The Farey-dictionary for sparse representation of periodic signals

A finite duration sequence exhibiting periodicities does not in general admit a sparse representation in terms of the DFT basis unless the period is a divisor of the duration. This paper develops a dictionary called the Farey dictionary for the efficient representation of such sequences. It is shown herein that this representation is especially useful for identifying hidden periodicities in a finite data record. The properties of the Farey dictionary are studied, and the dictionary is shown to be superior to the conventional DFT based uniform dictionary, from the view point of identifying hidden periods.