.rs .\" Troff code generated by TPS Convert from ITU Original Files .\" Not Copyright ( c) 1991 .\" .\" Assumes tbl, eqn, MS macros, and lots of luck. .TA 1c 2c 3c 4c 5c 6c 7c 8c .ds CH .ds CF .EQ delim @@ .EN .nr LL 40.5P .nr ll 40.5P .nr HM 3P .nr FM 6P .nr PO 4P .nr PD 9p .po 4P .rs \v | 5i' .sp 2P .LP \fBRecommendation\ N.13\fR .RT .sp 2P .ce 1000 \fBMEASUREMENTS\ TO\ BE\ MADE\ BY\ THE\ BROADCASTING\ ORGANIZATIONS\fR .EF '% Fascicle\ IV.3\ \(em\ Rec.\ N.13'' .OF '''Fascicle\ IV.3\ \(em\ Rec.\ N.13 %' .ce 0 .sp 1P .ce 1000 \fBDURING\ THE\ PREPARATORY\ PERIOD\fR .ce 0 .sp 1P .PP After the broadcasting organizations have taken possession of the international sound\(hyprogramme connection, they make measurements on the complete connection in the band of frequencies effectively transmitted, from the point where the programme is picked up to the point where the programme is received. .sp 1P .RT .PP The broadcasting organizations should, for their measurements, send from the origin of the international sound\(hyprogramme connection a sinusoidal signal at the reference frequency (800 or 1000\ Hz) only, whose maximum amplitude is 9\ dB below that of the maximum instantaneous voltage that should never be exceeded at this point in the course of a sound\(hyprogramme transmission. .PP The duration of the period during which the signal at this level is sent should be kept as short as possible, for example, of the order of 30\ seconds. If necessary, the ISPCs should verify that the received level at the access point on the international sound\(hyprogramme circuit is equivalent to 0\ dBm0. .PP When it is necessary, either for purposes of fault location or to maintain a watch on the continuity of the circuit, to send a continuous tone, or when making measurements at other frequencies than the reference frequency, the amplitude at the origin of the international sound\(hyprogramme connection should be 21\ dB below the voltage that should never be exceeded at this point during the course of a sound\(hyprogramme transmission. Under these circumstances the level at the access point on the international sound\(hyprogramme circuit is equivalent to \(em12\ dBm0. .PP During the preparatory period a useful signal which can be used for the alignment of sound\(hyprogramme connections is that shown in Figure\ A\(hy1/N.13. The definitions and its method of use are given in Annex\ A of this Recommendation. A suitable automatic measuring equipment for this purpose is specified in Recommendation\ O.33\ [1]. .PP \fINote\fR \ \(em\ The numerical values given above ensure that during the sound\(hyprogramme transmission the peak voltage at a zero relative level point will not exceed that of a sinusoidal signal having an r.m.s. value of 2.2\ volts. .PP The reason for sending the reference frequency only for short durations during this final line\(hyup, at a voltage 9\ dB below the peak voltage is that it is not desirable to subject carrier systems to overloading by continuously transmitting a test signal corresponding to the peak voltage reached only momentarily during the transmission of an actual programme. .RT .ce 1000 ANNEX\ A .FS Based on CCIR Recommendation 661\ [2]. .FE .ce 0 .ce 1000 (to Recommendation N.13) .sp 9p .RT .ce 0 .ce 1000 \fBSignals for the alignment of international sound\(hyprogramme connections\fR .sp 1P .RT .ce 0 .LP A.1 \fIDefinitions\fR .sp 1P .RT .sp 1P .LP A.1.1 \fBsource identification\fR .sp 9p .RT .PP An announcement should be used to identify the originating point of the test signals and should be preferably as short as possible. It is suggested that such an announcement contain at least the following information: .RT .LP \(em name of originating organization; .LP \(em location; .LP \(em country. .PP The sound programme signal should be controlled by the sending broadcaster so that the amplitudes of the peaks only rarely exceed the peak amplitude of the permitted maximum (sine\(hywave test) signal. .bp .sp 2P .LP A.1.2 \fITest signal and level definitions\fR .sp 1P .RT .sp 1P .LP A.1.2.1\ \ \fBalignment signal (AS)\fR .sp 9p .RT .PP Sine\(hywave signal at 1020 Hz at a level of 0\ dBm0s, which is used to align the international sound\(hyprogramme connection. .RT .sp 1P .LP A.1.2.2\ \ \fBmeasurement signal (MS)\fR .sp 9p .RT .PP Sine\(hywave signal at 1020 Hz at a level 12 dB below the alignment signal level, which should be used for long\(hyterm measurements and measurements at all frequencies. .RT .sp 1P .LP A.1.2.3\ \ \fBpermitted maximum signal (PMS)\fR .sp 9p .RT .PP Sine\(hywave signal at 1020 Hz, 9 dB above the alignment signal level, equivalent to the permitted maximum programme\(hysignal level. .RT .sp 2P .LP A.2 \fITest signal format\fR .sp 1P .RT .PP A.2.1 A three\(hylevel sinusoidal test signal at a reference frequency of 1\ kHz should be used to check the alignment of international sound programme connection. These three levels should be combined with the source identification and be repeated cyclically as specified in the format