Terminal apparatus for full-duplex data transmission having an echo canceller

摘要

A terminal apparatus for full duplex transmission of digital data comprising an echo canceler having FIR and IIR type filters and also comprising a filter convergence controller. The filter convergence controller performs its converging operation over both filters in a first duration of a communication starting sequence from the start of transmission from a local terminal to a remote terminal to the detection of the convergence of the echo canceller to a certain extent, stops the converging operation of the IIR type filter in a second duration of the communication starting sequence from the detection of the convergence to the detection of synchronization with the remote terminal, and again performs the converging operation of the both filters in a third duration after the detection of the synchronization.