Improvements for the RPE-LTP Speech Codec

J. Valdés and A. Herrera (Mexico)


Speech Coding, Analysis by Synthesis, Most test, Speech Pre-processing, GSM, RPE-LTP.


The main purpose of this paper is to present some made modifications to standard RPE-LTP codec used in the actual GSM cellular telephony without modifying its structure and therefore without altering the bit rate. The original standard RPE-LTP and three modifications were simulated with a computer software and tested with a subjective quality measurement using the MOS (Mean Opinion Score) test. The modified techniques result in sound quality improvements when we compare them with the original standard.

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