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Vocoder aims for bandwidth-limited applications

Edited by the Electronicstalk editorial team Mar 14, 2003

An improved code-excited linear prediction (ICELP) vocoder for speech compression at 8Kbit/s is now available for licensing from Kane Computing.

An improved code-excited linear prediction (ICELP) vocoder for speech compression at 8Kbit/s is now available for licensing from Kane Computing.

The 8Kbit/s vocoder from Spirit Corp is a proprietary speech compression algorithm based on the well-known CELP model and strongly optimised, ensuring significant improvement of speech quality at low computational complexity.

This algorithm is extremely useful in a wide range of storage capacity and/or bandwidth sensitive applications such as multimedia devices, visual telephony, wireless telephony, secure telephony, and videoconferencing products.

Features of the 8Kbit/s ICELP vocoder include: high speech quality (MOS about 4.0); automatic built-in frame synchronisation and comfort noise generation (CNG); and direct interfacing with PCM 8kHz sampled data.

The code is re-entrant, supports multithreading and dynamic memory allocation.

The vocoder has a very simple application interface and can be easily ported to any DSP or RISC platform.

While claiming extreme cost effectiveness due to its proprietary nature the solution satisfies system requirements comparable with the ITU-T G.729 standard.

The 8Kbit/s ICELP vocoder is available in the form of object code for TI's TMS320C54x and C55x (coming soon) and also as a DLL for MS Windows.