Linear-Phase Filters for a Digital Data-Acquisition System Used in Underwater Sound Propagation Experiments

摘要

Four groups of linear-phase, low-pass filters have been designed and built to couple a hydrophone array to an A/D conversion system. The filters are characterized by a linear phase response in the useful frequency band, a low overshoot in the step response, and a transmission loss exceeding 40 dB within the first stopband octave. Some active circuitry has been employed to eliminate insertion losses, avoid impedance matching problems, and allow the possible insertion of equalizers. Filters in the same group are phase-matched between each other within less than 0.5 deg throughout the useful frequency range. (Author)