shown in Figure\ A\(hy1/N.13 for monophonic and stereophonic connections. .sp 9p .RT .LP .rs .sp 30P .ad r \fBFigure A\(hy1/N.13, p. 1\fR .sp 1P .RT .ad b .RT .LP .bp .PP A.2.2 Provisionally, the portion of the test signal designated at +9\ dBm0s in Figure\ A\(hy1/N.13 will be replaced by a signal at 0\ dBm0s. The resulting two\(hylevel test signal is required until all transmission systems are capable of carrying sinusoidal signals at +9\ dBm0s without producing excessive channel loading or crosstalk into other channels. .PP A.2.3 Some organizations may not have automatically generated test levels as defined in \(sc\(sc\ A.2.1 and\ A.2.2. In these cases, the alignment level of 0\ dBm0s at 1020\ Hz should be used for the alignment of international sound programme connections. .sp 1P .LP A.3 \fIMeasurement methods\fR .sp 9p .RT .PP The fundamental concept of the test signals is to provide organizations with accurate and well defined levels. These levels are intended to provide rapid identification of level errors as well as to allow operational personnel sufficient time to make the necessary level adjustments at the appropriate points in the international sound programme connection. Alignment of the connection is made by adjusting the alignment signal to the appropriate point on the programme level meter. Identification of left and right channels is provided as shown in Figure\ A\(hy1/N.13. .RT .sp 2P .LP \fBReferences\fR .sp 1P .RT .LP [1] CCITT Recommendation \fIAutomatic equipment for rapidly measuring\fR \fIstereophonic pairs and monophonic sound\(hyprogramme circuits, links and\fR \fIconnections,\fR Vol.\ IV, Rec.\ O.33. .LP [2] CCIR Recommendation \fISignals for the alignment of international\fR \fIsound\(hyprogramme connections,\fR Vol.\ XII, Rec.\ 661, ITU, Geneva,\ 1986. \v'6p' .sp 2P .LP \fBRecommendation\ N.15\fR .RT .sp 2P .ce 1000 \fBMAXIMUM\ PERMISSIBLE\ POWER\ DURING\ AN\ INTERNATIONAL\fR .EF '% Fascicle\ IV.3\ \(em\ Rec.\ N.15'' .OF '''Fascicle\ IV.3\ \(em\ Rec.\ N.15 %' .ce 0 .sp 1P .ce 1000 \fBSOUND\(hyPROGRAMME\ TRANSMISSION\fR .ce 0 .sp 1P .LP \fBGeneral\fR .sp 1P .RT .PP To check that the maximum power transmitted during a sound\(hyprogramme transmission does not exceed the limits allowed by Administrations, it is recommended that broadcasting organizations and the terminal ISPCs of the international sound\(hyprogramme connection should use volume\(hymeters or peak programme meters, the same type of meter being used for preference by both the telephone Administration and the broadcasting organization of a country. .PP Since the international sound\(hyprogramme connection is accurately adjusted before it is made available to the broadcasting organizations, there will be no danger of overloading the amplifiers during the sound\(hyprogramme transmission if care is taken not to exceed the permissible limit at the sending end of the international sound\(hyprogramme connection. .PP Hence, this check can be done only by the broadcasting organization and the ISPC of the transmitting country, and a check made further down the line would not seem to be very effective. .PP If so desired, monitoring equipment (volume\(hymeters, peak\(hyindicators) can be connected at the receiving end of the international sound\(hyprogramme link and of the international sound\(hyprogramme connection to obtain information about the general nature of the transmission. In this case, monitoring equipment at the two locations in the incoming country will have to be of the same type, but there is no need for the same kind of monitoring equipment to be used in both outgoing country and incoming country. .RT .sp 2P .LP \fB1\fR \fBMaximum level permitted on sound\(hyprogramme circuits\fR .sp 1P .RT .PP The peak power permitted on a sound\(hyprogramme circuit should not exceed +9\ dBm at a point of zero relative level on the sound\(hyprogramme circuit. .PP (This corresponds to a peak voltage of 3.1\ volts when measured as a 600\(hyohm through\(hylevel at a zero through relative level point. The r.m.s. value of the sinusoidal signal with this peak value is 2.2\ volts). .PP If a transmission system overload is identified as being due to sound\(hyprogramme transmission on 6.4\ kHz or 10\ kHz sound\(hyprogramme circuits, the level at the zero relative point should be reduced by 3\ dB to achieve an accompanying reduction in peak power, in accordance with Recommendation\ J.22, \(sc\ A.2\ [1]. .bp .RT .sp 2P .LP \fB2\fR \fBMaximum level permitted on an international telephone circuit used to carry a sound\(hyprogramme transmission\fR .sp 1P .RT .PP The power permitted on the international telephone circuit carrying a sound\(hyprogramme transmission should not exceed +3\ dBm at a point of zero relative level on the international telephone circuit. To allow the +9\ dBm0 peak level permitted on a sound\(hyprogramme circuit a 6\ dB loss should be introduced at a point before the international telephone circuit enters a carrier system. At the receiving side a corresponding amplification of 6\ dB at the end of the telephone circuit should be provided. .PP This reduction is necessary to avoid overloading on the carrier's system. Reasons for the possible overload are: .RT .LP a) Commentary circuits are used in one direction only in comparison to a normal telephone connection. This leads to an increase of the mean power level. .LP b) In most cases the broadcasting authorities use better quality microphones compared with normal telephone sets. .PP Experience has shown that an attenuation of 6\ dB is the most suitable value for this purpose. .sp 2P .LP \fBReference\fR .sp 1P .RT .LP [1] CCITT Recommendation \fIPerformance characteristics of 10\ kHz type\fR \fIsound\(hyprogramme circuits\fR , Red Book, Vol.