[en] Highlights: • Systematic requirement analysis of the digitizing process. • Synthetic pulses with different Full Width Half Maximum (FWHM). • Statistical and systematic error study. • Effects of the pulse amplitude reduction respect to the full scale on the error. • Hardware architecture considerations. - Abstract: Nuclear radiation spectroscopy is now often relying on digital acquisition techniques. The present paper addresses the problem of analyzing the requirements of the digitizer in terms of sampling frequency and number of bits to minimize the energy resolution degradation caused by the digitizing process. The analysis is performed using synthetic pulses (with different amplitude and Full Width Half Maximum) of typical nuclear spectroscopy detectors and the pulse area as energy estimate. Additional relevant issues, such as the hardware architecture and the data throughput speed, are also discussed.