| 摘要 |
Adaptive predistortion circuit for a digital transmission system which comprises:… . a predistortion circuit (521, 522, 523) which predistorts the input data before they pass into a modulator (56) and then into an amplifier (57),… . and an adapting circuit (611, 622, 613) which, from a demodulation of the flow of transmitted data, continuously adapts the predistortion circuit to the flow of the input data. …<??>It comprises an encoding circuit (51) which, from the digital data ak, generates, on a first channel, digital data bk which leave predistorted from a first predistortion circuit (52) in phase with the clock pulse, on a second channel, digital data ck which leave predistorted from a second predistortion circuit (522) phase-shifted by T/3 from the clock pulse and, on a third channel, digital data dk which leave predistorted from a third predistortion circuit (523) phase-shifted by 2 T/3 from the clock pulse. The signals bk, ck and dk are obtained by a polynomial encoding. The encoding may be carried out with the aid of shift registers (621 ... 62i) addressing a memory (63) or by means of a transversal filter (711, 712, 713). It may also be obtained with the aid of an analog output filter (81) followed by samplers (821, 822, 823). …<??>Application: digital transmission systems. …<IMAGE>… |
