Applied Underwater Acoustics

11.3. Filtering

Filtering a measurement is often part of a formal detection or estimation process, but can be done for other reasons (e.g., an antialiasing LPF prior to temporal sampling or band-pass filtering prior to base-banding). Prior to temporal sampling, filter design and implementation is inherently analog and often situation specific. As the majority of filtering applications in underwater acoustics occur after sampling, the focus of this section is on discrete-time filters and generic filter types.

11.3.1. Filter Types

The most common filters simply isolate portions of the frequency spectrum. LPFs allow low-frequency signals through their pass band while rejecting spectral content at higher frequencies in the stop band. Fig. 11.3 shows ...