| 摘要 |
A method of compensating for non-linearities in an end amplifier (F) having a given transfer function H R, H.PHI. for amplitude and phase respectively and included in a radio transmitter of quadrature type for linear, digital modulation, and in which table look-up units (ST, CT) store the digital sine and cosine values (I(t,.alpha.), Q(t,.alpha.)) of the quadrature components determined by a given signal vector .alpha.. According to the method the values of the transfer functions H R, H.PHI. for the quadrature modulated radio signals r(t,.alpha.) are calculated by addressing memory units (MH1, MH2) which store a number of values of H R, H.PHI.. The sine and cosine values of the addressed values of H R, H.PHI. are also formed. The thus calculated values are multiplied by the stored digital values in the table look-up units (ST, CT) and by the inverted value of H R. As a result, new modified values i(t,.alpha.), q(t,.alpha.) are obtained for the quadrature components, which compensates for the non-linearities in the final amplifier.
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