1、1 CCIR VOLUME*IV/ IX-PART82 90 4855232 0500009 3 Rec. 356-4 3 RECOMMENDATION 356-4 MAXIMUM ALLOWABLE VALUES OF INTERFERENCE FROM LINE-OF-SIGHT RADIO-RELAY SYSTEMS IN A TELEPHONE CHANNEL OF A SYSTEM IN THE FIXED-SATELLITE SERVICE EMPLOYING FREQUENCY MODULATION, WHEN THE SAME FREQUENCY BANDS ARE SHARE
2、D BY BOTH SYSTEMS (Questions 32/4 and 17/9) (1963-1966-1970-1974-1978) I The CCIR, CONSIDERING (a) that systems in the fixed-satellite service and line-of-sight radio-relay systems share frequency bands in the range above 1 GHz; (b) that mutual interference would increase the noise in both types of
3、system beyond that which would exist in the absence of frequency sharing; (c) that it is desirable that the noise due to interference in the telephone channels of systems in the fixed-satellite service because of the transmitters of radio-relay systems should, during most of the time, be a small fra
4、ction of the total noise in those systems, as set out in Recommendation 353; (d) that it is necessary to specify the maximum allowable interference power in a telephone channel, to determine the maximum transmitter power and equivalent isofropically radiated power of line-of-sight radio-relay statio
5、ns, and to determine whether specific locations for satellite-earth stations and terrestrial radio-relay stations would be satisfactory; (e) that a distribution of one-minute mean power, as exemplified in Fig. 1 would allot to interference an appropriate fraction of the total noise power permitted i
6、n the hypothetical reference circuit; (f) that systems in the fixed-satellite service may receive interference both through the satellite receiver and through the earth-station receiver, but will receive the higher levels of interference associated with small percentages of time primarily through th
7、e earth-station receivers, UNANIMOUSLY RECOMMENDS. 1. that systems in the fixed-satellite service and radio-relay systems sharing the same frequency bands, be designed in such a manner that the interference noise power, at a point of zero relative level in any telephone channel of a hypothetical ref
8、erence circuit of a system in the fixed-satellite service, caused by the aggregate of the transmitters of radio-relay stations, conforming to Recommendation 406, should not exceed: 1.1 1.2 2. Note - The way in which the above values are to be taken into account in the general noise objective for sys
9、tems in the fixed-satellite service is defined in Note 6 of Recommendation 353. 1000 pWOp psophometrically-weighted one-minute mean power for more than 20% of any month; 50 O00 pWOp psophometrically-weighted one-minute mean power for more than 0.03% of any month. that the following Note should be regarded as part of the Recommendation. , . Y 7 4 Rec. 356-4 0.5 1 2 5 10 20 30 40 50 M) 70 80 90 Percentage of any month FIGURE 1 - Example of possible interpolation I 99.5 9 IO5 i9
