1、CCIR RECMN*726-3 93 D 4855232 0520863 602 D Rec. ITU-R S.726 1 SECTION 4B: SYSTEMS ASPECTS - PERFORMANCE AND AVAILABILITY 4B 1 : Systems aspects RECOMMENDATION ITU-R 5.726-1* MAXIMUM PERMISSIBLE LEVEL OF SPURIOUS EMISSIONS FROM VERY SMALL APERTURE TERMINALS (VSAT) (Questions ITU-R 23/4 (1986) and IT
2、U-R 25/4 (1982)* (1992-1993) The ITU Radiocommunication Assembly, considering that it is necessary to protect other terrestrial and satellite radio services from the operation of VSAT earth that it is necessary to protect the transmissions of satellite services on the same satellite as the VSAT that
3、 the number of VSAT earth stations may increase significantly as their popularity grows; that unreasonably stringent values for spurious emissions could hinder the increase in popularity; that some VSAT earth stations are receive-only earth stations and others are transmit-receive earth stations; th
4、at at any given time most transmit-receive VSAT earth stations will be receiving and not transmitting that spurious frequencies from VSAT networks operating at different frequencies are usually different so that that the spurious emission from carrier-off state VSATs is greatly suppressed since a ca
5、rrier-on/off switch is that CISPR Publication 22 (1985) specifies the limits and methods of measurement of radio interference that the carrier close-in spurious emissions and harmonics are more difficult lo suppress than other spurious a) stations; b) services; C) d) e) 0 simultaneously; g) the spur
6、ious emissions will not sum up at the same frequency; h) usually provided in the RF amplifier stage of the VSAT transmitter; j) characteristics of information technology equipment to which the digital processing circuits of the VSATs are similar; k) emissions and hence more precise assessment is nee
7、ded to ensure compatibility with other services, recommends that VSAT earth stations should satisfy the limits for radiated interference field strength specified in CISPR 1. Fublication 22 (1985) applicable to the Class A equipment over the frequency range from 30 MHz to 960 MHz; * * New version of
8、CCIR Recommendation 726. Former CCIR Questions 2314 and 2514. CCIR RECflN*72b-L 93 = 4855232 O520862 547 I 2 Rec. RU-R S.726 2. that outside the band allocated to the fixed-satellite service (FSS) (Earth-to-space) within which the VSAT operating frequency is assigned, the off-axis spurious e.i.r.p.
9、from VSATs shall be below the following limits for off-axis angles greater than 7“: 2.1 carrier-off case (including receive-only VSATs) except for the cases and frequency ranges given in Q 2.3: 960 MHz to 10.7 GHz 10.7 GHz to 21.2 GHz 21.2 GHz to 40 GHz carrier-on case for transmitheceive VSATs exce
10、pt for the cases and frequency ranges given in Q 2.4 and 2.5: 960 MHz to 3 400 MHz 3 400 MHz to 10.7 GHz 10.7 GHz to 2 1.2 GHz 21.2 GHz to 40 GHz exceptions for the carrier-off cases of transmit-receive VSATs which are put into service prior to 1 Janu- 48 dBpW in any 100 kHz band 54 dBpW in any 100
11、kHz band 60 dBpW in any 100 kHz band 2.2 49 dBpW in any 100 kHz band 55 dBpW in any 100 kHz band 61 dBpW in any 100 kHz band 67 dBpW in any 100 kHz band 2.3 ary, 1994: 5 450 MHz to 6 825 MHz 13.6 GHz to 14.9 GHz 26.5 GHz to 3 1.3 GHz exceptions for the carrier-on cases of transmitheceive VSATs which
12、 are put into service prior to 1 Janu- 58 dBpW in any 20 MHz band (for VSATs operating in 6 GHz band) 63 dBpW in any 20 MHz band (for VSATs operating in 14 GHz band) 68 dBpW in any 20 MHz band (for VSATs operating in 30 GHz band) 2.4 ary, 1994: 5 450 MHz to 6 825 MHz 13.6 GHz to 14.9 GHz 28 GHz to 2
13、9 GHz 26.5 GHz to 3 1.3 GHz exceptions for the carrier-on cases of transmiiheceive VSATs which are put into service after 1 Janu- 88 dBpW in any 20 MHz band (for VSATs operating in 6 GHz band) 88 dBpW in any 20 MHz band (for VSATs operating in 14 GHz band) 88 dBpW in any 20 MHz band (for VSATs opera
14、ting in 14 GHz band) 88 dBpW in any 20 MHz band (for VSATs operating in 30 GHz band) 2.5 ary, 1994: 5 450 MHz to 6 825 MHz 13.6 GHz to 14.9 GHz 28 GHz to 29 GHz 26.5 GHz to 3 1.3 GHz 78 dBpW in any 20 MHz band (for VSATs operating in 6 GHz band) 78 dBpW in any 20 MHz band (for VSATs operating in 14
15、GHz band) 78 dBpW in any 20 MHz band (for VSATs operating in 14 GHz band) 78 dBpW in any 20 MHz band (for VSATs operating in 30 GHz band) CCIR RECMN*72b-L 93 4855212 O520863 485 Rec. ITU-R S.726 3 3. assigned, the on-axis spurious e.i.r.p. shall not exceed 4 dBW in any 100 kHz band; that inside the
16、band allocated to the FSS (Earth-to-space) within which the VSAT operating frequency is 4. that the values in this Recommendation be revised to ensure their compatibility with other services. 5. Note 1 - In Q 1, the outdoor unit, the indoor unit and the connecting cable shall be included. For transm
17、it-receive VSAT earth stations the antenna may be removed for this measurement, in which case the transmitter output port shall be terminated by a terminating circuit. Note 2 - According to CISPR Publication 22 (1985) “in some countries the Class A equipment may be subject to restrictions on its sal
18、e or use” because “the Class A limits may be too liberal for domestic establishments and some residential areas”. In order to avoid such restrictions being applied to the sale or use of VSATs, the limits applicable to the Class B equipment should be satisfied in those countries. Note 3 - The worst-c
19、ase off-axis spurious e.i.r.p. can be estimated from the measurement of the input power to the antenna transmission line assuming the antenna gain is 8 dBi or using measured antenna gain data at off-axis angles greater than 7”. Note 4 - Intermodulation and spectral regrowth limits inside the band al
20、located to the fixed-satellite service (Earth-to- space) within which the VSAT operating frequency is assigned are to be determined by the system design, subject to the satellite operator specifications and not covered by this Recommendation. Note 5 - For systems in which the VSAT earth stations are
21、 expected to transmit simultaneously at the same frequency, e.g. for systems employing CDMA, the limits given in 0 3 should be reduced by 10 log N (dB), where N is the maximum number of VSAT earth stations which are expected to transmit simultaneously at the same frequency within the overlapping ban
22、d. Nute 6 - The limit in Q 3 applies to the VSATs operating in the 14 GHz band. The limit for VSATs operating in the 6 GHz and other frequency bands is under study. Note 7 - The on-axis and off-axis spurious e.i.r.p. levels are related by the difference in the on-axis and off-axis antenna gain. Usua
23、lly the off-axis limits in 0 2 are tighter than the on-axis limits in Q 3. that the following Notes should be regarded as part of this Recommendation. Note 8 - For the transmit-receive VSATs operating in the 6 GHz band and put into service before 1 January 1995, the limit of 88 dBpW in any 20 MHz band may be applied instead of the limit in 6 2.2 for the carrier-on case in the frequency range from 4 500 MHz to 5 450 MHz.
