1、STD.CEPT T/R 20-06 E-ENGL L9BB D 232b414 0014bOb 535 D TIR 20-06 E Page 1 Disbibuiion: B Recommendation T/R 20-06 (Puerto de la Cruz 1974, revised at Malaga-Torremolinas 1975, Stockhdm 1976 and 1977) TRANSMITTERS AND RECEIVERS FOR LOW POWER CORDLESS MICROPHONE SYSTEMS Recommendation proposed by the
2、”Radiocommunications” Working Group T/WG 3 (R) Text of the Recommendation adopted by the ”Telecommunications” Commission: “The European Conference of Postal and Telecommunications Administrations, considering (a) that as a result of technical progress, low power radio transmitter-receivers for cordl
3、ess microphone systems are available to the pubiic which enable sound to be transmitted and received without the restrictions which arise from the use of a microphone cable, (b) that the use of such equipment can cause technical, regulatory and legal problems for the Administrations, (c) that it is
4、desirable that the Administrations should establish common technical specifications in order to simpiify such problems, (d) that it would be advantageous both for the Administrations and for the users and manufacturers of cordless microphone systems for those Administrations who so desired to exchan
5、ge type approval test reports, (e) that the aim should be the mutual recognition by the member Administrations of the CEPT of test reports and type approval certificates, recommends 1. 2. 3. 4. 5. 6. that, to the extent that their national regulations permit, the member Administrations of the CEIT s
6、hould plan to adopt rules for the authorisation of low power cordless microphone systems, in accordance with the conditions contained in Annex I to the present Recommendation, that the technical characteristics of low power cordless microphone systems should be those set out in Annex II of the prese
7、nt Recommendation, that the use of “ISM bands and frequency bands used for radio broadcasting should be excluded, that, for type approval tests, the methods of measurement described in Annex III to the present Recommendation should be used. that the test report should contain what is needed for the
8、precise identification of the equipment and for the performance of the tests; to this end the applicant should supply at least the information described in Annex IV to the present Recommendation, which must be communicated at the same time as the test reports are exchanged, that, in preparing test r
9、eports, the Administrations should, as far as possible, follow the order of the tests and numbering of the paragraphs used in Annex IT, and adopt the nomenclatures of Annexes II and of the present Recommendation.” Edition of September 15,1988 STD=CEPT TIR 20-06 E-ENGL 1988 = 232b4L4 00L4b07 471 m T/
10、R 206 E page 3 Annex I CONDITIONS FOR THE USE OF LOW POWER CORDLESS MICROPHONE SYSTEMS 1. The use of low power cordless microphone systems should be authorised as of right (general authorisation); if national legislation 01 regulations do not so permit, individual licences should be granted subject
11、to the least possible restriction. 2. If an individual licence is required. it should be granted without regard to the applicants nationality. 3. A person of a minimum age, determined by the Administrations in accordance with their national regulations must be responsible for the operation of low po
12、wer cordless microphone systems. 4. The equipment used in such cordless microphone systems must be type-approved. 5. The equipment must bear the type-approval number and, where physidy possible, the following information: (a) the manufacturer; (b) thetype; (c) the serial number; (d) the fequency(cie
13、s). 6. All items of equipment supplied in parts and assembled by the purchaser must be type-approved and approved individually. 7. The above-mentioned conditions shall not affect in any manner such national legal provisions as apply to the use of this kind of equipment. Edition of September 15,1988
14、STD-CEPT T/R 20-06 E-ENGL J988 2326414 0014608 308 m T/R 20-06 E Page 4 1. 2. 3. 4. 5. Annex TECHNICAL SPECIFICATIONS FOR LOW POWER CORDLESS MICROPHONE SYSTEMS Frequency bands The appropriate fiqency bands shall be situated between 26.1 and 47 MHz. Multi-channel equipment Multi-channel equipment may
15、 be used in accordance with the conditions indicated in the licence. Class of emission A3E, F3E or G3E Maximum authorised power 1 mW effective radiated power, or 10 mW output power, without modulation. Maximum necessary bandwidth 180 ICHZ 6. trammitter fi-equency error i lokHz 7. Transmitter spuriou
16、s emissions The power of spurious emissions fiom the transmitter shall not exceed 4 nW at any frequency. 8. Receiver spurious emissions The power of spurious emissions fiom the receiver shall not excee 2 nW at any frequency. Edition of September 15,1988 STD-CEPT TIR 20-06 E-ENGL 1988 2326414 0014b04
17、 24q W T/R 20-06 E Page 5 Annex III METHODS OF MEASUREMENT FOR LOW POWER CORDLESS MICROPHONE SYSTEMS 1. 1.1. 1.2. 1.2.1. 1.2.2. 1.2.3. EFFECTIVE RADIATED POWER Definition For the purpose of this specification, and for equipment with an integral antenna, the effective radiated power is the power radi
