1、 CENELEC EN*b0*315-7 95 3404583 OL73LOL 420 BRITISH STANDARD Methods of Measurement on radio receivers for various classes of emission Part 7. Methods of measurement on digital satellite radio (DSR) receivers The European Standard EN 603157 : 1995 has the status of a British Standard ICs 33.060.30 N
2、O COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITED BY COPYRIGHT LAW BS EN BS 4054 : Part 7 : 1996 60315-7 : 1996 IEC 315-7 : 1995 CENELEC EN*bO*315-7 95 = 3404583 OL73LO2 367 BS EN 60316-7 1996 AmdNo. Date Committees responsible for this British Standard Text affected The preparation of this Britis
3、h Standard was entrusted by Technical Committee EPUl, Audio, video and mdtimedia systems and equipment, to Subcommittee EPUl/l, Receiving equipment, upon which the following bodies were represented: Britbh Broad- Corporation British Educational Suppliers Association British Radio and Electronic Equi
4、pment Manukcturers Association British Telecommunications pic Institution of Electrical Engineem Intedonal Consumer Elecronics Association Radio, Electrid and Television Retailers Association Radiocommunications Agency This British Standard, having been prepared under the direction of the Electrotec
5、hnicai Sector Board, was pubiished under the authority of the Standards Board and comes into effect on 15 June 1996 O BSI 1996 The following BSI references relate to the work on this standard Committee reference EPUl/I Draft for comment 91/03151 DC ISBN O O58 26644 8 -. - - CENELEC EN*b0*315-7 95 =
6、3404583 0373303 2T3 BS EN 60315-7 : 1996 Contents Committees responsible Page Inside front cover National foreword ii Foreword 2 Text of EN 603157 3 O BSI 1996 .I i - - CENELEC EN*b0*315-7 95 = 3404583 OL73LOY L3T = BS EN 60315-7 : 1996 National foreword This British Standard has been prepared by Su
7、bcommittee EPY100/1 and is the English language version of EN 603157 : 1995 Methods of wzeusumt 012 dio receivers for mrous clusses of emission. Part 7: Methods of measurement on digital satellite dio (DSR receivers, published by the European Committee for Electrotechnical Standardization (CENELEC).
8、 It is identical with IEC 315-7 : 1995, including corrigendum : 1995, published by the Intedonal Electrotechnical Commission (IEC), and forms Part 7 of a multi-Part standard on measurement methods on radio receivers. This Part defines conditions and methods for detemiinllig the cmdcs of a DSR tuner/
9、receiver unit to facilitate comparison of measurements made using various methods. Performance requirements are not specified. Cross-references Publication referred to HD 483.3 s2 : 1992 (IEC 2683 : 1988) HD 483.15 S4 : 1992 (IEC 26815 : 1987) HD 560.1 s1: 1990 (IEC 3151 : 1988) EN 60651 : 1994 (IEC
10、 651 : 1979) EN 60958 : 1990 (IEC 958: 1989) Corresponding British Standard BS 6840 Sound sgstem equipment Part 3 : 1992 Methods for sp in this case, the utilization factor shall be clearly stated with the measurement results. NOTE - A standard utilization factor of 90 % was chosen since that value
11、should be as high as possible for a digital transmission system. However, in order to prevent severe distortion in case of small setting errors. the standard utilization factor of 100 % can not be chosen. 3.4 Measurlng instruments 3.4.1 Test signal generator A special test generator which provides a
12、n RF/IF signal according to the system description given in annex A shall be used for the measurements. QPSK modulation by an external baseband signal should be possible (see also 3.4.6). To avoid influence on the measurement results the accuracy of the phase angles of the QPSK modulator should be b
13、etter than 21“. It is assumed that the modulation of the test generator can be switched off (carrier only). 3.4.2 In order to avoid detrimental influence from analogue-digital converters, it is recommended to use a synthetically generated modulation signal which is generated either directly within t
14、he test signal generator or by an external data generator connected via an appropriate interface. Synthetically generated means that audio-signal values (e.g. of a sinusoidal tone), corresponding with the sampling frequency (32 kHz), are calculated theoretically and stored in a memory. These values
15、are fed directly to the encoding net- work. With the exception of some small system-related errors, the modulation of the trans- mitting signal in this case is a theoretically exact signal. Care shall be taken that the relationship between the sampling frequency and the synthesized audio frequency s
16、hould not become a simple integer. Generator for synthesized audio signals CENELEC EN*h*l15-7 75 3404583 01731LL 37T Page 7 EN 60315-7 : 1995 3.4.3 Noise source For measurements with different signal-to-noise ratios, a radio-frequency noise source is needed. In order to obtain a noise power in the r
17、ange of the input power level of the receiver, the noise signal generated by a noise source has generally to be amplified. Care shall be taken that the amplified noise signal represents white noise, at least in the frequency range of the transmitting channel (carrier frequency 17 MHz), .e. the noise
