Performance of the integrated polarization measurements. Left panels: ratio between the polarized flux density P of the brightest simulated galaxy in the beam and the measured one in the P map. The symbols are the same as in Fig. 3. Central panels: same thing for the polarized fraction p. Right panels: difference between the polarization angle α of the brightest source in the beam (see Sect. 2.3) and the measured angle. The rows correspond to the various polarized band from PPI1 to PPI4.