Siemens Schweiz Ag

Peter Gysel

Bruno Wenger

August Kaelin

Daniel Mueller

August Kalin

Send filter for an echo canceler. A circuit includes a send path carrying a send signal, a receiver path carrying a received signal, an adaptive filter, a compensator contained in the received path, a digital/analog converter, a transmission unit, and a transmission line attached to the transmission unit, wherein over the transmission line, at least the send signal, the received signal, the echo signal portions are transmitted, and the send and received path are additionally connected with the transmission unit and the send signal is transmitted to the adaptive filter for the estimation of the echo signal which is processed in the compensator for the production of the receiving signal, with the send signal being conveyed, on the send path, to digital/analog converter, which, with the symbol rate of the send signal, produces square pulses, which in turn are transformed, in the send filter, connected with the digital/analog converter, into pulse forms useable for transmission via the transmission line, with the send filter being so conceived that the digital/analog converter merely has a resolution of two bits, whereby non-identities, particularly non-linearities, are compensated with the aid of the adaptive filter, the latter including at least one FIR filter portion of the storage compensation type.

Send filter for an echo canceler

Echo canceler. A circuit arrangement for the cancellation of echo signals, wherein in the received path, an analog/digital converter is connected with a first adder and a second adder is interposed after the analog/digital converter, with the estimated echo signal being divided into first and second portions, whereby the first portion is transmitted to the first adder and the second portion is transmitted to the second adder for the production of the received signal. In a further embodiment, a third adder is interposed between the analog/digital converter and the second adder, via which the output signal of a compensation filter is added to the signal in the received path.

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Zurich, Switzerland

Peter Gysel