This vocoder converts a 64Kbps A-law or μ-law PCM channel to or from a 40, 32, 24 or 16kbps channel.The conversion is applied to the PCM bit stream using an ADPCM transcoding technique. Thus, the scheme has switchable transmission rates providing 4kHz of audio bandwidth. It encodes 13 or 14-bit PCM samples or 8-bit, A-law or μ-law 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 zero which ensures robust, quality audio.
All GAO Research’s speech software has passed the test vectors specified by the ITU GAO also adheres to stringent quality control procedures, which is reflected in the well structured code, detailed design documentation, and well-defined design and test plans. This ensures ease of integration, easy maintenance and a smooth upgrade path for further generation customer products.
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GAO Research Inc.(www.GAOResearch.com) is a recognized international leading provider of communications software to telecom and electronics companies and provides the most comprehensive and unique suite of modem, fax, telephony, speech software, VoIP, FoIP, fax relay and fax/modem/voice relay software for embedded applications for DSP and microprocessors.
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