G.711 Vocoder

GAO’s G.711 vocoder provides a compression /decompression (companding) algorithm to deliver precision transmissions of encoded speech signals sampled at the rate of 8 kHz in conformance with the ITU-T G.711 standard. GAO’s G.711 implementation includes independent user-callable functions that perform all of the μ-law and A-law encoding and decoding operations. The most common application for GAO’s G.711 vocoder is in telephone networks.

The G.711 standard uses pulse code modulation (PCM) to compress, decompress, encode, and decode analog speech, which can then be transmitted and received as binary data. Two forms of companding standards, the µ-law and the A-law, are specified. G.711 μ-law compresses frames of 14-bit linear PCM samples into frames of 8-bit logarithmic PCM code words. G.711 A-law compresses 13-bit linear PCM samples into 8-bit logarithmic PCM code words.