1、CENELEC EN*hl079-3 93 3404583 0359363 31f5 I I I BRITISH STANDARD Methods of measurement on receivers for satellite broadcast transmissions in the 12 GHz band Part 3. Electrical measurements of overall performance of receiver systems comprising an outdoor unit and a DBS tuner unit The European Stand
2、ard EN 61079-3 : 1993 has the status of a British Standard UDC 621 396 67 620 1 621 317 3 083 BS EN 61079-3 : 1995 IEC 1079-3 : 1993 CENELEC EN*b107%-3 93 H 34045833593b4 251 = Amd. No. Date O BSI 1995 BS EN 61079-3 : 1995 Text affected Committees responsible for this British Standard The preparatio
3、n of this British Standard was entrusted to Technical Committee EPL/12, Radiocommunication, upon which the following bodies were represented: British Broadcasting Corporation British Educational Equipment Association British Radio and Electronic Equipment Manufacturers Association British Rlecommuni
4、cations plc Consumers Association Institution of Electrical Engineers International Consumer Electronics Association Radio, Electrical and Elevision Retailers Association Radiocommunications Agency The following BSI references relate to the work on this standard: Committee reference EPL/12 Special a
5、nnouncement in BSZ Naos September 1993 ISBN O 580 24394 X CENELEC ENxb1079-3 93 = 3404583 0159165 198 BS EN 61079-3 : 1995 Contents page Committees responsible Inside front cover National foreword ii Fore word 2 7kXt of EN 61079-3 3 i CENELEC EN*b1079-3 93 3404583 OL59Lbb 024 BS EN 61079-3 : 1995 Na
6、tional foreword This Part of BS EN 61079 has been prepared by Echnical Committee EPL/12 and is the English language version of EN 61079-3 : 1993 Methods of measurement on receivers for satellite broadcast transm2ssions in the 12 GHz band Part 3: Electrical mclsurm of overall pMormance of receiver sy
7、stems comprising an outdow unit and a DBS tuner unit, published by the European Committee for Electrotechnical Standardization (CENELEC). It is identical with IEC 1079-3 : 1993, published by the International Electrotechnical Commission (IEC). BS EN 61079 is a multipart standard. The other Parts pub
8、lished to date are: Part 1 : 1995 Part 2 : 1995 part 5 : 1995 Radio-frequency measurements on outdoor units Electrical meclsur- on DBS tuner units Electrical measurements on decoder units for MAC/packet syslstems This Part of BS EN 61079 defines the conditions and methods of measurement of overall p
9、erformance of receiver systems comprising an outdoor unit and a DBS tuner unit for the direct reception of satellite broadcast transmissions in the 12 GHz band. The channels are those defined by WARC BS-77 and RARC SAT-83 and the systems are those defined in CCIR Recommendation 650. Performance requ
10、irements are not specified. This Part of BS EN 61079 is intended to be used in conjunction with BS 5876 : 1980 and BS EN 61079-1 : 1995 and BS EN 61079-2 : 1995. Cross-references Publication referred to IEC 107-1 : 1977 Corresponding British Standard BS 3549 Methods of measuring and expressing the p
11、erformance of television receivers Part 1 : 1979 General considerations and electrical memrmnts other than those at audio-frequencies BS 5876 : 1980 Guide for subjective viewing tests for television receivers BS EN 61079 Methods of meclsurement on receivers for satellite broadcast transm2ssions in t
12、he 12 GHz band EN 61079-1 : 1993 Part 1 : 1995 Radio-frequency measurements on outdoor (IEC 1079-1 : 1992) units EN 61079-2 : 1993 Part 2 : 1995 b) carrier signals modulated by the test signals for the system in use. Unless otherwise specified, the carrier frequencies shall be selected from the nomi
13、nal frequencies of the satellite broadcast channels, as specified by the standards of the country or countries for which the equipment under test was designed. CENELEC EN*bL079-3 93 340Y583 OL59I173 2bY Page 7 EN 61079-3 : 1993 3.3.2 Radio-frequency input arrangement Depending on the input facilitie
14、s of the equipment under test, the radio-frequency input signal can be applied in the following way: a) direct signal input to the SHF converter by means of a waveguide or a coaxial cable; b) radiated signal input to the receiving antenna by means of a transmitting antenna. (For detail, see part 1,
15、2.2.4.) 3.3.3 Input signal levei In the case of direct signal input to the SHF converter, the input signal level shall be expressed in terms of available power dB (mW) at the output of the signal generator, including its associated network. In the case of radiated signal input, the input signal leve
16、l shall be expressed in terms of power flux density dB (W/m*) at the aperture plane of the receiving antenna. (For detail, see part 1, 2.2.5.) 3.3.4 Setting of input signal level input signal levels shall be specified for unmodulated carriers, even when modulated carriers are used. The level setting
17、 can be made with a spectrum analyser. 3.4 Reference signals 3.4.1 Reference video signal For the measurements of noise and interference, a composite sine-wave signal specified in 2.2.1 of pari 2 shall be used. Its sine-wave frequency is set at the frequency (f,) shown in table 1. The frequency (f,)
