The aim of this paper is to show how the noise reduction by signal accumulation can be accomplished with a data acquisition system. This topic can be used for student projects. In many cases, the noise reduction is an unavoidable part of experimentation. Several techniques are known for this purpose, and among them the signal accumulation is the simplest one. It is based on exactly knowing the period of a signal to be expected. This is possible when the signal is a response to periodic changes of some external parameters set by the experimenter. For instance, the sample may be subjected to periodic changes of temperature, pressure, irradiation, magnetic or electric field, etc. Therefore, the response of the sample is of exactly the same periodicity as the external influence. A source of this influence provides a signal strictly defining the period of the signal.