G.723.1 Vocoder with Switchable Transmission Rates

This G.723.1 dual rate speech coder performs compression and decompression of 8 kHz speech signals. It encodes 16-bit PCM samples into 16-bit code-words yielding 10 or 12 code-words per 240 sample frames for the 5.3 kbps and 6.3 kbps channels respectively.

GAO\\\'s G.723.1 software has switchable transmission rates over 5.3 or 6.3 kbps channels providing 4 kHz of quality speech bandwidth in conformance with the ITU-T standard. The higher bit rate has greater quality; the lower bit rate gives good quality and provides system designers with additional flexibility.

The ITU-T G.723.1 standard specifies a coded representation that can be used for compressing the speech or other audio signal component of multimedia services at a very low bit rate as part of the overall H.324 family of standards.

It encodes speech or other audio signals in frames using linear predictive analysis-by-synthesis coding. The excitation signal for the high rate coder is Multipulse Maximum Likelihood Quantization (MP-MLQ) and for the low rate coder is Algebraic-Code-Excited Linear-Prediction (ACELP).

Additionally, Silence Compression Scheme and Voice Activity Detection (VAD) are also included in this version.

This G.723.1 vocoder belongs to GAO\\\'s family of Speech Vocoders. This line includes a wide variety of vocoders such as G.722.1 Vocoder and 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.

About GAO Research Inc.
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.