The problem to analize a file with 23000 discreet samples of an intercepted signal with noise included, which contains a codifided message was presented to us as a challenge. We apply the methodologies reviewed during the course of linear analysis systems for the development of this document, which consist in the process of an entrance document, decompose the document and apply the fast transform of fourier for better manipulation as a way to be able to rebuild the original signal and to identify the frecuencies throughout the 23 seconds signal. It was handed to us an equivalences table with which we finalize to associate the signal to a final message.