1、CCITT FASCICLE 111.6 89 = 4862591 0504233 4 3 Narrow bandwidth sound-programme circuit (7 and 5 kHz-type sound-programme circuit) These types of circuits are recommended: - for setting up a large number of temporary sound-programme circuits for the transmission of commentaries and reports on events
2、of large interest (e.g. sporting events): and for permanent sound-programme circuits which are used primarily for speech transmission or as connection between studio outputs and long-, medium- or short-wave broadcast-transmitter inputs. The performance characteristics of narrow bandwidth sound-progr
3、amme circuits are defined in Recom- mendation 5.23, and as suitable equipment for 7 kHz-type circuit is specified in Recommendation 5.34, for analogue transmission. Recommendation D.180 i for tariff purposes. - Note - These types of circuits fall within the category of “medium-band circuits” referre
4、d to in 4 Use of ordinary telephone circuits For this type of transmission of special programmes such as speech, some operational aspects are given in Recommendation N.15 2. References CCITT Recommendation Occasional provision of circuits for international sound- and television-programme transmissio
5、ns, Vol. II, Rec. D.180. CCITT Recommendation Maximum permissible power during an international sound-programme trans- mission, Vol. IV, Rec. N.15. 11 2 Recommendation 5.13 DEFINITIONS FOR INTERNATIONAL SOUND-PROGRAMME CIRCUITS (former Recommendation J.12; amended at Geneva, 1972 and 1980) Definitio
6、n of the constituent parts of an international sound-programme connection The following definitions apply to international sound-programme transmissions. 1 international sound-programme transmission The transmission of sound over the international telecommunication network for the purpose of inter-
7、changing sound-programme material between broadcasting organizations in different countries. Such a trans- mission includes all types of programme material normally transmitted by a sound broadcasting service, for example, speech, music, sound accompanying a television programme, etc. 2 broadcasting
8、 organization (send) The broadcasting organization at the sending end of the sound programme being transmitted over the international sound-programme connection. 3 broadcasting organization (receive) The broadcasting organization at the receiving end of the sound programme being transmitted over the
9、 international sound-programme connection. 4 international sound-programme centre (ISPC) A centre at which at least one international sound-programme circuit terminates and in which international sound-programme connections can be made by the interconnection of international and national sound- prog
10、ramme circuits. The ISPC is responsible for setting up and maintaining international sound-programme links and for the supervision of the transmissions made on them. 134 Fascicle 111.6 - Rec. 5.13 5 international sound-programme connection 5.1 The unidirectional path between the broadcasting organiz
11、ation (send) and the broadcasting organization (receive) comprising the international sound-programme link extended at its two ends over national sound- programme circuits to the broadcasting organizations (see Figure 21J.13). 5.2 The assembly of the “international sound-programme link” and the nati
12、onal circuits between the broadcasting organizations, constitutes the “international sound-programme connection”. Figure 3/J.13 illustrates, by way of example, an international sound-programme connection as it might be encountered in practice. 6 international sound-programme link (Figure 215.1 3) Th
13、e unidirectional path for sound-programme transmissions between the ISPCs of the two terminal countries involved in an international sound-programme transmission. The international sound-programme link comprises one or more international sound-programme circuits interconnected at intermediate ISPCs.
14、 It can also include national sound-programme circuits in transit countries. 7 international sound-programme circuit (Figure 1/5.13) The unidirectional transmission path between two ISPCs and comprising one or more sound-programme circuit sections (national or international), together with any neces
15、sary audio equipment (amplifiers, compan- dors, etc.). Country A 1 International round- programme circuit - National sound- progrsmme circuit section i i International sound-programme centre (iSPC) . I ! Country 6 National sound- -programme circuit 7 International section wund-progmmme centre (ISPC)
16、 k- International wund-programme circuit EIITr.37002 audio equipment audio equipment circuit section switching -J proper to X associated with FIGURE llJ.13 An international sound-programme circuit composed of two national and one international sound-programme circuit-section Country C I Broadcasting
17、 Country B I I 1 Country A Broadcasting r organization ISPC ISPC (rand) I I National Inierneiional Nations sound- I 1 sound- sound- Fprogrammeq programme 4 I_ programme k- International wund-prog Circuit P circuit ClrCuIt 1-International sound-programme connection circuits ! I audio equipment x asso
18、ciated with swiiching m-31102 FIGURE 2lJ.13 An international sound-programme link composed o international and national sound-programme circuits and extended on a national sound-programme circuit at each end to form an international sound-programmeconnection Fascicle 111.6 - Rec. 5.13 135 CCITT FASC
19、ICLE 111.6 89 I 4862591 0504235 8 9 Frankfurt ISPC +6dBrs London ISPC +6dBrs London BBC Praha ISPC +6dBrs Hamburg NSPC + 6dB rs Ham burg NDR O ispc A +iirs ispc ns pc O O - Ispc = local sound-programme circuit nspc = national sound-programme circuit is pc satspc = satellite sound-programme circuit N
20、SPC = switching centre for nspc and Ispc ISPC = switching centre for ispc, nspc and Ispc = internat io na1 sou nd-p rog ra m me circuit Raisting +6dBrs LT-;-j-j+ satspc ElTl - 33990 Earth station for satellite links “ore - Maximum level of wund programme signals: +YdBmOs (this means +9dBms at a OdBr
21、s relative level pint and + 15dBms at a +6dBrs relative levcl point respectively). The wlue of +9dBmscorresponds 10 a peak voltage of 3.1 V which is the maximum value of a sine-wave signal of 2.2 V r.m.s. I Other values can be chosen by the relevant Adniiiiistraiion on a national basis. FIGURE 31J.1
22、3 Diagram of an international snund-programme circuit 8 sound-programme circuit-section (Figure 1 /J. 13) Part of an international sound-programme circuit between two stations at which the programme is transmitted at audio frequencies. The normal method of providing a sound-programme circuit section
23、 in the international network will be by the use of carrier sound-programme equipment. Exceptionally sound-programme circuit sections will be provided by other means, for example, by using amplified unloaded or lightly loaded screened-pair cables or by using the phantoms of symmetric-pair carrier ca
24、bles. 9 national circuit The national circuit connects the ISPC to the broadcasting authority; this applies both at the sending and at the receiving end. A national circuit may also interconnect two ISPCs within the same country. 10 effectively transmitted signals in sound-programme transmission For
25、 sound-programme transmission, a signal at a particular frequency is said to be effectively transmitted if the nominal overall loss at that frequency does not exceed the nominal overall loss at 800 Hz by more than 4.3 dB. This should not be confused with the analogous definition concerning telephony
26、 circuits given in i. For sound-programme circuits, the overall loss (relative to that at 800 Hz) defining effectively transmitted frequency is 1.4 dB, Le. about one-third of the allowance. Reference CCIT Recommendation General performance objectives applicable to all modern international circuits and national extension circuits, Vol. III, Rec. G.151, Q 1, Note 1. 11 136 Fascicle 111.6 - Rec. 5.13
