Patent ID: 6498850
Filing Date: 2002-12-24
Classification: H04B

Abstract:
A compander circuit (20) for echo cancellation in telecommunications apparatus, such as terminals, transmission systems, or switching equipment, having an input xâ€²1, at which a send signal sent from a near-end subscriber (1) to a far-end subscriber (2) is applied, an input xâ€²2, at which a receive signal zin(k) coming from the far-end subscriber (2) and a far-end echo, consisting of one or more component echoes, are applied, an output yâ€²1, at which the receive signal zout(k) processed in the compander circuit (20) is passed on to the near-end subscriber (1), an estimator module (21) for estimating an echo coupling and a delay of a line echo, and a characteristic module (23) with an associated multiplier (24) for controlling the short-time output level of zout(k) as a function of the short-time input level of zin(k), whereinat all inputs and outputs of the compander circuit (20), a plurality of N communications channels are applied and outputted, respectively, at an N-fold clock rate as compared with a single communications channel; all memory units in the compander circuit (20) are designed as multiplexer-buffer-demultiplexer (MBD) units (30); and a modulo-N counter (26) is provided which controls all MBD units (30) in such a manner that in each of the MBD units (30), always the same memory cell (351, 352, 35N) assigned to a particular communications channel is addressed.