Underwater Acoustics

ContentsPreface 1 Introduction and Background Discussion 1.1 The Propagation of Acoustic Signals in the Ocean 1.2 The Ocean Medium as an Underwater Acoustic Communication Channel Bibliography 2 Fundamentals of Linear, Time-Variant, Space-Variant Filters 2.1 Deterministic Filters 2.2 Random Filters Bibliography 3 Complex Apertures 3.1 Coupling the Transmitted and Received Signals to the Medium 3.2 Directivity Functions 3.3 Linear Apertures and Far-Field Directivity Functions 3.4 Linear Apertures and Near-Field Directivity Functions 3.5 Planar Apertures and Far-Field Directivity Functions 3.6 Planar Apertures and Near-Field Directivity Functions 3.7 Directivity Index Problems Bibliography 4 Arrays 4.1 Linear Arrays and Far-Field Directivity Functions 4.2 Linear Arrays and Near-Field Directivity Functions 4.3 Grating Lobes 4.4 Array Gain 4.5 Planar Arrays and Far-Field Directivity Functions 4.6 Planar Arrays and Near-Field Directivity Functions 4.7 Volume Arrays and Far-Field Directivity Functions Problems Bibliography 5 Signal Processing 5.1 FFT Beamforming for Planar Arrays 5.2 Complex Envelopes 5.3 The Auto-Ambiguity Function 5.4 Time-Compression-Stretch Factor, Time Delay, and Doppler Shift Expressions Problems Bibliography 6 Wave Propagation in Inhomogeneous Media 6.1 The WKB Approximation 6.2 Ray Acoustics 6.3 The Parabolic Equation Approximation Bibliography 7 Random Ocean Medium Transfer Functions 7.1 Coupling Equations and the Generalized Coherence Function 7.2 The WKB Approximation Revisited 7.3 The Parabolic Equation Approximation Revisited Bibliography Answers to ProblemsIndex