Echounterdrückungseinrichtung zum Unterdrücken von Echos in einer Sender/Empfänger-Einheit

摘要

An echo cancellation device (ECD) comprises an echo canceller (EC) including a transfer function estimator (EST, H) and a subtractor (ADD) and a residual echo suppression device (G, ADD2). The residual echo suppression device (G) comprises a residual echo filter (G) having an adjustable filter function (g). This filter function (g) can be adapted to either remove from the subtractor output (TNE') of the subtractor (ADD) the spectral characteristics relating to the reception signal (RFE) and/or to emphasize in the subtractor output signal (TNE') of the subtractor (ADD) a background signal spectral content relating to the transmission signal (TNE) generated by an transmitting unit (MC, TCRT). A noise generation means (NGM') can be provided at the output of the adaptable filter (G) for injecting a noise process in to the filter output signal (TNE') prior to a speech coding in a speech coder (COD). The noise process masks in the filter output signal a spectral content relating to the reception signal (RFE). The echo cancellation devices (ECD) according to the invention provide the advantage of an improved residual echo cancellation where there is no necessity to change code words or to bypass the echo canceller (EC).