Detection of echo state in duplex transmission e.g. when using mobile phone system, is achieved by monitoring adaptive filter coefficient update, which reveals phantom signal presence on exceeding threshold

摘要

An adaptive filter is connected to receive the remote signal with corrupting echo. Its coefficients are updated. Filter coefficient variance is calculated. Should the variance reach a threshold value, presence of the phantom (or echoed) speech state is established. An Independent claim is included for the control unit carrying out the method.