1、BRITISH STANDARD Methods of measurement on radio receivers for various classes of emission Part 4. Receivers for frequency-modulated sound broadcasting emissions IS EN iO315-4 : 1998 EC 60315-4 : .997 The European %dard EN 60315-4 : 1998 has the status of a British Standard ICs 33.160.20 NO COPYING
2、WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGH LAW STD.BS1 BS EN b0315-4-ENGL 1998 m bb24bb9 Ob94205 b2b m BS EN 60316-4 : 1998 This British Standard, having been prepared under the direction of the Electrotchnicai Sector Board, was pubiished under the authorim of the Standards Board and com
3、es into effect on 15 Apd 1998 National foreword “his British Standard is the English language version of EN 60315-4 : 1998. It is identical with IEC 60315-4 : 1997. The UK participation in its preparation was entsusted by Technid Committee EPU10, Audio, video and multimedia systems and equipment, to
4、 Subcommittee EPUlWl, Receiving equipment, which has the responsibility to: - aid enquirers to undeistand the text; - present to the responsible intedonai/Empean committee any enquiries on the interpretation, or proposals for change, and keep the UK inter- informed; - monitor related international a
5、nd European developments and promulgate them in the UK. A list of organkations represented on this subcommittee can be obtained on request to its secrehy. From 1 January 1997, ali IEC publications have the number 60000 added to the old number. For instance, IEC 27-1 has been renumbered as IEC 60027-
6、1. For a period of time during the change over fiom one numbering system to the other, publications may contain identifers from both systems. Cross-references Attention is dram to the fad that CEN and CENELEC standars nody include an annex which lists nonnative references to international publicatio
7、ns with their corresponding European publications. “he British Stank this is especially true for the unwanted transmitter. The line-up procedure therefore should be carried out very carefully. The deviation of the signal shall be adjusted by means of the arrangement shown in figure 6. The meter V1 s
8、hall be a quasi-peak voltmeter (see annex A of IEC 60315-1). To obtain the required deviation conditions, the switch S4 is placed in position 1 and the modulation at 500 Hz from the audio-frequency generator adjusted to 132 kHz (121,3 kHz) deviation. The meter reading is noted. The switch S4 is then
9、 placed in position 2 and the noise modulation adjusted to give the same reading on the quasi-peak meter. NOTE - The deviation with 500 Hz modulation should be checked with a deviation meter unless the deviation meter, if any, included in the signal generator is known to be accurate. 1.4.2.4 Standar
10、d modulating signal This is the base-band signal with standard modulating frequency (see 1.4.2.2) and standard value of deviation (see 1.4.2.1). In case of stereophonic mode measurements, a pilot tone signal with the standard deviation shall be included. - STD.BSI BS EN 60315-4-ENGL 1998 W 1624669 0
11、694236 407 = Page 11 EN 60315-4 : 1998 Band coverage MHz 1.4.2.5 Standard carrier frequencies The standard carrier frequency depends on the frequency allocation(s) for f .m. broadcasting in the region where the receiver is to be used. Receivers within the scope of this standard usually cover the ban
12、ds given in table 3. For these bands, the standard measuring frequencies are shown in the table. Standard measuring frequency M Hz 65, to 73,O 76,O to 90,O 873 to 104.0 69 03 94 I 87,5 to 108,O -1 98 1.4.2.6 Standard radio-frequency test signal The standard radio-frequency test signal is a signal at
13、 the appropriate standard carrier frequency (see 1.4.2.5), modulated with the standard modulating signal (see 1.4.2.4). The available power from the source, at the receiver antenna terminais, shall be 70 dB(fW) (equal to 40 dB(pW). 1.4.2.7 Standard radio-frequency input arrangements a) Antenna simul
14、ation networks (artificial antennas) Whereas the rated source impedances of signal sources for measurement purposes (signal generators, etc.) are usually resistive and well-defined, the source impedances of antennas have a wide range of values and are neither resistive nor independent of frequency.
