1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 * TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%,%6)3)/.G0G0!.$G0G03/5.$G0G042!.3-)33)/.490%3G0G0/ amended at Geneva, 1972 and 1980, and at Melbourne, 1988)The CCITT recognizes the types of sound-programme circuits defined below.Note For the purposes of
2、this Recommendation and other Recommendations in the Series J, sound-programme circuits have been classified in terms of the nominal effectively transmitted bandwith. For convenience, thecorresponding type of circuit from the administrative point of view (see Recommendation D.180 1) is given underea
3、ch type of equipment in the following paragraphs.1 15 kHz-type sound-programme circuitThis type of circuit is recommended for high-quality monophonic programme transmission and in certainarrangements is also recommended for stereophonic transmissions. This type of circuits corresponds to the “verywi
4、deband circuits” or “stereophonic pair”, as appropriate, referred to in Recommendation D.180 1.The performance characteristics of 15 kHz-type sound-programme circuits suitable for both monophonic andstereophonic transmissions are defined in Recommendation J.21 and suitable equipment is specified inR
5、ecommendation J.31, for analogue transmission and in Recommendations J.41, G.735 and G.737 for digitaltransmission.2 10 kHz-type sound-programme circuitThis type of circuit, previously known as the “normal programme circuit, type A”, is recommended formonophonic transmission only. This type of circu
6、it corresponds to the “wideband circuit” referred to inRecommendation D.180 1. The performance characteristics or 10 kHz-type sound-programme circuits are defined inRecommendation J.22 and suitable methods of provision are given in Recommendation J.32.Note Recommendations J.22 and J.32 are reproduce
7、d in Fascicle III.4 or the Red Book, ITU, Geneva, 1985.3 Narrow bandwith 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 commentariesand reports on e
8、vents of large interest (e.g sporting events); and for permanent sound-programme circuits which are used primarily for speech transmission or as connectionbetween studio outputs and long-, medium- or short-wave broadcast-transmitter inputs.The performance characteristics of narrow bandwith sound-pro
9、gramme circuits are defined inRecommendation J.32, and as suitable equipment for 7 kHz-type circuit is specified in Recommendation J.34, foranalogue transmission.Note These types of circuits fall within the category of “medium-band circuits” referred to inRecommendation D.180 1 for tariff purposes.4
10、 Use or ordinary telephone circuitsFor this type of transmission of special programmes such as speech, some operational aspects are given inRecommendation N.15 2.References1 CCITT Recommendation Occasional provision of circuits for international sound- and television-programmetransmissions, Vol. II, Rec. D.180.2 CCITT Recommendation Maximum permissible power during an international sound-programmetransmission, Vol. IV, Rec. N.15.
