The scientific impact of signal quantization on Planck/LFI observations

The real data processing of the signal observed by the Planck Low Frequency Instrument (LFI) introduces systematic effects in the time ordered data (TOD), maps and, finally, in the reconstruction of the sky angular power spectrum C_lsky. With analytical and numerical methods we studied the signal quantization of LFI TOD in order to evaluate the possibility to model and remove its effect on the C_lsky recovery. We find that it introduces a power excess, C_lex, only weakly dependent on the multipole l at middle and large l. It can be quite accurately subtracted, leaving an uncertainty, Delta C_lex, of only 1-2% of the RMS uncertainty, Delta C_lnoise, on C_lsky reconstruction due to the noise power, C_lnoise.