18、 power density shall be constant and noise peaks shall not overload the amplifier. 3.4.4 Input coupling network The DSR receiver may provide the d.c. power supply voltage for the outdoor unit, especially at the input for the first IF. Therefore, the test signal generator or the RF attenuator shall b
19、e equipped with a d.c. decoupling network. If necessary, an appropriate decoupling network has to be inserted. 3.4.5 RF/IF noise-measuring filter The noise-measuring filter is a band-pass filter with a noise-power bandwidth (corresponds to the -3 dB bandwidth of a single tuned circuit) of 16) MHz. N
20、OTE - A small variation (I10 %) of this bandwidth may be permitted. However, this should be taken into account in the evaluation of measurement results. 3.4.6 Data generator/bit error measuring instrument (error detector) Several performance characteristics of a DSR receiver are determined by using
21、a datdbit error measuring device. Generally this device consists of a data generator and an error detector. The data generator is connected, if necessary via an appropriate interface, to the QPSK modulation input of the test signai generator (see figures 8 and 9). The error detector is connected, if
22、 necessary via an interface, to the DSR receiver (see figures 8 and 10) at a test output suitable for bit error measurements (before error correction). NOTE - The interface at the transmitter side inserts synchronization words according to the DSR specification, whereas the interface at the receiver
23、 side stops bit error measuring (stops error detection) during these synchronization words. This is the minimum requirement for the receiver to make synchronization possible. Depending on the decoder strategy of the receiver other measures may be necessary. The data generator provides, corresponding
24、 with the QPSK modulator input of the test signal generator, either two 10,24 Mbit/s bitstreams, or one common 20,48 Mbit/s bitstream, controlled by a clock signal of the test signal generator. A sequence length of d5 -1 bits shall be used. If the same sequence is used to feed both modulation channe
25、ls (A and B), there shall be a time delay of at least 64 bits between the supplied sequences. Corresponding to the signal arrangement at the transmitter side, the error detector measures either separately two bitstreams or one common bitstream. This has to be taken into account in order to get compa
26、rable results. CENELEC EN*bO*315-7 95 3404583 OL73LL2 206 Page 8 EN 60315-7 : 1995 3.4.7 Audio filters and level meters a) Audio band-pass filter For audio-frequency measurements at the audio outputs a band-pass filter for the audiofrequency band shall be used, if not specified otherwise. The pass-b
27、and shall cover the frequency range from 22,4 Hz to 15 kHz. The frequency/amplitude response curve is given in figure 2. The band-pass filter shall be designed in such a way that its inherent noise and/or distortion have no influence on the measurement results. b) Weighting filter level meters For c
28、ertain measurements audio-frequency weighting filters may be used additionally, either - a psophometric filter and a quasi-peak meter having a characteristic according to IEC 315-1, appendix A, which are identical to those specified in ITU-R Recom- mendation BS 468, or - a filter having the so-calle
29、d A-weighting characteristic with tolerances type I as specified for sound level measurements in IEC 651 and a true r.m.s. meter. If one of these filters is used this shall be clearly stated with the measurement results. 3.5 Measuring conditions 3.5.1 Standard measuring conditions A receiver is oper
30、ating under standard measuring conditions when: a) the power supply voltage and frequency are equal to the rate values; b) the standard radio-frequency input signal is applied to the antenna terminals of the receiver (see figure i); c) the audio-frequency output terminals for connection to loudspeak
31、ers (if any) are connected to audio-frequency substitute loads (see figure 1); d) the receiver is tuned to the applied signal as specified by the manufacturer; e) the volume control (if any), is adjusted so that the output voltage at the main audio-frequency output terminals is 10 dB below the rated
32、 distortion limited output voltage; measurements may also be made at other stated vatues of output voltage or power, the power or equivalent voltage shall then be clearly stated with the results; 1) the loudness control (physiologically compensated volume control) (if any) is inoperative; if the com
33、pensation cannot be switched off, measurements shall be carried out with the loudness control set at minimum attenuation, and the utilization factor reduced to avoid overload of the audio-frequency part of the receiver; this shall clearly be stated with the results; g) the environment conditions are
