| 摘要 |
PCT No. PCT/SE82/00363 Sec. 371 Date Jun. 16, 1983 Sec. 102(e) Date Jun. 16, 1983 PCT Filed Nov. 2, 1982 PCT Pub. No. WO83/01716 PCT Pub. Date May 11, 1983.A method and an apparatus, in a telecommunication system for transmission of digital information in duplex over a signal conductor pair for automatically adjusting a balance filter included in a hybrid coupler circuit with the aid of adaptive echo cancellation so that the local data transmitter does not disturb the local data reception, without utilizing any particular testing procedure in initiating the adaptive echo cancellation. A control signal ( epsilon k) is formed, with the help of which the correction unit (KB) is caused to generate signals for rapid updating of the balance filter (B) parameters, in spite of that knowledge is lacking in the initiation instant concerning the value of the signal transmitted from the remote end to the apparatus, and that no counteraction between level correction and filter adaption is obtained. The apparatus includes a quantizer (Q) in which a sampled, received signal (rk) is quantized, an estimated signal (âk) of data sent from the remote end being obtained. Said estimated signal is multiplied by a reference signal from a reference unit (V), the result being subtracted from the received signal (rk) so that an error signal (e k) is formed. The sign of the error signal is correlated with the estimated signal (âk) in a correction unit (KV), which calculates a correction ( DELTA V) which is added to the reference signal in order to correct it. The sign of the error signal (ek) is also added to the estimated signal (âk) thereby forming said control signal ( epsilon k) which is correlated with the data vector (bk) in the correction unit (KB) which calculates a correction value ( DELTA c) which is supplied to the input of the balance filter for correction of the filter parameters. |
