Echo cancellation

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In electronics , telecommunications and data transmission, echo compensation is the term used to describe processes for suppressing or eliminating echo or hall effects while simultaneously sending and receiving ( duplex ) signals . In the telecommunications echo cancellation is also called echo cancellation referred.

For example, when making a phone call with a hands-free system , the voice from the loudspeaker reaches the microphone again and is transmitted back. The participant at the other end thus hears the echo of his own voice. Something similar can also be caused by induction or capacitive effects during data transmission ( crosstalk ) in electrical conductors and electronic components. To prevent this, echo compensation is used.

A simple echo suppression ('echo suppression') can be achieved using special filters , but echo cancellation (' echo cancellation ' by subtracting the estimated echo signal) is much better . Processes for echo compensation and interference signal suppression are mostly implemented today in corresponding signal processors .

In a more general sense, echo cancellation is a method to separate the two directions of signal transmission in duplex operation via a common medium (e.g. the air of the listening room from the above example of the hands-free system or the telecommunication lines in ISDN ).

See also