\ III, Rec.\ J.22, ITU, Geneva,\ 1984. \v'6p' .sp 2P .LP \fBRecommendation\ N.16\fR .RT .sp 2P .sp 1P .ce 1000 \fBIDENTIFICATION\ SIGNAL\fR .EF '% Fascicle\ IV.3\ \(em\ Rec.\ N.16'' .OF '''Fascicle\ IV.3\ \(em\ Rec.\ N.16 %' .ce 0 .sp 1P .PP At times during the preparatory period when no test transmission is taking place and during pauses when no programme transmission is taking place it is very desirable for broadcasting organizations to arrange that their studios and transmitting stations send \fIidentification signals\fR over the international sound\(hyprogramme connection and over the control circuits whilst they are not in use to indicate that the circuits are connected. During the preparatory period, particularly, the identification signal will serve to show for which sound\(hyprogramme transmission the circuit is to be used. .sp 1P .RT .PP This identification signal will not be broadcast, so that it will not be heard by listeners, but will be transmitted from end to end of the international sound\(hyprogramme connection, from the programme origin to the destination. .PP The level of the identification signal applied to a sound\(hyprogramme connection should not exceed a mean absolute power level of \(em15\ dBm0. \v'6p' .RT .sp 2P .LP \fBRecommendation\ N.17\fR .RT .sp 2P .sp 1P .ce 1000 \fBMONITORING\ THE\ TRANSMISSION\fR .EF '% Fascicle\ IV.3\ \(em\ Rec.\ N.17'' .OF '''Fascicle\ IV.3\ \(em\ Rec.\ N.17 %' .ce 0 .sp 1P .PP The transmission may be monitored in the terminal ISPCs by means of loudspeakers and/or apparatus with a visual display (peak programme meters, vu\(hymeters, oscilloscopes, etc.). The means for monitoring the transmission should allow both visible and audible indications. .sp 1P .RT .PP Digital sound\(hyprogramme circuits established on 2048\ kbit/s systems include a sound\(hyprogramme signalling channel , allowing the exchange of service information, for example: .LP \(em transmission timing, .LP \(em identification signal, .LP \(em type of sound\(hyprogramme circuit carried. .PP These will be decoded by appropriate devices to determine the elements for charging as required in Recommendation\ N.18. .bp .sp 2P .LP \fBRecommendation\ N.18\fR .RT .sp 2P .sp 1P .ce 1000 \fBMONITORING\ FOR\ CHARGING\ PURPOSES,\ RELEASING\fR .EF '% Fascicle\ IV.3\ \(em\ Rec.\ N.18'' .OF '''Fascicle\ IV.3\ \(em\ Rec.\ N.18 %' .ce 0 .sp 1P .PP The monitoring of an international sound\(hyprogramme transmission for charging purposes is carried out at the terminal ISPC of the international sound\(hyprogramme link. .sp 1P .RT .PP The technical staff of the designated ISPCs should come to an arrangement among themselves so that at the end of the sound\(hyprogramme transmission they have accurate knowledge of: .LP a) the time of handing over the sound\(hyprogramme link to the broadcasting organization (beginning of chargeable duration); .LP b) the time at which the sound\(hyprogramme link is released by the broadcasting organization (end of chargeable duration); .LP c) where appropriate, the times and duration of every interruption or incident which may have occurred (in order to allow the operating services to determine whether a rebate is due, and if so, its amount). .PP The times of the beginning and of the end of the chargeable duration, as well as the times of occurrence and duration of any breakdowns which may occur, are entered on a daily report. This daily report is sent on the same day to the service responsible for coordinating all the details necessary for the establishment of the international accounts. .PP The conditions governing charging for sound\(hyprogramme circuits and control circuits are given in Recommendation\ D.180\ [1]. .RT .sp 2P .LP \fBReference\fR .sp 1P .RT .LP [1] CCITT Recommendation \fIOccasional provision of circuits for\fR \fIInternational sound\(hy and television\(hyprogramme transmissions\fR , Vol.\ II, \fR Rec.\ D.180. \v'1P' .IP \fB1.3\ Lining\(hyup and maintenance of international sound\(hyprogramme circuits\fR .sp 1P .RT .sp 2P .LP \fBRecommendation\ N.21\fR .RT .sp 2P .ce 1000 \fBLIMITS\ AND\ PROCEDURES\ FOR\ THE\ LINING\(hyUP\fR .EF '% Fascicle\ IV.3\ \(em\ Rec.\ N.21'' .OF '''Fascicle\ IV.3\ \(em\ Rec.