1、 Rec. ITU-R SM.1539-1 1 RECOMMENDATION ITU-R SM.1539-1 Variation of the boundary between the out-of-band and spurious domains required for the application of Recommendations ITU-R SM.1541 and ITU-R SM.329 (Question ITU-R 211/1) (2001-2002) The ITU Radiocommunication Assembly, considering a) that Rec
2、ommendations ITU-R SM.1541 and ITU-R SM.329 give the definitions of the terms “out-of-band domain” and “spurious domain”, but that these definitions do not precisely specify the boundary between the out-of-band (OoB) and spurious domains; b) that the boundary between the OoB and spurious domains is
3、important for the application of both Recommendations ITU-R SM.1541 and ITU-R SM.329; c) that the boundary between the OoB and spurious domains is, in general, a function of the necessary bandwidth, but may be functions of different parameters other than the necessary bandwidth in certain applicatio
4、ns; d) that the boundary between the OoB and spurious domains may require variations, in particular, for narrow-band and wideband transmissions, as well as for primary radars, noting a) that, according to Recommendations ITU-R SM.1541 and ITU-R SM.329, normally the boundary between the OoB and spuri
5、ous domains is the frequency separated from the centre frequency of the emission by 250% of the necessary bandwidth of the emission (see Note 1), recommends 1 that Annex 1 should be referred to in the case of variation of the boundary between the OoB and spurious domains which may be required for th
6、e application of Recommen-dations ITU-R SM.1541 and ITU-R SM.329. NOTE 1 Recommendation ITU-R SM.1138, which is incorporated by reference into the Radio Regulations (RR), deals with the determination of necessary bandwidth for various emissions. Recommendation ITU-R SM.853 presents additional inform
7、ation concerning the determination of necessary bandwidth for certain emissions, including unmodulated pulse emissions and some digital modulation. In addition, Recommendations ITU-R SM.1541 (recommends 2.3) and ITU-R SM.329 (further recommends 1.4 and 2.3) discuss the necessary bandwidth for certai
8、n emissions for the purpose of determining the boundary between the OoB and spurious domains. 2 Rec. ITU-R SM.1539-1 ANNEX 1 Variation of the boundary between the OoB and spurious domains 1 Introduction As stated in recommends 2.3 of Recommendation ITU-R SM.1541 and further recommends 2.3 of Recomme
9、ndation ITU-R SM.329, the boundary between the OoB and spurious domains, which is generally specified as being separated from the centre frequency by 250% of the necessary bandwidth, needs to be modified for narrow-band and wideband (including multicarrier) systems, and certain other situations. Thi
10、s Annex provides: a set of guidelines on values of bandwidths across the spectrum at which the general definition needs to be varied; and a set of known situations in which additional guidelines are required. 2 Boundary variations for narrow-band and wideband systems For the definition of necessary
11、bandwidth, its applicability to multichannel or multicarrier transmitters/transponders, and its use in the fixed and radiodetermination services, see further recommends 1.4 of Recommendation ITU-R SM.329. Figure 1 shows the spurious boundary as a function of necessary bandwidth, indicating the bound
12、ary variations. The normal separation between the centre frequency and the spurious domain boundary is 250% of the necessary bandwidth, as shown in Fig. 1, between the vertical dashed lines. For some narrow-band emissions, it is appropriate to avoid specifying OoB and spurious domains in very narrow
13、 bandwidths near to the emission, which will usually be under the control of the same operator. On the other hand, it is necessary to restrict the linear growth of the OoB domain versus necessary bandwidth for wideband emissions, in order to restrict the incursion of the OoB domain into adjacent ban
14、ds. Figure 1 shows how the boundary is determined for the narrow-band and wideband cases. When the necessary bandwidth of the emission is less than the lower threshold value BL, the boundary is a constant 2.5 BL. Conversely, when the necessary bandwidth exceeds the upper threshold value BU, the boun
15、dary increases at a lower rate, having a value of 1.5 BN+ BU. Table 1 shows the formulas for the narrow-band, normal and wideband cases. Rec. ITU-R SM.1539-1 3 1539-01BLBUFIGURE 1Spurious domain boundary as a function of necessary bandwidthNecessary bandwidthSpuriousboundary(separationfromcentrefreq
16、uency)Normal case(slope = 2.5)Wideband case(slope = 1.5)Minimumseparation(narrow-bandcase)TABLE 1 It should be noted that Table 1 can apply to asymmetric emissions, since the offset is specified based on the centre of the necessary bandwidth. For situations where the boundary is not defined in terms
17、 of necessary bandwidth, see 3. In the case of narrow-band and wideband systems, the variation of the spurious boundary also affects the OoB masks specified in Recommendation ITU-R SM.1541. This is covered in recommends 5 of Recommendation ITU-R SM.1541. Type of emission Necessary bandwidth (BN) Fre
18、quency separation between the centre frequency and the spurious boundary Narrow-band case BUBU+ 1.5 BN4 Rec. ITU-R SM.1539-1 Table 2 provides guidance for determining general values of separation between the centre frequency of an emission and the beginning of its spurious domain. A minimum separati
