PREDISTORTION ARRANGEMENT FOR A DIGITAL TRANSMISSION SYSTEM

摘要

A predistortion arrangement (9) for a digital transmission system transmits complex input data of a constellation by means of a modulator (14) and a power amplifier (15) which distorts the data. The arrangement comprising a predistortion circuit (11) which predistorts the input data in opposite sense before they pass through the amplifier and a transmit filter (10) which applies oversampled filtered data encoded with 2N bits to the predistortion circuit (11) at the rate k/T. The predistortion circuit (11) is formed from an encoder (20) transforming the filtered 2N-bit encoded data into data encoded with 2M bits (M<N) which address a memory (51) that stores complex predistortion coefficients, and a complex multiplier (52) that multiplies for each data element the 2N bits of the filtered data element by the selected predistortion coefficient for producing predistorted data.