\ N.21 %' .ce 0 .sp 1P .ce 1000 \fBOF\ A\ SOUND\(hyPROGRAMME\ CIRCUIT\fR .ce 0 .sp 1P .LP \fB1\fR \fBGeneral\fR .sp 1P .RT .PP This Recommendation gives limits in Tables 1/N.21 to 5/N.21 for the lining\(hyup of an international sound\(hyprogramme circuit as defined in Recommendation\ N.1. These limits correspond to those for one audio section of the hypothetical reference circuit as defined in CCIR Recommendation\ 502\ [1] for 5\ kHz, 6.4\ kHz, 7\ kHz and 10\ kHz sound\(hyprogramme circuits, but correspond to two audio sections .FS The limits derived for one audio to audio section .PP for sound\(hyprogramme circuits of 15\ kHz nominal bandwidth calculated in accordance with CCIR Recommendation\ 605\ [2] are not met by the technical specification of available equipment in use on the international network. .FE for 15\ kHz type sound\(hyprogramme circuits except for noise limits which correspond to one audio section. .PP It is recommended to use an automatic measuring equipment (see Recommendations\ O.31\ [3], O.32\ [4] and\ O.33\ [5]). If no such equipment is available, measurements shall normally be restricted to loss/frequency distortion and weighted noise. For stereophonic pairs , the parameters Nos. 12, 13, 14 and 15 of Table\ 1/N.21 shall also be measured. .PP The limits for 15\ kHz and 7\ kHz circuits are applicable both for analogue and digital transmissions. .bp .RT .sp 2P .LP \fB2\fR \fBLimits for the loss/frequency distortion of the component parts of an international sound\(hyprogramme circuit\fR .sp 1P .RT .PP The limits are expressed in terms of the received level relative to the value of the received level at 1020\ Hz. .FS For further information about the choice of test signal frequency, refer to Recommendation\ O.6\ [7]. .FE [6]. Some remarks with regard to the impedance at the points of interconnection are given in the introduction to Recommendation\ N.10. .PP International sound\(hyprogramme circuits set up between ISPCs in any particular continent should usually be routed on a single group link (which includes only one circuit section, that is, one equipment for modulation from audio\(hyfrequencies and one for demodulation to audio\(hyfrequencies). Long international sound\(hyprogramme circuits between ISPCs in different continents should not comprise more than three circuit sections. .PP Sound\(hyprogramme circuits such as those associated with television transmissions using communication satellite systems are normally provided on a temporary basis. The international sound\(hyprogramme circuit section is established via the satellite link(s) each time it is required for service. It should be noted that the group carrying the sound\(hyprogramme circuit may terminate either at the earth station or at an international terminal repeater station. .PP The possible combination of group\(hyterminals and the number of group\(hysections required for sound\(hyprogramme circuits established by satellite link(s) are such that it may not be possible to meet the group\(hylink limits without group\(hylink equalization for each sound\(hyprogramme circuit set up. .PP To avoid this situation, it may become necessary to tighten the limits for the loss at all frequencies and for the loss at the approximate mid\(hyband frequency of the national and satellite group\(hysections. .RT .sp 2P .LP \fB3\fR \fBLining\(hyup procedures\fR .sp 1P .RT .PP When each national section of the international sound\(hyprogramme circuit and each section crossing a frontier has been equalized for loss/frequency distortion and, where necessary, for phase/frequency distortion, so as to meet CCITT Recommendations, these various sections are interconnected to form the complete international sound\(hyprogramme circuit. .PP When agreement has been reached between two countries, operating via a communication satellite, to provide sound\(hyprogramme circuits on a temporary basis, it is necessary to carry out an initial line\(hyup of the sound\(hyprogramme circuit using the same satellite and terrestrial facilities as will be used each time a sound\(hyprogramme transmission is required. .PP In the case of international multiple destination sound\(hyprogramme circuits, the number and location of all destinations is known only at the time of a transmission booking. The lining\(hyup can therefore be carried out only after the booking details are known and must be carried out prior to the transmission. .PP \fR The individual basic groups will have been set up and lined up for single destination sound\(hyprogramme circuit requirements. When these are formed into a multiple\(hydestination group, only pilot levels need be checked. The send reference station for the multiple destination group will coordinate this work in accordance with Recommendation\ M.460\ [8]. .RT .sp 1P .LP 3.1 \fIMeasurement of received level\fR | 6] .sp 9p .RT .PP A test signal of 1020\ Hz is applied to the sending end of the international sound\(hyprogramme circuit at a level equivalent to \(em12\ dBm0. The level is measured at the receiving end of the circuit (output of last