G.726 Vocoder Applied to the PCM Bit Stream
Toronto, Canada – GAO Research Inc. (www.GAOResearch.com) is offering its G.726 Vocoder which is used in numerous applications such as speech transmission over digital networks, video conferencing, multimedia, and ISDN communications. GAO Research's G.726 vocoder complies with the ITU-T standard and operates at 40, 32, 24, and 16 kbps.It converts a 64 kbps A-law or μ-law PCM channel to or from a 40, 32, 24 or 16 kbps channel.The conversion is applied to the PCM bit stream using an ADPCM transcoding technique. Thus, the scheme has switchable transmission rates providing 4 kHz of audio bandwidth. ITU-T G.726 is a superset of the ITU-T G.721 and G.723 standards and was originally designed as a half-rate alternative to G.711 audio companding.G.726 can encode 13 or 14-bit PCM samples or 8-bit, A-law or μlaw encoded data into 2, 3, 4, or 5-bit code words.Since the algorithm encodes one sample at a time, the coding or decoding delay is effectively zero, providing for robust, quality audio. In addition, processing frame size and input/output formats is user selectable. This G.726 vocoder belongs to GAO’s family of Speech Vocoders. This line includes a wide variety of vocoders such as G.722.1 Vocoder,GSM-AMR (AMR-NB) Vocoderwhich is used mainly in 3rd generation mobile telephony devices to compress toll-quality speech at 8000 samples/secondand G.729, G.729A and G.729AB Speech Vocoder which is ideal for visual telephony, wireless communications, and digital satellite communication systems and other similar products. This line of vocoders complies with the ITU-T vocoder standards for speech processing software and audio processing codecs. About GAO Research Inc. GAO Research Inc. (www.GAOResearch.com) is a world-renowned provider of high quality, reliable telecommunications software including embedded modem software, fax modem software, speech codes, and telephony software for a wide range of DSPs and microprocessors.