CEPT T L 03-02 E-1981 PCM Coding and Multiplexing for Telephony《电话技术PCM编码和多路复用》.pdf

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1、7 .- - - _ y CEPT T/L*03-02*E 81 2326434 0005993 I Ri Page 1 (old reference: T/TR 03-02 E) Recommendation T/L 03-02 (Innsbruck 1981) PCM CODING AM) MULTIPLEXING FOR TELEPHONY Recommendation proposed by Working Group T/GT 12 “Transmision UR) Text of the Recornmendation adopted by the “Telecommunicati

2、ons” Commission : “The European Conference of Postal and Telecommunications Administrations, considering - that PCM encoding of voice-frequency signals requires the use of very precise characteristics, - that it is important that performance characteristics should be met between the voice-frequency

3、ports of PCM coded channels, - that the installation and operation of primary PCM multiplex equipment from different origins require that they should be standardized, - that the relevant CCITT existing Recommendations contain various options and differences which are necessary on a worldwide basis,

4、- that the CEPT Administrations support the harmonization of telecommunication equipment and systems which could lead to a reduction in the development and production costs for the manufacturers supplying equipment to several countries, . o , recommends that the members of the CEPT adhere to the spe

5、cifications or PCM coding and multiplexing for telephony contained in this Recommendation,” Recommendation T/L 03-02 corresponds to the following CCITT Recommendations : Recommendation G.7 1 1 : “Pulse code modulation (PCM) of voice frequencies” with the following modifcation: “CEPT members only use

6、 the A-law.” Recommendation G.712; “Performance characteristics o PCM channels between 4-wire interfaces at voice frequen- cies” with the following modification: point 14: add after 5: concerning the levels at the voice-frequency ports, only solution 1 applies (+4 dBr, - 14 dBr). Recommendation G.71

7、3 : “Performance characteristics of PCM channels between 2-wire interfaces at voice frequen- Recommendation G.7 14 : “Separate performance characteristics for the send and receive sides of PCM channels applicable to 4-wire voice-frequency interfaces.” Recommendation G.732: “Characteristics of primary PCM multiplex equipment operating at 2,048 kbitls.” j ri O cies.” Edition of December 15, 1987 r-1 . I I