An encoder generating a decoded signal with an improved quality by scalable encoding by canceling the characteristic inherent to the encoder and causing degradation of quality of the decoded signal. The resonance frequency of the resonator is tunable by changing a distance between a) an outer plate and b) a ceramic disc and an end cap where the ceramic disc is located between the outer plate and the end cap. In one embodiment, a logical field may represent an aggregate data value calculated from the elements appearing in a column of a relational table in an underlying physical data source.