The article is aimed to provide reception algorithm as a whole with element-by-element decision making. It belongs to the group of decision, making algorithms with feedback. It is used to demodulate discrete signals that have passed through a memory channel. The study presents an example of signal processing of a binary phase modulator. This example shows processing features that are not obvious for considering of the mathematical formula that describes demodulation algorithm. Another algorithm was developed for a quadrature phase modulator as well. The noise immunity for additive gaussian noise was estimated by the numerical simulations. The same researches was carried out using an equalizer filter that suppresses channel memory effect. Simulation results were used as the base for the graphs of the error probability versus signal-to-noise ratio.