Nokia Telecommunications Oy

Heimo Lahdemaki

Olli Liinamaa

Jussi Sarpola

Timo Kononen

Pertti Salonen

Vesa Sarkikangas

Jaakko Sippola

Method for remotely changing the telecommunication settings of a

System for transmitting charge information to a wireless subscriber via

A method of preventing an adaptive echo canceler from diverging in a noisy environment, including determining an average noise level (-45 dBmO) in the echo path, determining an attenuation (A.sub.e) of the echo path and preventing an adaptation of the echo canceller, if the level of the signal (x(i)) to be transmitted to the echo path and causing echo (r(i)) is lower than a predetermined threshold level, which is to the extent of a preset margin and the echo path attenuation above the average noise level.

Method of preventing a divergence of an adaptive echo canceller in a

The operation of an echo canceller (4A to 4D) is controlled by a call control (2) of a telephone exchange over an internal control bus (3, 5) of the telephone exchange. The exchange then attends to the necessary signalling and the echo canceller does not need to know how the associated signalling is routed in the telephone network.

Arrangement for the control of an echo canceller

Method for the detection of a disable tone signal of an echo canceller

Method for non-linear signal processing in an echo canceller

Converging of an echo canceller (4A-D) integrated into a telephone exchange (1, 2) is initiated at the start of a telephone call by an internal command of the telephone exchange given by a call control (2) of the telephone exchange as soon as the call control (2) has observed an off-hook state of a called subscriber connection. The command causes the echo canceller (4A-D) to transmit a test signal to the echo path for converging the echo canceller before appearance of the speech signal.

Method of converging an echo canceller

Growing community of inventors

Pirkkala, Finland

Heimo Lahdemaki