| 摘要 |
1. A digital telecommunications system comprising a crosstalk- and/or echo compensation circuit which is arranged between a four-wire line transmitting arm (VS), in particular the four-wire line arm incoming into a hybrid circuit (G), and a four-wire line receiving arm (VE), in particular the four-wire line arm outgoing from the hybrid circuit (G), and comprising a compensation signal store (KS) which can be operated in accordance with transmitted signal pulses occurring in the incoming four-wire line arm, where the crosstalk- and/or echo signal which occurs in the outgoing four-wire line arm as a result of a transmitted signal pulse occurring in the incoming four-line arm is input into the compensation signal store (KS) and, during a signal transmission, in response to each transmitted signal pulse, is read out therefrom as compensation signal, characterised in that the compensation signal store (KS) comprises a plurality (r) of circulating shift registers (UR), each of which has a circulation time equal to n-times (where n = 1, 2, 3 ...) a transmission signal bit time interval (tau 0 ) and a corresponding number n of outputs which follow one another at intervals corresponding to a transmission signal bit time interval (tau 0 ) and which are combined by a following evaluation- and addition circuit (ADD), into which circulating shift registers partial-compensation signals, obtained in the course of a series of isolated transmitted signal pulses, are input, where the echo- and/or crosstalk signal which directly corresponds to a transmitted signal pulse is input, in quantised and coded form, into the first circulating shift register (UR1) as partial-compensation signal and into the following circulating shift registers (..., URr) is input successively the respective echo and/or crosstalk signal, which has been sub-compensated by the partial-compensation signal(s) already input into a circulating shift register (UR1, ...), as further partial-compensation signal. |