18、 corresponds to the O dB crossover frequency of the pre-emphasis network. 3.4.2 Reference audio signai a) Digital sub-carrier/NTSC system A 1 kHz sine-wave signal at a level corresponding to full scale minus 18 dB in digital coding shall be used. b) MAC systems A data burst carrying a pseudorandom b
19、inary sequence shall be used. CENELEC ENxbL079-3 93 3404583 OL.59174 LTO Page 8 EN 61079-3 : 1993 3.5 Standard measuring conditions Unless otherwise specified, the following conditions apply: a) Audio input signal: none b) Digital sub-carrier in the Digital sub-carrier/NTSC system: off c) Energy dis
20、persal signal: d) MAC system data burst: The data burst includes sync information. none present The input signal is applied to the outdoor unit by the arrangement specified in 3.3.2 and the video output signal is measured through a low-pass filter specified in 3.6. 3.6 Measuring instruments 3.6.1 Te
21、st signal generator The test generator shall be capable of providing baseband video signals as specified in 3.2. For Digital sub-carrier/NTSC signais, a suitably modulated sub-carrier shall also be included. For MAC test signals, when data burst is included, it shall include line syn- chronization a
22、nd a pseudo random binary sequence. 3.6.2 RF modulator The RF modulator shall be capable of frequency modulating the carrier of each broadcast channel in the 12 GHt band with the baseband signal provided by the test signal generator in accordance with the system tested. It should have a maximum outp
23、ut level of -40 dB (mW) or more and provide an onoff switch for an energy dispersal signal. Notional block diagrams of the modulators are shown in figure 1 The noise contribution of the signal source consisting of the r.f. modulator and the test signal generator may affect the measured results. To a
24、void this effect, the carrier to noise ratio of th RF signal shall be better than 30 dB at an output level of -40 dB (mw). 3.6.3 C. W. signal generator The C.W. signal generator shall be capable of generating stable radio-frequency signals in the frequency range of 7,8 GHz to 15 GHz with a maximum o
25、utput level of -30 dB (mw). 3.6.4 Bandpass filter See part 2, 2.6.9. CENELEC EN*b3017-3 93 m 3404583 0359375 037 Page 9 EN 61079-3 : 1993 3.6.5 Lowpass filter See part 2, 2.6.10. 3.6.6 Video noise meter See part 2, 2.6.12. 3.6.7 Picture monitor See part 2, 2.6.14. Section 4: Methods of measurement B
26、aseband characteristics that are not described in this section depend almost entirely on the characteristics of the DBS tuner unit in the receiver under test. Therefore, the results of measurements on the unit, made according to part 2 of IEC 1079, can be applied. 4.1 Sensitivity 4.1 .l Introduction
27、 This test measures the signal-to-noise ratio of a video signal at various input signal levels. NOTE - This method gives sensitivity lower than that under actual receiving conditions, because the noise temperature of the signal source is higher than that in the reception of satellite signals. The di
28、fference between the sensitivity obtained by this method and that in the reception of satellite signals under the clear sky condition is usually 2,4 dB to 2.7 dB, which depends upon the noise figure of the receiver under test and the noise temperature of the receiving antenna. 4.1.2 Method of measur
29、ement Measurement shall be made under the following conditions and procedure. Arrangement of the test equipment is shown in figure 2. 4.1.2.1 Measuring conditions a) Test channel: the centre channel in the satellite broadcast band. b) Test signal level: -90 to -70 dB (mW) in 2 dB steps for direct si
30、gnal input; -114 to -94 dB (W/I#) in 2 dB steps for radiated signal input. c) Test video signal: 50 % grey level signal d) Other conditions: standard measuring conditions (see 3.5). CENELEC EN*bL79-3 93 m 3404583 O359376 T73 m Page 10 EN 61079-3 : 1993 4.1.2.2 Measurement procedure a) Apply an unmod
31、ulated RF signal to the receiver under test and set the signal level at one of the values specified above. b) Modulate the RF signal with the test video signal and measure the unweighted signal-to-noise ratio using a video noise meter. c) Repeat a) and b) at the other specified signal levels in the
32、same way. 4.1.3 Presentation of results The results shall be listed in a table or presented graphically. In the case of MAC signals, it should be noted with the results that they refer to the measurement of compressed video signal. 4.2 Truncation noise 4.2.1 Introduction This test subjectively asses
33、ses truncation noise in the picture caused by the presence of fast transitions associated with amplitude peaks at white level in the video signal. in the case of the digital sub-carrier/NTSC system, truncation noise in the sound is also assessed. 4.2.2 Method of measurement Measurement shall be made
