Abstract: Method for separating a mixture of source signals to regain said source signals, said method being based on measured signals. The method being characterized in, that every measured signal is brought to a separation structure comprising cross connected linear filters and subsequent adders, that cross correlation functions between the signals after said adders are calculated for delays k between a first delay K1 and a last delay K2, that a criterion function is used to determine how the linear filters comprised in said separation structure will be designed in every real situation, that said criterion function is formulated as a sum of terms where the addition is extended to all possible cross correlation functions between the output signals of separation structure at all possible delays (k) between K1 and K2, and that each term in said sum has a weight factor and another factor consisting of an even function, f, of a specific cross correlation function at a specific delay.

Abstract: A method of transmitting voice information from an electronic communications device (1) comprises the steps of receiving the voice information from the environment of the device together with a first background sound, generating a sound signal having a first signal part representing the voice information and a second signal part representing the first background sound, reducing the signal part representing the first background sound, and transmitting the sound signal through a communications channel to which the device is connected. The method further comprises the step of adding to the sound signal an additional signal representing a second background sound. In this way background noise can be removed, while a natural and comfortable conversation can be maintained without revealing the location of the user of the device.

Abstract: A system and method for speech signal enhancement upsamples a narrowband speech signal at a receiver to generate a wideband speech signal. The lower frequency range of the wideband speech signal is reproduced using the received narrowband speech signal. The received narrowband speech signal is analyzed to determine its formants and pitch information. The upper frequency range of the wideband speech signal is synthesized using information derived from the received narrowband speech signal.