amplifier) and is adjusted to the nominal value appropriate to the ISPC (for example, \(em6\ dBm). .bp .PP An automatic measuring equipment [3], [4], [5], may then be used to trace the curve of received level with frequency at the receiving end of the circuit. If no such equipment is available, individual measurements must be made at the terminal ISPC and at the frontier section at the following frequencies: .RT .LP \(em for a 10\(hykHz circuit: 50, 80, 100, 200, 500, 800, 1000, 2000, 3200, 5000, 6000, 8500, 10 | 00\ Hz; and if considered useful: 30, 40, 11 | 00, 12 | 00 and 15 | 00\ Hz: .LP \(em for a 6.4\(hykHz circuit: 50, 80, 100, 200, 500, 800, 1000, 2000, 3200, 5000 and 6400\ Hz. .FS Administrations are invited to propose measuring frequencies for 5\ kHz circuits, 7\ kHz circuits, and 15\ kHz circuits. ISO standard No.\ 266\ [9] should be taken into account. .FE .PP The equalizers are adjusted to bring the curve within CCITT limits, which are given above. .sp 1P .LP 3.2 \fIMeasurement of group\(hydelay distortion\fR | 6] .sp 9p .RT .PP If necessary, the group\(hydelay distortion/frequency characteristic is plotted for the whole international sound\(hyprogramme circuit. .RT .sp 1P .LP 3.3 \fIMeasurement of circuit noise\fR .sp 9p .RT .PP When, after all necessary adjustments, the international sound\(hyprogramme circuit meets the CCITT Recommendations, noise measurements are made. .PP These should consist of the weighted noise reading using a meter and network conforming to Recommendation\ O.41\ [10] or CCIR Recommendation\ 468\ [11] or a combination of these. .PP The noise limits given in the tables of this Recommendation are for circuits of 840\ km maximum length. For longer circuits appropriate limits may be calculated from the formula given in CCIR Recommendation\ 605\ [2]. .RT .sp 1P .LP 3.4 \fIMeasurement of nonlinearity distortion\fR .sp 9p .RT .PP For circuits routed entirely on audio pairs and not equipped with pre\(hyemphasis equipment the nonlinearity distortion is measured at the end of the international sound\(hyprogramme circuit by sending, for a few seconds, a sinusoidal signal at an appropriate frequency in the band to be transmitted at a level of +9\ dBm0. .PP For a circuit which includes at least one carrier section no measurement of nonlinearity distortion should be made. However, if, in very exceptional cases, it should be essential, in order to provide service on such a circuit, to carry out a check of nonlinearity distortion, for example, to locate a fault, the frequency of the sent signal should not exceed 1020\ Hz at +9\ dBm0 and the period for which the tone is connected should be as short as possible \(em\ that is, not more than about four seconds. However the best procedure would be to use a suitable automatic measuring equipment if such is available (see Recommendation\ O.31\ [3], [4],\ [5]). .PP The total harmonic\(hydistortion coefficient for the sound\(hyprogramme hypothetical reference\(hycircuit (2500\ km) must not exceed 4% (harmonic margin 28\ dB) at any frequency .FS The European Broadcasting Union has stated that many of its members have expressed the opinion that for a circuit 1500\ km long, acceptable limits for nonlinearity distortion would be: 40\ dB at fundamental frequencies above 100\ Hz, 34\ dB at fundamental frequencies of 100\ Hz and below. .FE within the transmitted band. For shorter and for less complex circuits, the distortion should be less. .PP Moreover, since end\(hyto\(hyend measurements of nonlinearity distortion on circuits routed on carrier systems might give rise to serious disturbance to transmission on other channels, especially if the group is transmitted on a transistorized carrier system, it is permitted to make only local measurements of non\(hylinearity distortion on terminal modulating and demodulating equipments. For example, a sound\(hyprogramme circuit modulating and demodulating equipment could be connected back\(hyto\(hyback via a suitable network (and suitable amplifiers if necessary) and the measurement made on the resulting complete assembly. .RT .sp 1P .LP 3.5 \fIAdditional mesurements\fR .sp 9p .RT .PP In addition to the measurements specified above, the following parameters may be measured at the discretion of the Administrations concerned. Such measurements may be particularly useful when a faulty condition is suspected. .bp .RT .sp 1P .LP 3.5.1 \fIInterference caused by power supply sources\fR .sp 9p .RT .PP When a sinusoidal test signal is transmitted over a sound\(hyprogramme circuit at a level of 0\ dBmO the level of the strongest unwanted modulation component should not exceed \(em45\ dBmO. .RT .sp 1P .LP 3.5.2 \fIFrequency error\fR .sp 9p .RT .PP The frequency error introduced by a sound programme circuit must not exceed the following limits: .RT .LP 7 kHz, 115 kHz \(+- | Hz .LP 5 kHz, 6.4 kHz, 10 kHz \(+- | Hz .sp 1P .LP 3.6 \fIApplication of a simulated sound\(hyprogramme test signal\fR .sp 9p .RT .PP CCIR Recommendation 571 [12] specifies a simulated