- •FOREWORD
- •40, 32, 24, 16 kbit/s ADAPTIVE DIFFERENTIAL PULSE CODE MODULATION (ADPCM)1)
- •1 General
- •1.1 ADPCM encoder
- •1.2 ADPCM decoder
- •2 ADPCM encoder principles
- •2.1 Input PCM format conversion
- •2.2 Difference signal computation
- •2.3 Adaptive quantizer
- •2.4 Inverse adaptive quantizer
- •2.5 Quantizer scale factor adaptation
- •2.6 Adaptation speed control
- •2.7 Adaptive predictor and reconstructed signal calculator
- •2.8 Tone and transition detector
- •3 ADPCM decoder principles
- •3.1 Inverse adaptive quantizer
- •3.2 Quantizer scale factor adaptation
- •3.3 Adaptation speed control
- •3.4 Adaptive predictor and reconstructed signal calculator
- •3.5 Tone and transition detector
- •3.6 Output PCM format conversion
- •3.7 Synchronous coding adjustment
- •4 Computational details
- •4.1 Input and output signals
- •I.1 General transmission considerations
- •I.2 Interaction with other processes
- •I.3 Interaction with coding laws other than PCM
- •I.4 Encoder/decoder synchronization
- •I.5 Synchronous coding adjustment
- •I.6 Speech performance
- •I.7 Voice frequency telegraph performance
- •I.8 Data performance
- •I.9 Dual tone multi-frequency (DTMF) signalling
- •I.10 Facsimile
- •II.1 Purpose of digital test sequences
- •II.2 Diskette interface and format
INTERNATIONAL TELECOMMUNICATION UNION
CCITT |
G.726 |
THE INTERNATIONAL
TELEGRAPH AND TELEPHONE
CONSULTATIVE COMMITTEE
GENERAL ASPECTS OF DIGITAL
TRANSMISSION SYSTEMS;
TERMINAL EQUIPMENTS
40, 32, 24, 16 kbit/s ADAPTIVE DIFFERENTIAL PULSE CODE MODULATION (ADPCM)
Recommendation G.726
Geneva, 1990
FOREWORD
The CCITT (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the International Telecommunication Union (ITU). CCITT is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis.
The Plenary Assembly of CCITT which meets every four years, establishes the topics for study and approves Recommendations prepared by its Study Groups. The approval of Recommendations by the members of CCITT between Plenary Assemblies is covered by the procedure laid down in CCITT Resolution No. 2 (Melbourne, 1988).
Recommendation G.726 was prepared by Study Group XV and was approved under the Resolution No. 2 procedure on the 14 of December 1990.
___________________
CCITT NOTE
In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication Administration and a recognized private operating agency.
ã ITU 1990
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