This article presents the design and implementation of PBL tasks, for improving the understanding of sampling and reconstruction of signals. This implementation focuses on the execution of a mini project in the course of digital signal processing. The paper presents the backward design of theme in the course, the planning of the activities, and the results of the implementation. Likewise, it describes an analysis of the effects of PBL tasks on students' concepts, the obtained results demonstrate that they can solve problems of implementation in a different way.