Abstract: A fiber optic-type shock wave sensor automatically adapts itself in response to vibration preventing false shock wave detection signals. The sensor includes a sensor element comprising a pair of mating toothed rings and a fiber optic coil disposed between the teeth of the rings. One of the toothed rings is moveable in response to shock waves to cause a bending of the fiber optic coil which detectably alters its light transmission characteristics. A rigid, dome shaped membrane is attached to the moveable ring and is flexibly attached to a body containing the sensor element. The membrane and body form an enclosure for the sensor element, and an aperture is disposed in the body which communicates with the enclosure. A normally closed spring biased check valve covers the aperture, and opens in response to a reduction in pressure in the enclosure to admit additional air or gas to the same.

Abstract: An LCD is provided for optical communication between a high frequency transducer and monitoring circuitry. The LCD modulates a light signal supplied by the monitor circuitry. The LCD is driven by the combination of two signals, a first signal representative of the parameter sensed by the transducer and a second, reference signal.