| abstract |
A system for monitoring vibrations in a target region of interest may include a pulsed laser transmitter assembly, interferometric, telescope, and receiver optics, a photo-EMF detector assembly, signal conditioning/processing electronics, and a monitoring circuit/display. The detector assembly, which has a photo-EMF detector and amplifier circuits, generates an output signal indicative of the vibrations. A laser module outputs a source beam at a PRF of at least 2 Hz. A beam splitter device splits the source beam into separate interrogating and reference beams. The mirror directs the reference beam onto the photo-EMF detector for interference with a reflected return signal. The telescope optics generates an amplified return signal, and directs the amplified return signal to the photo-emf detector. The monitoring computer compares the output signal from the signal processor to a baseline to ascertain a difference therebetween, and generates a diagnostic signal indicative of the difference. |