18、ated in the direction of maximum field intensity under the specified environmental mnditions. Test site and general arrangements Test site The test site shall be located on a surface or ground which is reasonably level. At one point on the Site, a ground plane of at least 5 metres diameter shall be
19、provided. In the middle of this ground plane, a support, capable of rotation through 360“ in the horizontal plane, shall be used to support the test sample at a height of 1.5 metres above the ground. This support shall consist of a plastic tube, filled with salt water (9 grammes NaC1 per litre), whi
20、ch shall have a length of 1.5 metres and an internal diameter of 10 I 0.5 centimetres. The upper end of the tube shall be closed by a meal plate with a diameter of 15 centimetres, which is in contact with the water. The test site shall be large enough to allow the erection of a measuring or transmit
21、ting antenna at a distance fiom the test sample of w2 or 3 metres, whichever is the gteater. The distance actually used shall be recorded with the results of the test carried out on the site. Sufficient precautions shall be taken to ensure that reflections from extraneous objects adjacent to the sit
22、e and ground reflections do not degrade the measurements. Test antenna and receiver The test antenna is used to detect radiation fiom both the test sample and the substitution antenna. It shall be mounted on a support capable of allowing the antenna to be used either horizontally or vertically polar
23、ised and the height of its centre above ground to be varied ova the range 1-5 metres. The receiver shall be capable of being tuned to any frequency under investigation and able to measure the relative levels of signals at its input. Substitution antenna The substitution antenna (c) equipment with no
24、n-rigid external antennae, standing with the antenna extended vertically The transmitter shal be switched on, without modulation, and the test receiver tuned to the operating frequency of the transmitter. The test antenna shall be orientated for vertical polarisation and shail be raised or lowered t
25、hrough the specified height range and the combination of “transmitterltransmitting antenna“ rotated through 360 until the maximum signai is received (l. The combination of “transmitter/transmihg antenna“ is replaced by the substitution antenna, as defined in Clause 1.2.3., and the mput signal of thi
26、s antenna is adjusted in level until a preceding or known related level to that detected from the transmitter is obtained in the test receiver. The effective radiated power shall be quai to the power supplied to the antenna, increased to take account of the substitution antenna gain with respect to
27、the dipole. vertical in normal use perpendicular to the ground; upwards by a nonconducting support. 2. 2.1. TRANSMITER CARRIER POWER Definition For the purpose of this specification, and for equipment provided with output terminals, the carria output power of the transmitter shail be the maximum out
28、put power, without modulation, which fulfils the conditions of these specifications. 2.2. Method of measurement The transmitter shall be connected to a non-reactive, non-radiating load with an impedance equal to that for which the transmitter has been specified and which has been indicated by the ma
29、nufactura. If necessary, an impedance-matching device may be used for testing. The transmitter shall be switched on, without modulation. and the power delivered to the load measured. 3. FREQUENCY ERROR 3.1. Definition The frequency error is the maximum permissible difference between the central freq
30、uency of the frequency band occnpied and the assigned Erequency. For testing, the assigned frequency shall be the transmitters nominal carrier frequency. 3.2. Method of measurement The carrier frequency shall be measured without modulation, with the transmitter connected to a non-reactive, non-radia
31、ting load. A part of the output power shail be coupled to the frequency counter. In the case of equipment with integral antennae, a device for coupling the transmitter output to the frequency counter shall be used. ()This maximum may be a lower vahe than the signal value obtainable at heights outsid
32、e the specified range. Edition of September 15, 1988 T/R 2W E Page 7 The measurements shall be made taking account of simuianeous variation m the ambient tempexahire over one of the following ranges (free choice): -25“ C to +So C; -20“ c to +55“ c; -10“ c to +55“ c; + 5“ c to AO“ c; and of variation
33、 in the supply voltage of I 10% with respect to the nominal value indicated by the manufacturer. The test reports shall specify the range of temperatares chosen. 4. 5. 5.1. 5.2. NECESSARY BANDWIDTH The most favoured frequency, that is, the frequency of the signal which at a given level gives the gre
