ITU G.727:1990
ITU G.727:1990 5-, 4-, 3- And 2-bits/sample Embedded Adaptive Differential Pulse Code Modulation (adpcm)
Table of Contents
1Introduction2General
3EmbeddedADPCMalgorithms
3.1ADPCMencoder
3.2ADPCMdecoder
3.3Onesdensityrequirements
3.4Applications
4ADPCMencoderprinciples
4.1InputPCMformatconversion
4.2Differencesignalcomputation
4.3Adaptivequantizer
4.4Bitmasking
4.5Inverseadaptivequantizer
4.6Quantizerscalefactoradaptation
4.7Adaptationspeedcontrol
4.8Adaptivepredictorandfeedbackreconstructed
signalcalculator
4.9Toneandtransitiondetector
5ADPCMdecoderprinciples
5.1Bitmasking
5.2Feedbackinverseadaptivequantizer
5.3Feed-forwardinverseadaptivequantizer
5.4Quantizerscalefactoradaptation
5.5Adaptationspeedcontrol
5.6Adaptivepredictorandfeedbackreconstructed
signalcalculatorinG.727
5.7Feed-forwardreconstructedsignalcalculator
5.8Toneandtransitiondetector
5.9OutputPCMformatconversion
5.10Synchronouscodingadjustment
6Computationaldetails
6.1Inputandoutputsignals
6.2Descriptionofvariablesanddetailed
specificationofsub-blocks
APPENDIXI-Digitaltestsequencesfortheverification
ofthealgorithms
I.1Purposeofdigitaltestsequences
I.2Disketteinterfaceandformat