34、 within rated ranges; h) for the reception of stereophonic signals, the balance control or its equivalent (if any) is adjusted so that the output voltages of the two channels are equal; i) the tone controls (if any) are adjusted for the flattest possible audio-frequency response (for example, equal
35、response at 1 O0 Hz, 1 kHz and 1 O kHz). -. ._ ._ - - Page 9 EN 60315-7 : 1995 3.5.2 Setting of RFAF carrier-to-noise ratio For satellite sound broadcasting receivers the radio-frequency input stages and mixers are part of the antenna; therefore there is no need to design the receiver for very low i
36、nput signal levels. Thus a radio-frequency signal with a stated level (see 3.3.1) is used for measurements and the RF/IF carrier-to-noise ratio (UN) is changed by addition of a noise signal. The wanted signal and the noise signai are added in a power combiner, and their signai levels are adjusted by
37、 means of variable radio-frequency attenuators. The circuit arrangement is given in figure 8. Using this arrangement, the wanted signai level and the noise signal level shall be measured separately with a radio-frequency power meter at the output of the band-pass filter according to 3.4.5. For measu
38、ring the wanted signal level, the modulation of the test signal generator shall be switched off (carrier only) and the radio-frequency attenuator for the noise source shall be set to maximum attenuation. For measuring the noise power, the radio-frequency attenuator for the wanted signal shall be set
39、 to maximum attenuation. For the signal which is not measured, an attenuation of 40 dB is considered to be sufficient. The insertion loss of the band-pass filter shall be taken into account. NOTE - Care must be taken that other signals, such as interfering signals or Gaussian noise, which can intrud
40、e in the transmission between signal generator and receiver input, are small enough not to influence the power measurements. Section 4: Methods of measurement based on analogue modulation signals 4.1 Overall total harmonic distortion plus noise as a function of output voltage, modulation frequency a
41、nd dynamic range 4.1 .l Introduction The overall total harmonic distortion is the total harmonic distortion of the audio-frequency output signal, measured with the standard radio-frequency input signal and a specified modulation frequency at the output of the filter according to 3.4.7 a). It is a fu
42、nction of audio-frequency output voltage or power. Apart from distortion, noise is produced in digital transmissions, depending on modulation level. Ultimately, the noise level depends on system parameters (quantizing noise), which during the measurements cannot easily be separated from noise produc
43、ed by the receiver. The theoretical value of quantizing noise relative to maximum modulation is: -84 dB for maximum utilization factor (100 O/.) and -96 dB for a utilization factor of 525 Oh (corresponding to 1-12 dB). The residual noise without modulation may well have values below -100 dB. Since a
44、n essential part of the noise, the quantizing noise, is determined by the system, noise measurements are performed together with the measurements of overall harmonic distortion. From the measurement results the distortion limited output voltage or power and other output characteristics may be determ
45、ined. CHELEC EN*b*315-7 95 = 3404583 0173114 089 W Page 10 EN 60315-7 : 1995 The dynamic range D is the difference between the output level at a utilization factor of 100 ?lo and the level of distortion and noise components (THD+N), measured with the same settings of the controls of the receiver wit
46、h extremely reduced utilization (for example 60 dB). If A is the reduction of the utilization factor in decibels below the maximum utilization factor (100 Oh), then the dynamic range in decibels can be calculated by the following formula: 4.1.2 Method of measurement An example of a circuit arrangeme
47、nt for these tests is shown in figure 1. The receiver is brought under standard measuring conditions (see 3.5.1 and figure l), and the total harmonic distortion plus noise of the audio-frequency output signal at the terminals under consideration is measured. The measurements may be repeated for othe
48、r modulation frequencies within the audio-frequency range. If a volume control is provided, measurements can be made at other settings of this control, and also at other settings of the tone controls. Measurements can also be made with various values of utilization factor up to and including 100 Yo
49、utilization (see 3.3.3). For a utilization factor of O %, corresponding to digital “O“, the idle-channel signal-to-noise ratio is obtained. For the measurement of idle-channel signal-to-noise ratio an audio- frequency weighting filter and level meter according to 3.4.7 b) shall be used. For stereophonic transmission each channel shall be measured separately, with the other channel unmodulated. Measurements may be repeated with both channels modulated at the same frequency. NOTES 1 For these measurements a total harmonic distortion meter is recommended,
