Noise detector for ship propellers - uses acceleration pick=up amplifier and display with voltage corresp. to value above signing frequency as reference

摘要

The detector device for ship's propeller induced noises, includes an acceleration sensor (1), an amplifier and an indicator. The sensor detects any noise in the ambience and then transduces it into an electrical signal, and requires a constant current source (15) for its integrated MOSFET used to construct the signals via a coaxial cable to the detector installed at a selected point in the ship. The MOSFET arrangement provides a low-resistance output type impedance converter, with the constant current source (15) integrated into the detector, with current supply and signal voltage isolution provided via the coaxial cable. The detector input stage (2) is designed as a high-pass filter with its 3dB threshold at 450 Hz. USE - Military seacraft, e.g. mine sweepers propeller singing detection and minimisation preventing damage.