Method for echo suppression for a hybrid circuit

摘要

In a method for echo suppression for a hybrid circuit used to connect a four-wire line to a two-wire line, data signals passing from the incoming four-wire arm onto the outgoing four-wire arm as a result of the imperfect balancing of the hybrid circuit being corrected by means of a corresponding correction signal, first a positive and then a negative test pulse are injected into the four-wire input arm of the hybrid circuit and the echo signals occurring on the four-wire output arm of the hybrid circuit are evaluated. A mean value is formed from the two synchronous samples of the echo signals following inversion of the echo signal generated by the negative test pulse and this mean value is stored in a coefficient memory. The correction signal is then calculated with the aid of the contents of the coefficient memory.