Here is a simplified summary of the various speech coders used in mobile communication systems with their respective rates. The famous GSM uses the RPE-LTP that is the residual pulse excited linear long term predicting coder, which 13 Kbps of speech, the CD-900 in not very popular. Then US Digital Communication system using the IS-54 in their cellular mode they use the VSELP, that is a vector some excited linear predictor with 8 Kbps. Similarly the IS-95 uses variable bit rates 1.2, 2.4, 4.8 and 9.6 using the code excited linear predictor and, similarly, the depth uses the ADPCM at 32 Kbps. And the PACS, that is the personal access communication system also uses the ADPCM using 32 Kbps.

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