A sample of 64 well-calibrated pulsar polarization profiles measured at cm-wavelengths with the Effelsberg radio telescope is presented. All profiles were measured using an adding and a multiplying polarimeter which enables polarimetry over wide-bandwidths. Gain imbalances introduced by the active components in the signal path, as well as system imperfections, alter the polarization state of the incoming radiation. An analysis of the signal path of those devices is presented, together with a dynamic calibration procedure introduced to eliminate the instrumental errors. The results were used to trace the location of the radiating region in pulsar magnetospheres at high frequencies.