sound\(hyprogramme test equipment which can be used for measuring interference in other channels. .RT .sp 1P .LP 3.7 \fISingle tone\(hyinterference level\fR .sp 9p .RT .PP Where this parameter is concerned, the characteristic of the weighting filter according to CCIR Recommendation\ 468\ [11] has to be taken into account by using the correction factor \(*q. The latter, which can be determined from Figure\ 1/N.21 (identical with Figure\ 1b of CCIR Recommendation\ 468\ [11] is to be subtracted from the numerical values of the tables. To exclude the effect of random noise, selective measurement is needed. .RT .LP .rs .sp 23P .ad r \fBFigure 1/N.21, p. 2\fR .sp 1P .RT .ad b .RT .sp 1P .LP 3.8 \fIMeasurement of stereophonic pairs\fR .sp 9p .RT .PP The quality criteria given refer to those of Recommendations\ O.32\ [4] and\ O.33\ [5]. The limits can be easily measured with the aid of such equipments. If other measuring means are used, attention is drawn to the fact that the frequencies of 10, 11.92 and 14\ kHz should be avoided because of possible stop filters which may be inserted in the transmission equipment concerned for reducing carrier leaks. .bp .RT .sp 1P .LP 3.9 \fIRecord of results\fR .sp 9p .RT .PP The final measurements made under the above headings when the circuit has been lined up are reference measurements and should be carefully recorded. .RT .ce \fBH.T. [1T1.21]\fR .ce TABLE\ 1/N.21 .ce \fBLimits for the lining\(hyup of 15 kHz sound\(hyprogramme circuits\fR .ps 9 .vs 11 .nr VS 11 .nr PS 9 .TS center box; cw(24p) | cw(126p) | cw(30p) | cw(30p) . Item Parameter Unit Limits _ .T& lw(24p) | lw(66p) | lw(60p) | lw(30p) | lw(30p) , ^ | ^ | l | l | l. .T& lw(24p) | lw(66p) | lw(60p) | lw(30p) | lw(30p) , ^ | ^ | l | l | l. .T& rw(24p) | cw(66p) | lw(60p) | lw(30p) | lw(30p) , ^ | ^ | l | l | l. { TABLE\ 1/N.21\ \fI(cont.)\fR } .T& cw(24p) | cw(126p) | cw(30p) | cw(30p) . Item Parameter Unit Limits _ .T& lw(24p) | lw(126p) | lw(30p) | lw(30p) . .T& lw(18p) | lw(24p) | lw(66p) | lw(60p) | lw(30p) | lw(30p) , ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l. .T& lw(18p) | lw(24p) | lw(66p) | lw(60p) | lw(30p) | lw(30p) , ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l. { 12 Difference in gain between A and B channels 0.04 to 0.125 kHz dB \ 1.1 0.125 to 10 kHz dB \ 0.6 10 to 14 kHz dB \ 1.1 14 to 15 kHz dB \ 2.3 } .T& lw(18p) | lw(24p) | lw(66p) | lw(60p) | lw(30p) | lw(30p) , ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l. { 13 Phase difference between A and B channels 0.04 to 0.2 kHz degree \ 23 0.2 to 4 kHz degree \ 11 14 kHz degree \ 23 15 kHz degree \ 30 } .T& lw(18p) | lw(24p) | lw(126p) | lw(30p) | lw(30p) . { 14 Intelligible crosstalk ratio A/B dB \ 52 } .T& lw(18p) | lw(24p) | lw(126p) | lw(30p) | lw(30p) . { 15 Crosstalk ratio (intermodulation) A/B dB \ 62 \fBMONTAGE:\fR Additional parameters for stereo transmission } .TE .nr PS 9 .RT .ad r \fBTableau 1/N.21 [1T1.21], p. 3\fR .sp 1P .RT .ad b .RT .LP .rs .sp 3P .ad r Blanc .ad b .RT .LP .bp .ce \fBH.T. [2T1.21]\fR .ce TABLE\ 1/N.21\ \fI(cont.)\fR .ps 9 .vs 11 .nr VS 11 .nr PS 9 .TS center box; cw(24p) | cw(126p) | cw(30p) | cw(30p) . Item Parameter Unit Limits _ .T& lw(24p) | lw(126p) | lw(30p) | lw(30p) . .T& lw(18p) | lw(24p) | lw(66p) | lw(60p) | lw(30p) | lw(30p) , ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l. .T& lw(18p) | lw(24p) | lw(66p) | lw(60p) | lw(30p) | lw(30p) , ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l. { 12 Difference in gain between A and B channels 0.04 to 0.125 kHz dB \ 1.1 0.125 to 10 kHz dB \ 0.6 10 to 14 kHz dB \ 1.1 14 to 15 kHz dB \ 2.3 } .T& lw(18p) | lw(24p) | lw(66p) | lw(60p) | lw(30p) | lw(30p) , ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l. { 13 Phase difference between A and B channels 0.04 to 0.2 kHz degree \ 23 0.2 to 4 kHz degree \ 11 14 kHz degree \ 23 15 kHz degree \ 30 } .T& lw(18p) | lw(24p) | lw(126p) | lw(30p) | lw(30p) . { 14 Intelligible crosstalk ratio A/B dB \ 52 } .T& lw(18p) | lw(24p) | lw(126p) | lw(30p) | lw(30p) . { 15 Crosstalk ratio (intermodulation) A/B dB \ 62 \fBMONTAGE:\fR Additional parameters for stereo transmission } .TE .nr PS 9 .RT .ad r \fBTableau 1/N.21 [2T1.21], p. 4\fR .sp 1P .RT .ad b .RT .LP .bp .ce \fBH.T. [T2.21]\fR .ce TABLE\ 2/N.21 .ce \fBLimits for the lining\(hyup of 10 kHz international\fR .ce \fBsound\(hyprogramme circuits\fR .ps 9 .vs 11 .nr VS 11 .nr PS 9 .TS center box; cw(24p) | cw(144p) | cw(30p) | cw(30p) . Item Parameter Unit Limits _ .T& lw(24p) | lw(72p) | lw(72p) | lw(30p) | lw(30p) , ^ | ^ | l | l | l. .T& lw(24p) | lw(144p) | lw(30p) | lw(30p) . .TE .nr PS 9 .RT .ad r \fBTableau 2/N.21 [T2.21], p. 5\fR .sp 1P .RT .ad b .RT .LP .bp .ce \fBH.T. [T3.21]\fR .ce TABLE\ 3/N.21 .ce \fBLimits for the lining\(hyup of 7 kHz international\fR .ce \fBsound\(hyprogramme circuits\fR .ps 9 .vs 11 .nr VS 11 .nr PS 9 .TS center box; cw(24p) | cw(144p) | cw(30p) | cw(30p) . Item Parameter Unit Limits _ .T& lw(24p) | lw(72p) | lw(72p) | lw(30p) | lw(30p) , ^ | ^ | l | l | l. .T& lw(24p) | lw(144p) | lw(30p) | lw(30p) . .TE .nr PS 9 .RT .ad r \fBTableau 3/N.21 [T3.21], p. 6\fR .sp 1P .RT .ad b .RT .LP .bp .ce \fBH.T. [T4.21]\fR .ce TABLE\ 4/N.21 .ce \fBLimits for the lining\(hyup of 6.4 kHz international\fR .ce \fBsound\(hyprogramme circuits\fR .ps 9 .vs 11 .nr VS 11 .nr PS 9 .TS center box; cw(24p) | cw(144p) | cw(30p) | cw(30p) . Item Parameter Unit Limits _ .T& lw(24p) | lw(72p) | lw(72p) | lw(30p) | lw(30p) , ^ | ^ | l | l | l. .T& lw(24p) | lw(144p) | lw(30p) | lw(30p) . .TE .nr PS 9 .RT .ad r \fBTableau 4/N.21 [T4.21], p. 7\fR .sp 1P .RT .ad b .RT .LP .bp .ce \fBH.T. [T5.21]\fR .ce TABLE\ 5/N.21 .ce \fBLimits for the lining\(hyup of 5 kHz international\fR .ce \fBsound\(hyprogramme circuits\fR .ps 9 .vs 11 .nr VS 11 .nr PS 9 .TS center box; cw(24p) | cw(144p) | cw(30p) | cw(30p) . Item Parameter Unit Limits _ .T& lw(24p) | lw(72p) | lw(72p) | lw(30p) | lw(30p) , ^ | ^ | l | l | l. .T& lw(24p) | lw(144p) | lw(30p) | lw(30p) . .TE .nr PS 9 .RT .ad r \fBTableau 5/N.21 [T5.21], p. 8\fR .sp 1P .RT .ad b .RT .LP .bp .sp 2P .LP \fBReferences\fR .sp 1P .RT .LP [1] CCIR Recommendation \fIHypothetical reference circuits for\fR \fIsound\(hyprogramme transmissions\fR , Vol.\ XII, Rec.\ 502, ITU, Geneva, 1986. .LP [2] CCIR Recommendation \fIEstimation of transmission performance of\fR \fIsound\(hyprogramme circuits shorter or longer than the hypothetical reference\fR \fIcircuit\fR , Vol.\ XII, Rec.\ 605, ITU, Geneva,\ 1986. .LP [3] CCITT Recommendation \fIAutomatic measuring equipment for\fR \fIsound\(hyprogramme circuits\fR , Vol.\ IV, Rec.\ O.31. .LP \fR [4] CCITT Recommendation \fIAutomatic measuring equipment for stereophonic\fR \fIpairs of sound\(hyprogramme circuits\fR , Vol.\ IV, Rec.\ O.32. .LP [5] CCITT Recommendation \fIAutomatic equipment for rapidly measuring\fR \fIstereophonic pairs and monophonic sound\(hyprogramme circuits, links and\fR \fIconnections,\fR Vol.\ IV, Rec.\ O.33. .LP [6] CCIR Report \fIRelative values of sound\(hyprogramme signal levels\fR \fIestablished with the VU meter and with a peak\(hyprogramme meter\fR , Vol.\ XII, Rep.\ 820, Geneva,\ 1986. .LP [7] CCITT Recommendation \fI1020 Hz reference test frequency,\fR Vol.\ IV, Rec.\ O.6. .LP [8] CCITT Recommendation \fIBringing international group, supergroup, etc.,\fR \fIlinks into service\fR , Vol.\ IV, Rec.\ M.460. .LP [9] ISO Standard No. 266 \fIAcoustics\(hypreferred frequencies for\fR \fImeasurements\fR . .LP [10] CCITT Recommendation \fIPsophometers (apparatuses for the objective\fR \fImeasurements of circuit noise)\fR , Vol.\ IV, Rec.\ O.41. .LP [11] CCIR Recommendation \fIMeasurement of audio\(hyfrequency noise voltage\fR \fIlevel in sound broadcasting\fR , Vol.\ X, Rec.\ 468, ITU, Geneva,\ 1986. .LP [12] CCIR Recommendation \fIA conventional test signal simulating\fR \fIsound\(hyprogramme signals for measuring interference in other channels\fR , Vol.\ XII, Rec.\ 571, ITU, Geneva,\ 1986. .LP [13] CCIR Recommendation \fIPerformance characteristics of 10 kHz type\fR \fIsound\(hyprogramme circuits\fR , Vol.\ XII, Rec.\ 504, ITU, Geneva,\ 1982. \v'6p' .sp 2P .LP \fBRecommendation\ N.23\fR .RT .sp 2P .ce 1000 \fBMAINTENANCE\ MEASUREMENTS\ TO\ BE\ MADE\fR .EF '% Fascicle\ IV.3\ \(em\ Rec.\ N.23'' .OF '''Fascicle\ IV.3\ \(em\ Rec.\ N.23 %' .ce 0 .sp 1P .ce 1000 \fBON\ INTERNATIONAL\ SOUND\(hyPROGRAMME\ CIRCUITS\fR .ce 0 .sp 1P .LP \fB1\fR \fBGeneral\fR .sp 1P .RT .PP In Tables 1/N.23 to 5/N.23 maintenance limits for international sound\(hyprogramme circuits are specified. If these limits are exceeded, the control station .FS For the functions and responsibilities of the circuit control stations see Recommendation N.5. .FE for the circuit should decide the appropriate action to be taken to bring the circuit back within these limits. .RT .sp 2P .LP \fB2\fR \fBRoutine measurements\fR .sp 1P .RT .PP Routine measurements should be made every six months and the circuit realigned to meet the limits given in Recommendation\ N.21. The control station should agree with other stations, the date and time of routine measurements and the parameters to be included. It is recommended to use an automatic measuring equipment (see Recommendations\ O.31\ [1], O.32\ [2], O.33\ [3]). The test procedures and frequencies to be used are detailed in Recommendation\ N.21. If no automatic measuring equipment is available, measurements shall normally be restricted to loss/frequency distortion and weighted noise. For the stereophonic pairs , the parameters Nos. 12, 13, 14 and 15 of Table\ 1/N.23 shall also be measured. .RT .sp 2P .LP \fB3\fR \fBRelease of circuit for routine measurements\fR .sp 1P .RT .PP Even if there is a general understanding with a renter of a permanently leased circuit on the time when routine tests are to be carried out, the ISPC should always confirm with the renter that the circuit can be released for these tests. .bp .RT .ce \fBH.T. [1T1.23]\fR .ce TABLE\ 1/N.23 .ce \fBLimits for international\fR .ce \fB15 kHz sound\(hyprogramme circuits\fR .ps 9 .vs 11 .nr VS 11 .nr PS 9 .TS center box; cw(24p) | cw(126p) | cw(30p) | cw(30p) . Item Parameter Unit Limits _ .T& lw(24p) | lw(66p) | lw(60p) | lw(30p) | lw(30p) , ^ | ^ | l | l | l. .T& lw(24p) | lw(126p) | lw(30p) | lw(30p) . .T& rw(24p) | cw(126p) | lw(30p) | lw(30p) . { TABLE\ 1/N.23\ \fI(cont.)