth stations and terrestrial radio-relay stations would be satisfactory; e) fraction of the total noise power permitted in the hypothetical reference ci
6、rcuit, that a distribution of 1 min mean power, as exemplified in Fig. I, would allot to interference a reasonable recommends 1 that systems in the FSS and line-of-sight analogue angle-modulated radio-relay systems which share the same frequency bands, should be designed in such a manner, that in an
7、y telephone channel of a 2 500 km channel hypothetical reference circuit for frequency-division multiplex, analogue angle-modulated radio-relay systems, the interference noise power at a point of zero relative level, caused by the aggregate of the emission of earth stations and space stations of the
8、 systems in the FSS, including associated telemetering, telecommand and tracking transmitters, should not exceed: 1.1 1 O00 pWOp psophometrically-weighted 1 min mean power for more than 20% of any month; 1.2 50 O00 pWOp psophometrically-weighted 1 min mean power for more than 0.01% of any month, 2 N
9、OTE 1 - The way in which the above values are to be taken into account in the general noise objective for radio-relay systems is defined in Recommendation ITU-R F.393 that the following Notes should be regarded as part of the Recommendation: NOTE 2 - Some administrations may use more stringent perfo
10、rmance objectives for domestic coordination purposes than the preceding values. For international coordination purposes the values given above should be utilized. - - STD-ITU-R RECMN SF.357-4-ENGL 1997 4855212 0530052 2LiO m 2 Rec. ITU-R SF.357-4 FIGURE 1 Example of possible interpolation - 40 - 45 h a O E 8 -50 3 2 m O a .- z - 55 - 60 -t ,O3 i li I I L 0.01 0.1 0.5 1 2 5 10 20 30 405060 70 80 90 95 98 99 1 99.9 99.99 99.5 Percentage of any month 0357-01
