Abstract: A fiber optic sensor array includes a row of transmitting optical fibers, with a column of detecting optical fibers overlapping the transmitting fibers. A planar compliant spacer separates the transmitting fibers from the detecting fibers, so that a sensor element is defined at each location where a detecting fiber overlaps a transmitting fiber. The surfaces of each transmitting fiber and each receiving fiber are modified at the location of each sensor element to increase the optical coupling between the transmitting fiber and the receiving fiber at that element. The spacer in the array includes an opening between the transmitting fiber and the detecting fiber at the location of each sensor element. A support surface is affixed to the detecting fibers opposite the compliant spacer and a protective cover layer is affixed to the transmitting fibers opposite the compliant spacer.

Abstract: A method and apparatus is disclosed for calibrating an ultrasonic inspection system having a plurality of transducers (12a, 12b, 12c) coupled by a common amplifier (16) to a distance-amplitude correction (D-AC) circuit comprised of a multiplying digital-to-analog converter (26') which receives, as a function of the transit time of an ultrasonic signal measured by a clock counter (34), a D-AC correction stored in a look-up table in a random access memory (24'). The D-AC correction function stored in the look-up table for each transducer is the inverse of a return signal response curve determined by measuring the peak amplitude of return signals from calibration holes at known depths in a test block (10) while in a calibrate mode, i.e., with a switch (SW) in a state to bypass the MDAC.

Abstract: An apparatus and method for automatically monitoring dynamic signals, such as from vibration sensors, in an operating industrial or other plant to identify abnormal events, draw conclusions as to their severity, and indicate action to be taken, utilizing a computer to control the scanning of one or two sensor channels at a time through a matrix of analog switches, and to process one or two channel signals through a signal processor for power spectral density (PSD) analysis (two channel signals for cross PSD analysis). The computer compares spectra with predetermined sets of frequency dependent limits and indicates the abnormal condition of apparatus in the plant associated with the spectra as a function of which set of limits is exceeded. The computer also indicates from a stored table the action to be taken for the abnormal condition found.