\fR } .T& cw(24p) | cw(126p) | cw(30p) | cw(30p) . Item Parameter Unit Limits .T& lw(18p) | lw(24p) | lw(66p) | lw(60p) | lw(30p) | lw(30p) , ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l. { 12 Difference in gain between A and B channels 0.04 to 0.125 kHz dB \ 1.5 0.125 to 10 kHz dB \ 0.8 10 to 14 kHz dB \ 1.5 14 to 15 kHz dB \ 3 } .T& lw(18p) | lw(24p) | lw(66p) | lw(60p) | lw(30p) | lw(30p) , ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l. { 13 Phase difference between A and B channels 0.04 to 0.125 kHz degree \ 30 0.02 to 4 kHz degree \ 15 14 kHz degree \ 30 15 kHz degree \ 40 } .T& lw(18p) | lw(24p) | lw(126p) | lw(30p) | lw(30p) . { 14 Intelligible crosstalk ratio A/B dB \ 50 } .T& lw(18p) | lw(24p) | lw(126p) | lw(30p) | lw(30p) . { 15 Crosstalk ratio (intermodulation) A/B dB \ 60 } .TE .LP \fINote\fR \ \(em\ The limits given in this table are applicable both for analogue and digital transmissions. .LP \fBMONTAGE:\fR Additional parameters for stereo transmission .ad r \fBTableau 1/N.23 [1T1.23], p. 9\fR .sp 1P .RT .ad b .RT .LP .bp .ce \fBH.T. [2T1.23]\fR .ce TABLE\ 1/N.23\ \fI(cont.)\fR .ps 9 .vs 11 .nr VS 11 .nr PS 9 .TS center box; cw(24p) | cw(126p) | cw(30p) | cw(30p) . Item Parameter Unit Limits .T& lw(18p) | lw(24p) | lw(66p) | lw(60p) | lw(30p) | lw(30p) , ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l. { 12 Difference in gain between A and B channels 0.04 to 0.125 kHz dB \ 1.5 0.125 to 10 kHz dB \ 0.8 10 to 14 kHz dB \ 1.5 14 to 15 kHz dB \ 3 } .T& lw(18p) | lw(24p) | lw(66p) | lw(60p) | lw(30p) | lw(30p) , ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l ^ | ^ | ^ | l | l | l. { 13 Phase difference between A and B channels 0.04 to 0.125 kHz degree \ 30 0.02 to 4 kHz degree \ 15 14 kHz degree \ 30 15 kHz degree \ 40 } .T& lw(18p) | lw(24p) | lw(126p) | lw(30p) | lw(30p) . { 14 Intelligible crosstalk ratio A/B dB \ 50 } .T& lw(18p) | lw(24p) | lw(126p) | lw(30p) | lw(30p) . { 15 Crosstalk ratio (intermodulation) A/B dB \ 60 } .TE .LP \fINote\fR \ \(em\ The limits given in this table are applicable both for analogue and digital transmissions. .LP \fBMONTAGE:\fR Additional parameters for stereo transmission .RT .ad r \fBTableau 1/N.23 [2T1.23], p. 10\fR .sp 1P .RT .ad b .RT .LP .bp .ce \fBH.T. [T2.23]\fR .ce TABLE\ 2/N.23 .ce \fBLimits for international\fR .ce \fB10 kHz sound\(hyprogramme circuits\fR .ps 9 .vs 11 .nr VS 11 .nr PS 9 .TS center box; cw(24p) | cw(144p) | cw(30p) | cw(30p) . Item Parameter Unit Limits _ .T& lw(24p) | lw(72p) | lw(72p) | lw(30p) | lw(30p) , ^ | ^ | l | l | l. .T& lw(24p) | lw(144p) | lw(30p) | lw(30p) . .TE .nr PS 9 .RT .ad r \fBTableau 2/N.23 [T2.23], p. 11\fR .sp 1P .RT .ad b .RT .LP .bp .ce \fBH.T. [T3.23]\fR .ce TABLE\ 3/N.23 .ce \fBLimits for international\fR .ce \fB7 kHz sound\(hyprogramme circuits\fR .ps 9 .vs 11 .nr VS 11 .nr PS 9 .TS center box; cw(24p) | cw(144p) | cw(30p) | cw(30p) . Item Parameter Unit Limits _ .T& lw(24p) | lw(72p) | lw(72p) | lw(30p) | lw(30p) , ^ | ^ | l | l | l. .T& lw(24p) | lw(144p) | lw(30p) | lw(30p) . .TE .nr PS 9 .RT .ad r \fBTableau 3/N.23 [T3.23], p. 12\fR .sp 1P .RT .ad b .RT .LP .bp .ce \fBH.T. [T4.23]\fR .ce TABLE\ 4/N.23 .ce \fBLimits for international\fR .ce \fB6.4 kHz sound\(hyprogramme circuits\fR .ps 9 .vs 11 .nr VS 11 .nr PS 9 .TS center box; cw(24p) | cw(144p) | cw(30p) | cw(30p) . Item Parameter Unit Limits _ .T& lw(24p) | lw(72p) | lw(72p) | lw(30p) | lw(30p) , ^ | ^ | l | l | l. .T& lw(24p) | lw(144p) | lw(30p) | lw(30p) . .TE .nr PS 9 .RT .ad r \fBTableau 4/N.23 [T4.23], p. 13\fR .sp 1P .RT .ad b .RT .LP .bp .ce \fBH.T. [T5.23]\fR .ce TABLE\ 5/N.23 .ce \fBLimits for international\fR .ce \fB5 kHz sound\(hyprogramme circuits\fR .ps 9 .vs 11 .nr VS 11 .nr PS 9 .TS center box; cw(24p) | cw(144p) | cw(30p) | cw(30p) . Item Parameter Unit Limits _ .T& lw(24p) | lw(72p) | lw(72p) | lw(30p) | lw(30p) , ^ | ^ | l | l | l. .T& lw(24p) | lw(144p) | lw(30p) | lw(30p) . .TE .nr PS 9 .RT .ad r \fBTableau 5/N.23 [T5.23], p. 14\fR .sp 1P .RT .ad b .RT .sp 2P .LP \fBReferences\fR .sp 1P .RT .LP [1] CCITT Recommendation \fIAutomatic measuring equipment for sound\(hyprogramme\fR \fIcircuits\fR , Vol.\ IV, Rec.\ O.31. .LP [2 CCITT Recommendation \fIAutomatic measuring equipment for stereophonic\fR \fIpairs of sound\(hyprogramme circuits,\fR Vol.\ IV, Rec.\ O.32. .LP [3] CCITT Recommendation \fIAutomatic equipment for rapidly measuring\fR \fIstereophonic pairs and monophonic sound\(hyprogramme circuits, links and\fR \fIconnections,\fR Vol.\ IV, Rec.\ O.33. .LP [4] CCIR Recommendation \fIPerformance characteristics of 10 kHz type\fR \fIsound\(hyprogramme circuits\fR , Vol.\ XII, Recommendation\ 504, ITU, Geneva,\ 1982. .LP .bp