The paper is a case study for the management of a set of synthetic harmonic and real-world sampled signals analysed by various spectral methods at some desired orders. An OODBMS schema was preferred to an alternative RDBMS, exploiting the specific advantages of the object oriented-approach (direct correspondence between real-world and database objects, inheritance, transparent modularity-extendability-encapsulation, etc.) An extended entity relationship (EER) model is presented, which is transformed to an OODBMS schema. This schema is illustrated in detail, comprising class definitions code for the method bodies, persistence through linkage to persistent mamed roots, certain object definition and an example of an SQL-type query, all of them developed in the language O2.