15、It is often necessary, therefore, to insert between the signal source and the receiver input an antenna simulation network which matches the signal source correctly and presents to the receiver a source impedance simulating that of the appropriate antenna. Requirements for antenna simulation network
16、s and examples are detailed in IEC 6031 5-1. Measurements on receivers with external antenna terminals should be made using a signal generator whose rated output impedance is the same as the rated input impedance of the receiver. Antenna substitution networks, and combining networks for the injectio
17、n of more than one signal, should match the appropriate impedance at both ends, so as to allow insertion loss to be defined accurately. Networks with minimum insertion loss should be used while minimizing intermodulation between multiple signal sources. Figure 7 gives simple and practical examples w
18、hich are suitable for use with signal generators that have a 50 Q output impedance. b) Balanced inputs Certain f.m. broadcast receivers are equipped with a balanced antenna input circuit, usually with a rated characteristic impedance of 240 a or 300 0. Such receivers shall be measured with an impeda
19、nce-matched, balanced signal source. Where a balanced source is not available, a balun transformer may be used, allowing for its insertion loss. Care shall be taken that impedance matching is preserved throughout the circuit between the signal source and the antenna terminals of the receiver. STD.BS
20、I ES EN b0315-4-ENGL 1998 Lb24bb9 0694237 343 = Page 12 EN 60315-4 : 1998 1.4.2.8 Standard measuring conditions A rebeiver is operating under standard measuring conditions when: a) the power supply voltage and frequency are equal to, or within the range of, the rated b) the standard radio-frequency
21、test signal is applied via the appropriate artificial antenna to c) the audio-frequency output terminals for connection to loudspeakers, if any, are connected d) the receiver is tuned to the applied signal according to 1.4.4.2; e) the volume control, if any, is adjusted so that the output voltage at
22、 the main audio-frequency output terminals is 1 O dB below the rated distortion-limited output voltage. Measurements may also be made at other stated values of output voltage or power; NOTE - If, during the course of measurement, the a.f. output voltage rises to approach the rated output voltage, it
23、 is essential to adjust the volume control so that the a.f. amplifier is not driven into overload distortion. Such adjustments should be reported with the results. f) the environmental conditions are within the rated ranges; g) for stereo receivers, the balance control or its equivalent, if any, is
24、adjusted so that the output voltages of the two channels are equal; h) the tone controls, if any, are adjusted for the flattest possible audio-frequency response (e.g. for equal response at 100 Hz, 1 kHz and 10 kHz); i) the automatic frequency control (AFC) is inoperative, if this can be achieved by
25、 means of a user control; NOTE - Where a user control of automatic frequency control operation is provided, measurements should be made both with the automatic frequency control off (which will allow easy analysis of the results), and with automatic frequency control on (which represents the situati
26、on when the receiver is in normal use). The two sets of results should be clearly identified. If the automatic frequency control cannot be made inoperative by means of a user control, it may nevertheless be necessary (or desirable) for the automatic frequency control to be disabled for certain measu
27、rements. In this case the automatic frequency control should be disabled by temporarily modifying the receiver, the action taken being detailed with the results (see 1.4.4.1). j) the muting control, if any, is in the muting off position. values ; the antenna terminals of the receiver; to audio-frequ
28、ency substitute loads; 1.4.3 Power supply and relevant measuring conditions 1.4.3.1 Types of power supply The receiver under test shall be operated by the type of power supply specified by the manufacturer. Some receivers are designed to be operable by more than one type of power supply. Methods of
29、measurement of receiver characteristics relating to the type of power supply are detailed in IEC 60315-1. 1.4.4 Tuning 1.4.4.1 Effect of automatic frequency control All tuning operations shall be carried out, having made arrangements to render the automatic frequency control inoperative, if this is
30、possible, except when the performance of the auto- matic frequency control is being investigated. When provision is made for the user to render the automatic frequency control inoperative, measurements may be made both with the automatic frequency control in operation and disabled. The results shall
31、 clearly show whether the automatic frequency control was in operation or not. STD.BSI BS EN 60315-Y-ENGL 1998 Lb24bb9 Ob94218 28T Page 13 EN 60315-4 : 1998 1.4.4.2 Preferred tuning method If the receiver has a tuning indicator, the receiver shall be tuned according to the manufacturers instructions
32、 on the use of the indicator: this corresponds to the way that the receiver is tuned when in use. If there is no tuning indicator, or the tuning indicator does not function correctly, the receiver shall first be tuned approximately to the signal and the audio output signal observed on an oscilloscop
