Abstract: An audio filtering and power extraction apparatus for filtering out audio signal and extracting power from a combined signal and direct-current power line, with an input configured to couple to a combined signal and direct-current power line, a filtering extractor system functionally coupled to the input, a DC sensing switch circuit, and a second order low-pass filter functionally coupled to the DC sensing switch circuit, the second order low-pass filter including, an inductor, a capacitor and resistor in series with each other, and an output functionally coupled to an output of the filtering extractor system and through which output extracted power is provided.

Abstract: Trajectory estimate for a sub-sonic projectile can be derived from sampling a wake contribution of an acoustic signal detected at a multi-detector array. The wake contribution is sampled, in time, and the samples are processed to determine a bearing estimate for the projectile from which the acoustic wake derives.

Abstract: Detection of a trajectory of a supersonic projectile is carried out derived from a plurality of acoustic detection signals. From these acoustic detection signals, two or more shockwave-derived trajectory estimates can be derived. Further, a wake derived trajectory bearing estimate can be derived, from which disambiguation of the shockwave-derived trajectory estimates can be effected.

Abstract: Trajectory estimate for a sub-sonic projectile can be derived from sampling a wake contribution of an acoustic signal detected at a multi-detector array. The wake contribution is sampled, in time, and the samples are processed to determine a bearing estimate for the projectile from which the acoustic wake derives.

Abstract: Detection of a trajectory of a supersonic projectile is carried out derived from a plurality of acoustic detection signals. From these acoustic detection signals, two or more shockwave-derived trajectory estimates can be derived. Further, a wake derived trajectory bearing estimate can be derived, from which disambiguation of the shockwave-derived trajectory estimates can be effected.

Abstract: An acoustic detector provides a planar arrangement of microphones. A windshield is arranged over the microphones, with a view to reducing the impact of environmental effects. A void is therefore defined over the microphones, and the interior surface of the windshield, which defines the void, is shaped suitably to reduce the potential for acoustic waves propagating within the void to reflect back onto the microphones.

Abstract: An acoustic detector provides a planar arrangement of microphones. A windshield is arranged over the microphones, with a view to reducing the impact of environmental effects. A void is therefore defined over the microphones, and the interior surface of the windshield, which defines the void, is shaped suitably to reduce the potential for acoustic waves propagating within the void to reflect back onto the microphones.