34、 under the following conditions and using the following procedure. The arrangement of the test equipment is shown in figure 3. 4.2.2.1 Measuring conditions a) Test channel: the centre channel in the satellite broadcast band. b) Test signal level: -70 dB (mW) for direct signal input; -94 dB (W/m2) fo
35、r radiated signal input. c) Video test signal: For NTSC system: 0 1 ps pulse on O % grey level signal and 0 1 ps pulse on 50 %, grey level signal. In both cases, the peak level of the signal shall be variable over the range of 90 %to 140 %. For MAC systems: under consideration. d) Digital sub-carrie
36、r: present (Digital sub-carrier/NTSC system only). e) Audio test signal: reference audio signal (Digital sub-carrier/NTSC system only). f) Energy dispersal signal: on g) Other conditions: standard measuring conditions (see 3.5). CENELEC ENubL079-3 93 3YOY583 0359377 90T = Page 11 EN 61079-3 : 1993 4
37、.2.2.2 Measurement procedure a) Apply an unmodulated RF signal to the receiver under test and set the input signal level at the specified value. b) Modulate the RF signal at 90 % peak value with 1 ps pulse on 50 Yo grey level and in the case of the Digital sub-carrierlNTSC system with the reference
38、audio signal. c) Increase the peak level of the modulating video signal gradually up to 140 % and note the amplitude at which truncation noise is just perceptible on the picture monitor. In the Digital sub-carrier/NTSC system, also note the amplitude at which truncation noise is just perceptible in
39、the sound output. d) Repeat a) to c) with the grey level of the video signal set to O Yo. 4.2.3 Presentation of results The results shall be listed in a table. For precise results, the assessment conditions under CCIR Recommendation 500-4 (51 should be observed (see also IEC 569). 4.3 Spurious respo
40、nse 4.3.1 Introduction This test measures response of unwanted signals, excluding those in co-channels, or in adjacent, next adjacent and image channels. It also checks internally generated interference. The measurement is made by applying the wanted and unwanted signals to the receiver under test s
41、imultaneously and measuring the level of the unwanted signal relative to that of the wanted signal to give just perceptible interference on the picture. 4.3.2 Method of measurement Measurement shall be made under the following conditions and procedure. The arrangement of the test equipment is shown
42、in figure 4. 4.3.2.1 Measuring conditions a) Test channels: the lowest, the centre and the highest channels in the satellite broadcast band. b) Unwanted signal frequencies: 7,8 GHz to 15 GHz. c) Test signal level: Wanted signal: -70 dB (mW) for direct signal input; -94 dB (W/m2) for radiated signal
43、input. less than -40 dB (mW) for direct signal input; less than -64 dB (W/m2) for radiated signal input. Unwanted signal: CENELEC EN*bL079-3 93 3404583 OL59L78 84b Page 12 EN 61079-3 : 1993 d) Test video signal: Wanted signal: Vertical Interval Reference (VIR) signal for Digital sub-carrier/NTSC and
44、 colour bar signal for MAC. Unwanted signal: none. e) Other conditions: standard measuring conditions (see 3.5). 4.3.2.2 Measurement procedure a) Apply the wanted RF signal modulated with a 50 % grey level signal to the receiver under test at the input signal level specified above. b) Observe the pi
45、cture with a picture monitor with a decoder connected to the output of the DBS tuner unit. If internally generated interference is observed, note the fact. c) Change the modulation signal to that specified above and add the unwanted signal through a power combiner. d) Observe the picture changing th
46、e frequency and level of the unwanted signal. e) If interference other than that described in b) is observed, note the frequency and the level at which the interference becomes just perceptible. f) Calculate the interference ratio by the level difference between the wanted signal and the unwanted si
47、gnal at the RF input. 9) Repeat a) to f) at other wanted channels. 4.3.3 Presentation of results The results shall be listed in a table and/or presented graphically. 4.4 Differential gain and dffferential phase characteristics with respect to the chrominance sub-carrler 4.4.1 Introduction This test
48、measures the differential gain and differential phase characteristics of the composite colour signal at the output. This test only applies to the Digital sub-carrier/NTSC system. NOTE - If impedance mismatching exists between the SHF converter, the DBS tuner unit and their oonnecting cable, it tends
49、 to cause degradation of the differential gain and differential phase characteristics of the signal in the Digital sub-canierlNTSC system. 4.4.2 Method of measurement Measurement shall be made under the following conditions and procedure. The arrangement of the test equipment is shown in figure 5. Page 13 EN 61079-3 : 1993 4.4.2.1 Measuring conditions a) Test channel: the centre channel in the satellite broadcast band. b) Test signal level: -70 dB (mW) for direct signal input; -94 dB (W/m2) for radiated signal input. c) Test video signal: ten riser staircase signals at 10 Yo, 50 % and