33、e. The deviation shall then be increased until the audio signal becomes distorted, and the receiver shall be tuned for symmetrical clipping of the audio signal, the volume control, if any, being adjusted to prevent overload of the audio-frequency pari of the receiver from occurring . If an alternati
34、ve method of tuning is used, this shall be stated with the results. 1.5 General notes on measurements 1 S.1 Values for voltage and current Unless otherwise stated, the terms voltage, current and so on refer to root mean square (r.m.s.) quantities. 1.5.2 Audio-frequency measurement techniques The cha
35、racteristics of devices such as loudspeakers and audio-frequency distribution lines, for the connection of which output terminals are provided on receivers, are defined (for example, in IEC 60268-1) in terms of constant input voltage rather than constant input power. This applies not only to audio-f
36、requency outputs but also to other outputs, for example intermediate- frequency outputs and multiplex signal outputs. For this reason, it is at present accepted practice to make most measurements at output terminals in terms of the voltage across a substitute load. From this voltage, the power in th
37、e load may be calculated, if required, according to the following formula: where the suffix 2 refers to output terminals as opposed to input terminals. Where the output signal is a substantially pure sine wave (with less than 10 % noise and distortion content), measurements may be made with an avera
38、ge-reading meter scaled in r.m.s. values for sinusoidal input. Under any other conditions, a true r.m.s. meter shall be used, unless otherwise stated. Where several pairs of output terminals are provided, the manufacturer shall state for each pair: a) the rated value of the substitute load, (see IEC
39、 60315-1); b) whether the pair of terminals shall be or shall not be connected to a substitute load when measurements are made at another pair of terminals. NOTE - It is usual to connect all terminals intended for loudspeakers to substitute loads for all measurements, while pairs of terminals for ot
40、her devices are loaded only when measurements are made at those terminals. STD.BSI BS EN 60315-4-ENGL 1998 m 1624669 0694219 116 m Page 14 EN 60315-4 1998 1.5.3 Presentation of radio-frequency signal level or voltage Radio-frequency signai levels may be stated as dB(fW), dB(pW), dB(mW) or e.m.f. in
41、microvolts with stated source or load impedance. The relationship among these values is given in table 4. Table 4 - Presentation of radio-frequency signal level or voltage 1 S.4 Climatic and environmental conditions For information on environmental conditions, reference shall be made to section one
42、of IEC 60315-1. Measurements and mechanical checks may be carried out at any combination of temperature, humidity and air pressure within the limiting values specified in IEC 60315-1. Furthermore, to prevent unnecessary disturbance from external interfering signals, it is desirable to carry out the
43、measurement in a screened enclosure or room, (see also lEC.60315-3). 1 S.5 Preconditioning and preliminary measurements Before recording the results of measurements, the receiver under test should be maintained for at least 10 min in the state of standard measuring conditions, (see IEC 60315-1). As
44、the results of the various measurements described in this part may be influenced by other properties of the receiver, the related measurements given in IEC 60315-1 (if applicable) should normally be carried out first. 1 S.6 Test equipment and accuracy of measurements In general, this standard calls
45、for the use of the simplest test equipment that gives acceptably reliable results. This does not preclude the use of more complex equipment which can be shown to produce the same, or more reliable, results. STD.BSI BS EN 60315-4-ENGL 1998 1624669 0694220 934 Page 15 EN 60315-4 : 1998 For information
46、 on the accuracy of measuring instruments, the presentation of results and deviations from the recommended methods, reference shall be made to section one Of IEC 60315-1. Care should be taken to ensure that any possible shift of the mean carrier frequency due to modulation is sufficiently small to a
47、void affecting the measurements. 1.5.7 Rated values In this pari the term rated is used in the special sense of the value specified by the manufacturer. This term is used when describing rated conditions and rated values of characteristics. 1.5.7.1 Rated conditions To define the conditions under whi
48、ch the performance of the receiver is specified and shall be tested, the manufacturer shall state the following values: - rated power supply voltage(s) and frequency (or frequency range); - rated characteristic impedance of the r.f. signal input (where applicable); - rated value of the substitute lo
49、ad (for each pair of output terminals) (see 1.4.1.2); - rated total harmonic distortion at which the rated (distortion-limited) output voltage or power is specified; - rated environmental conditions (ranges of temperature, pressure and humidity). These values, by their nature, cannot be determined by measurement. 1.5.7.2 Rated values of characteristics The climatic and environmental conditions given in 1 S.4 and the electrical conditions given in 1.5.7.1 enable the manufacturer to specify, and the testing authority to verify, the performance characteristics of the
