The AMR speech coder consists of the multi-rate speech coder, a source controlled rate scheme including a voice
activity detector and a comfort noise generation system, and an error concealment mechansim to combat the effects of
transmission errors and lost packets.
The multi-rate speech coder is a single integrated speech codec with eight source rates from 4.75 kbit/s to 12.2 kbit/s,
and a low rate background noise encoding mode. The speech coder is capable of switching its bit-rate every 20 ms
speech frame upon command.
This TS is an introduction to the speech processing parts of the narrowband telephony speech service employing the Adaptive Multi-Rate (AMR) speech coder. A general overview of the speech processing functions is given, with reference to the documents where each function is specified in detail.
full Table of Contents for TS 26.071 Word version: 15.0.0