Loss-Tolerant Speech Codec

A coder/decoder system (codec) is being developed for use in a digital voice communication system in which speech is encoded as a series of frames of data and transmitted over a noisy or lossy channel. Called a “loss-tolerant speech codec” (LTSC), the system is designed to maintain the quality of reconstructed speech at the receiver (decoder) when frames are occasionally lost or corrupted by noise during propagation through the channel. Digital satellite and digital cellular telephone links are typical examples of channels in which frames can be lost or corrupted by noise. In addition, variable frame delays in packet-switching digital communication channels can occasionally become long enough to exert the same effect upon speech decoders as that of loss of speech during the affected frames.