The present invention relates to an analog predistorter (100) having a
tunable amplitude (60) and/or phase (80) expansion. The predistorter
(100) includes a coupler (110) having an input port (112), an output port
(114), a first (116) and a second (118) coupled port separated by 90
degrees. A first compensation circuit (120A) is connected to the first
coupled port (116) and comprises a first combination (130A) of linear
(132A) and nonlinear (131A) circuit elements and a first impedance
adjusting unit (140A) for adjusting the impedance seen by the nonlinear
circuit element (131A). A second compensation circuit (120B) is connected
to the second coupled port (118) and comprises a second combination
(130B) of linear (132B) and nonlinear (131B) circuit elements a second
impedance adjusting unit (140B) for adjusting the impedance seen by said
nonlinear circuit element (131B). By adjusting the impedances seen by the
nonlinear circuit elements (13 IA, 131B) the amplitude (60) and/or phase
(80) expansion of the predisorter (100) are tuned.