Nokia Corporation

Mulsys Ltd

Stephane Villette

Ahmet Kondoz

Khaldoon Taha Al-Naimi

Kholdoon Taha Al-Naimi

Nilantha Nandima Katugampala

A system for transmitting input data over a speech channel of a network comprising: a modulator arranged to produce a modulated waveform signal transforming the data for transmission over the network; a channel compensation filter arranged to filter the modulated waveform signal after it has been transmitted over the speech channel to compensate for the response of the speech channel; and a demodulator arranged to retrieve the data from the filtered waveform signal.

Data transmission

To alleviate problems of signal aliasing and to reduce complexity, Linear Predictive Coefficients (LPCS) are calculated from samples of audio signals and Line Spectral Frequency (LSF) vectors are extracted from the LPCs with a rate higher than a desired vector rate, the LSF vectors comprising values of different LSF parameters. Next, an LSF track is formed for at least one of the LSF parameters. At least one of the formed LSF tracks is then low pass filtered. Finally, decimated LSF vectors are reconstructed from the low pass filtered LSF tracks, the decimated number corresponding to the desired vector rate. The invention equally relates to a corresponding computer program, to corresponding devices and to a corresponding communication network.

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Dissay sous Courcillon, France

Stephane Villette