A variable displacement electro-hydraulic pump is operated in a closed loop position control circuit. The adjusting pistons at the adjusting member of the pump are controlled for that purpose by a control valve (20) that in turn is driven by a control amplifier (28). The adjustment path of the control valve and the adjustment path of the adjusting member of the pump are supplied as real values to this control amplifier (28). In addition, an adjusting signal that depends on the angle of rotation of the pump is generated at the control amplifier. This additional pulse-shaped adjusting signal allows the oscillating effects of the driving unit forces on the hydraulic fixation, as well as the resulting noises to be compensated.