1、lb2Libb 0587151 545 BRITISH STANDARD Methods of measurement for equipment used in digital microwave radio transmission systems Part 3. Measurements on satellite earth stations Section 3.14 Earth stations for satellite news gathering (SNG) c * Kn The European Standard EN 60835-314 : 1996 has the stat
2、us of a British Standard ICs 33.060.30 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHI LAW it should then be confirmed that the received cross-polarized signal level is lower than the level correspond- ing to the specified cross-polarization discrimination. If required, a test sig
3、nal is then transmitted from the SNG terminal to the satellite, under the direction of the cooperating earth station, and the correct antenna alignment of the SNG terminal is verified by confirming that the cross-polarized signal level received by the Co-operating earth station is lower than the lev
4、el corresponding to the specified cross- polarization discrimination. NOTE - This measurement should be carried out at a frequency at which no other cross-polar signal is transmitted. 5.1.3 Carrier frequencies See IEC 835-1 -2. The frequency of the carrier transmitting the vision and sound signals s
5、hall be measured by switching off the modulation. Measurements shall be carried out at specified steps of the frequency-agile up-converter 1, and the deviation between the measured and nominal frequencies shall be ascertained. The microwave counter for this measurement shall be connected to the low-
6、level output of the coupler following the HPA, as shown in figure 2. 5.1.4 RF output power See IEC 835-1-2. A power meter should be connected to the r.f. output port by disconnecting the antenna waveguide. For an SNG terminal with digital modulation, the output power of the carrier shall be measured
7、, and, if required, the mean output power of the signal modulated, preferably by a pseudo-noise bit sequence. For an SNG terminal with analogue modulation, the unmodulated carrier power shall be measured. The range of output power adjustment, if applicable, should also be ascertained. . When multipl
8、e carriers are transmitted simultaneously from a single power amplifier, the power of each carrier shall be measured separately by using a calibrated spectrum analyzer. 5.1.5 RF output spectrum See IEC 835-1-2. With a spectrum analyzer connected to the low-level test output port of the coupler shown
9、 in figure 2, the spectrum shall be measured at the rated output power, with the operational carrier modulated by a suitable test signal. A mask should be applied to the spectrum analyzer screen to ascertain that spectrum lines are confined within specified limits. = lb24bb9 05871bL 479 =- Page 7 EN
10、 60835-3-14 : 1996 5.1.6 Radiation hazards The purpose of this measurement is to ensure that the r.f. electromagnetic fields radiated from the SNG equipment do not constitute a potential hazard to operators, or to the general public. The SNG installation shall be approached from all accessible direc
11、tions, and measurements shall be taken of the power flux density by using a calibrated test antenna connected to a receiver (hazard meter). All locations where a specified power flux density is exceeded shall be identified. 5.1 .? See the future IEC 835-3-13. Off-axis EIRP (equivalent isotropically
12、radiated power) density 5.1.8 G/T of the monitoring system See IEC 835-3-7. The purpose of measuring this parameter is to ascertain that the monitored picture and sound signals characterize, to a sufficient extent, the uplinked picture and sound signals. 5.2 Baseband parameters 5.2.1 Interface param
13、eters of the sound/vision equipment See IEC 835-1-2. 5.2.2 Control functions - antenna alignment, azimuth and elevation. including antenna tracking, if applicable; - polarization; - carrier power; - carrier frequency (by synthesizer tuning); - transmitter output power (onioff). In a basic flyaway sy
14、stem, all these functions may be manually controlled. In an SNG vehicle, some of these functions, for example antenna and polarization adjustments, may be operated by remote control. It should be verified that the above control functions operate as specified. 5.2.3 Video/sound parameters The video a
15、nd sound parameters shall be tested in a transmitterlreceiver loop utilizing the loop test translator shown in figure 2. A test receiver of suitable quality shall be applied if these parameters cannot be accurately assessed in the transmitter/receiver loop because of the insufficient quality of the
16、SNG terminal receiving part. 5.2.4 Duplex sound communication channels These channels shall also be checked in a transmitterlreceiver loop utilizing the loop test translator. A functional check shall be carried out by initiating a call, and verifying that connection with the called party has been es
17、tablished. Page 8 EN 60835-3-14 : 1996 5.3 Power supply system The purpose of testing the power supply system is to confirm, under specified variations of supply input voltage and frequency, relevant performance parameters such as output power, spurious signals, transmit frequency, etc. 6 Reference
18、documents ITU-R Recommendation SNG 770: 1994, Uniform operational and control procedures for satellite news gathering (SNG) ITU-R Recommendation SNG 771 -1 : 1994, Auxiliary coordination satellite circuits for SNG terminals ITU-R Recommendation SNG 722-1 : 1994, Uniform technical standards (analogue
19、) r“3r satellite news gathering (SNG) LbZqbbS 0587363 2b7 Page 9 EN 60835-3-14 : 1996 am aa .- - c L 3 U L a z u) d 5 Page 10 EN 60835-3-14 : 1996 I I 61 - I - u. I i - Lb2Libb 0587Lb5 03T W Page 11 EN 60835-3-14 : 1996 Annex ZA (normative) Normative references to international publications with the
20、ir corresponding European publications This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendme
21、nts to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments). NOTE. When an international publication has been modified b
22、y Common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year IEC 8351-2 1992 IEC 8353-2 1995 IEC 835-3-7 1995 IEC 835-3-13 : 1996 Title Methods of measurement for equipment used in digital microwave radio transmission systems Part 1: Measurements common to terrastrial rad
23、io-relay systems and satellite earth stations Section 2: Basic chamtemstics Section 2: Antenna Part 3: Measurements on satellite earn stations Section 7: Figure-of-merit of receiving systern Ssctwn 13: VSATsystems EN/iD Year EN 608351-2 1993 EN 608353-2 1996 EN 60835-3-7 1995 EN 608353-13 1996 O BSI
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