WIDE BAND SYNTHESIS THROUGH EXTENSION MATRIX

The invention describes a system that generates a wide band signal (100-7000 Hz) from a telephony band (or narrow band: 300-3400 Hz) speech signal to obtain an extended band speech signal (100-3400 Hz). This technique is particularly advantageous since it increases signal naturalness and listening comfort with keeping compatibility with all current telephony systems. The described technique is inspired on Linear Predictive speech coders. The speech signal is thus split into a spectral envelope and a short-term residual signal. Both signals are extended separately and recombined to create an extended band signal.