19、on applies to the narrow-band case, while the normal and wideband cases have separate formulas for determining the boundary. TABLE 2 Guideline values for frequency separation between the centre frequency and the boundary of the spurious domain Example 1: The necessary bandwidth of an emission at 26
20、MHz is 1.8 kHz. Since 2.5 BN is only 4.5 kHz, the minimum separation applies. The spurious domain begins 10 kHz each side of the centre of the necessary bandwidth. Example 2: The necessary bandwidth of an emission at 8 GHz is 200 MHz. Since the wideband case applies for BN 100 MHz at that frequency,
21、 the spurious domain begins 400 MHz each side of the centre of the necessary bandwidth. Using the general separation formula, the OoB domain would have extended to 2.5 200 MHz = 500 MHz either side of the centre frequency. Narrow-band case (BNBU) Frequency range BLSeparation Normal separationBUSepar
22、ation 9 kHz 26 GHz 1 MHz 2.5 MHz 2.5 BN500 MHz 1.5 BN+ 500 MHzNOTE 1 In Table 2, fcis the centre frequency of the emission. If the assigned frequency band of the emissions extends across two frequency ranges, then the values corresponding to the higher frequency range may be used for the whole assig
23、nment. NOTE 2 For situations in which the above guidelines are not applicable, additional guidelines are provided in 3. NOTE 3 Further studies need to be conducted within the ITU-R to confirm the values of frequency separation in Table 2. Rec. ITU-R SM.1539-1 5 3 Situations where additional guidelin
24、es are required The above guidelines are suitable for general application but specific cases where further guidelines are necessary are given in the following sections. 3.1 Situations where the boundary is not defined in terms of necessary bandwidth Some systems specify OoB emissions relative to cha
25、nnel bandwidth, or channel spacing. These may be used as a substitute for the necessary bandwidth in 2, provided they are found in ITU-R Recommendations. 3.2 Particular service types and bands The values of frequency separation in Table 2 are selected to cover most, but not all situations. Rather th
26、an set those values at the worst case in each range, it is more realistic to use a more stringent value, and list those cases requiring different values separately. Tables 3 and 4 show those cases which have been identified. TABLE 3 Narrow-band variations for systems or services and frequency bands
27、Narrow-band case (BN50 W 80 200(2)Fixed service 1.5-30 MHz PT 50 W 30 75(2)(1)The separation value is based on an assumption that the maximum value of the necessary bandwidth is about 3 kHz for the frequency range 14 kHz-1.5 MHz. The value of 50 kHz separation is extremely large as compared with the
28、 necessary bandwidth. It is because unwanted emissions of high power transmitters under modulated conditions have to be below the spurious limit (70 dBc) at the boundary between the OoB and spurious domains. (2)PT is the transmitter power. The separation values are based on an assumption that the ma
29、ximum value of the necessary bandwidth is about 12 kHz for the frequency range 1.5-30 MHz. The value of 200 kHz separation for PT 50 W is extremely large as compared with the necessary bandwidth. It is because unwanted emissions of high power transmitters under modulated conditions have to be below
30、the spurious limit, 70 dBc, at the boundary between the OoB and spurious domains. Also, if future systems in the fixed service operating in this frequency range require a necessary bandwidth larger than 12 kHz, it may become necessary to review the 200 kHz separation. These separation values were de
31、rived from the Category A spurious domain emission limits in Recommendation ITU-R SM.329. 6 Rec. ITU-R SM.1539-1 TABLE 4 Wideband variations for systems or services and frequency bands 3.3 Primary radars in the radiodetermination and other services According to further recommends 2.3 of Recommendati
32、on ITU-R SM.329, the spurious domain emission generally begins at a frequency separation equal to 250% of the necessary bandwidth, with exceptions for certain kinds of systems, including those with digital or pulsed modulation. RR Appendix 3 includes similar provisions. However, it is difficult to a
33、pply the general boundary concept of 250% of the necessary bandwidth to primary radar stations in the radiodetermination and other services, such as the meteorological aids service, the space research service, and the Earth exploration-satellite service. For the case of primary radar systems the OoB
34、 mask rolls off at 20 dB per decade from the 40 dB bandwidth to the spurious limit specified in Table 2 of Recommendation ITU-R SM.329. The detailed definition of the OoB/spurious domain boundary is contained in Annex 8 of Recommen-dation ITU-R SM.1541. The above specification of the boundary is the
35、 subject of ongoing ITU studies with a design objective of 40 dB per decade roll-off from the 40 dB bandwidth. These studies should be completed before the 2006 Radiocommunication Assembly. Wideband case (BN BU) Service Frequency range BUSeparation Fixed service 14-150 kHz 20 kHz 1.5 BN+ 20 kHz Fixe
36、d-satellite service (FSS) 3.4-4.2 GHz 250 MHz 1.5 BN+ 250 MHz FSS 5.725-6.725 GHz 500 MHz 1.5 BN+ 500 MHz FSS 7.25-7.75 GHz and 7.9-8.4 GHz 250 MHz 1.5 BN+ 250 MHz FSS 10.7-12.75 GHz 500 MHz 1.5 BN+ 500 MHz Broadcasting-satellite service (BSS) 11.7-12.75 GHz 500 MHz 1.5 BN+ 500 MHz FSS 12.75-13.25 GHz 500 MHz 1.5 BN+ 500 MHz FSS 13.75-14.8 GHz 500 MHz 1.5 BN+ 500 MHz
