Speech coding activities within CCITT: Status and trends

During the last meeting of CCITT Study Group XVIII in GENEVA (June 1981), a number of telecommunications Administrations expressed their intention of defining new standards for the encoding of telephone signals. These new standards would require more sophisticated signal processing techniques than the present A or µ-law 64 kbit/s PCM. This paper presents the progress of these studies their trends (bit-rate, applications) ; emphasis will the put on the possible algorithms (ADPCM, ADM, Sub Band Coding ...) which can be proposed for the new standards, and on the specific constraints of telecommunication networks.