SAMPLING AND RECOVERING ELECTRONIC SIGNALS: A CLASSROOM-LABORATORY INTEGRATION EXPERIENCE

In the Industrial Electronics Engineering graduate degree courses students should learn how to correctly digitalize analog electronic signals in order to avoid any loss of information carried by the analog signal. This digitalization involves the sampling of the original analog signal and, therefore, the teaching process has to be connected to the Sampling Theorem and to the concept of frequency spectrums of both the original and the sampled signals. Besides, the recovering of the original signal from the digitalized one implies the design of electronic filters making to some degree the whole teaching process somewhat long and complex. Searching for a better and quicker understanding, and taking into account that Power Point slides do not give a fast and clear thorough view of how the different parameters (value of sampling frequency-signal frequency ratio (fs/fa), cutoff frequency of the filter (fc), filter’s order (n)) affect to the sampling and recovering of the signal, the autor first of all made a simulation of the sampling and recovering circuits using electronic simulation software well known and available for the students so that it can be used in the classroom. In order to give access to the simulation via the Internet, the author used the Moodle platform to share the simulation archives with the students. But, what if the students could see in the classroom a demo using a real electronic circuit in wich all the aforementioned parameters could be changed? To do so the author designed a low cost portable electronic circuit (battery powered) in which fs/fa, fc, and n can be changed. Using this circuit in the classroom the frontiers between classroom and laboratory soften up allowing to see immediately the effects of any change in the circuit’s parameters on the accuracy of the sampled and recovered signals and, therefore, giving the necessary degree of interactivity for a better and detailed understanding of the digitalization and recovering processes.