34、atest frequency deviation, shall be declared by the manufacturer, together with the value of the highest audio frequency transmitted. Two audio signals at the above frequencies shall be applied snccessively to the microphone, with a sound level of 104 dB/2 lo- Pascal at the microphone diaphragm. The
35、 frequency deviation shall be measared for the two cases and the bandwidth (equal to twice the vaiue of the sum of the transmitted audio frequency and the measured frequency deviation) shaii not exceed the necessary bandwidth of 180 kHz. TRANSMITTER SPURIOUS EMISSIONS Definition Spurious emissions a
36、re emissions at frequencies other than those of the carrier and side bands associated with nomal modulation, radiated by the cabinet and chassis of the equipment. For equipment with integral antennae, such emissions include emissions from the antenna. Method of measurement On a test site uiliing the
37、 requirements of Clause 1.2.1. the test sample shall be placed on a non- conducting support at a height of 1.5 metres above the ground. The high frequency power output of the transmitter, where the equipment is fitted with terminals, shall be applied to an appropriately adjusted non-reactive load. U
38、sing a wide-band test antenna and a method similar to that of Clause 1.3., the frequencies up to 2,000 MHz at which the responses to be considered are detected by the measuring receiver shall be recorded. The maximum effective radiated power at each of these frequencies shd be measured using the sub
39、stitution antenna. The test antenna shall be rotated Uirough 90“ to receive signals with horizontal polarisation and the measurement repeated. The higher of the two values shall be the cabinet radiation value for the frequency in question. Edition of September 15,1988 STD.CEPT TIR 20-06 E-ENGL L988
40、= 232b4L4 0014bL2 839 = T/R2-E Page 8 6. 6.1. 6.2. 7. 7.1. 7.2. 8. CONDUCTED SPURIOUS EMISSIONS Definition Conducted spurious emissions are emissions whose power is provided by conduction to the antenna, or to the artincial antenna, at frequencies other than those of the carrier and side bands assoc
41、iated with normal modulation. Method of measurement Conducted spurious emissions shall be measured by connecting the output of the transmitter, working with an unmodulate carrier, to an appropriately adjusted non-reactive, non-radiating load. The measurements shai be made over the range 100 kHz to 2
42、,000 MHz excluding the channel in which the transmitter is intended to operate and the adjacent channels. Measurements of each spurious emission shall be made using a tuned radiation measuring device or a spectrum analyser. The measurements shall be repeated for successive modulation of the transmit
43、ter with the audio signals specified in paragraph 4. RECEIVER SPURIOUS EMISSIONS INCLUDING CONDUCTED SPURIOUS EMISSIONS Definition Spurious emissions horn the receiver are emissions arising on the one hand from emissions supplied to the antenna line and on the other fim emissions radiated by the cab
44、inet and chassis of the For equipment with integral antennae, receiver spurious emissions include both emissions from the antenna and those produced by the cabinet and chassis of the equipment. equipment. Method of measurement The methods of measurement shall be as described in Clauses 5. and 6., su
45、bstituting the receiver for the transmitter. ACCURACY OF MEASUREMENT The tolerances for the measurement of the following parameters shall be as given below: 1. 2. 3. 4. 5. 6. 7. 8. 9. DC voltage AC voltage Radio frequency Radio-frequency voltage Radio-frequency field strength Radio-frequency carrier
46、 power Impedance of artificial loads, combining units, cables, plugs, attenuators, etc. Source impedance of generators and input impedance of measuring receivers Attenuation of attenuators f 3% f 3% f50Hz f2dB f3dE3 f 10% f5% using cells, accumulator, mains supply. - Antennae: nature of antenna term
47、inals; impeaance at antenna terminals; integral antenna: type, length. submitted for type approval and results obtained. - Class of emission: type of modulation. - Operational frequency band of the equipment. - Maximum number of radio channels for which the equipment is designed. - List of carrier f
48、requencies available to the equipment at the time of testing. Transmitter - Nominal effective radiated power or - Nominal output power, Without modulation. - Necessary bandwidth. - Relationship of transmitting frequency to oscillator frequency. Receiver - Frequency changing formula(e). - Number and
49、value of intermediate frequencies. Test conditions - Extreme low temperature. - Extreme high temperature. - Nommal supply voltage(s) Edition of September 15, 1988 STD-CEPT T/R 20-Ob E-ENGL 1988 = 232b414 OOL4bL5 548 = T/R20-06E Appendix, Page 1 Appendix to Recommendation TiR 20-06 This Appendix contains additional information concerning national derogations and options elected for the implementation of Recommendation TIR 20-06. It has been drawn up by the T/GT 3 Working Group on “Radioamimunications“ and distributed by the CEPT liaison office. Since the information has
