A predistortion control device (1). The device has a first predistortion control input connectable to a power amplifier output (21); a second predistortion control input (11) connectable to a signal contact of a predistortion device; and a predistortion control output (12) connectable to a control contact of the predistortion device. The predistortion control device (1) further includes a cross-correlator device (110). The cross-correlator device (110) is connected with a first cross-correlator input (1101, 1101I, 1101Q) to the first predistortion control input and a second cross-correlator input (1102, 1102I, 1102Q) to the second predistortion control input (11). The cross-correlator device (110) is further has a cross-correlator output (1112) at which a cross-correlation signal can be presented, the cross-correlation signal representing a measured cross-correlation of signals presented at the first cross-correlator input (1101, 1101I, 1101Q) and the second cross-correlator input (1102, 1102I, 1102Q). The predistortion control device (1) further has a predistortion function selector device (120)(120), connected with a selector input to the cross-correlator output (1112), and with a selector output to the predistortion control output (12), at which selector output a predistortion control signal can be presented. The predistortion control signal representing a predistortion function determined on the basis of said cross-correlator signal.