Abstract: A laser based accelerometer system uses small motion induced shifts in frequency to measure the motion of an object without contact thereof. This technique is particularly useful for determining the vibratory and velocity characteristics of objects that are otherwise inaccessible for direct motion measurement by contact sensors.

Abstract: A directional antenna system is disclosed which selectively couples two radiating antenna elements to a transceiver through a selective phase, magnitude and matching network which is controlled by the output of a logic circuit. The network provides for equal magnitude current coupling between the transceiver and the two antennas while simultaneously selectively producing either positive or negative approximately 90.degree. phase shifts between the two antennas to produce either of two discrete directive cardioid radiation patterns directed in substantially opposite directions. The logic circuit, in conjunction with a manual step switch, provides for a manually selecting either of the two cardioid radiation patterns, as well as producing a figure eight or an omnidirectional radiation pattern. For generating a transceiver omnidirectional pattern, one antenna is used and the other is connected to a standard broadcast band receiver.

Abstract: A system for detecting the presence of coherent radiation comprises an interference filter having a pair of partially-reflective mirrors. The spacing between the mirrors is varied in accordance with a sine function to change the transmission wavelength of the mirrors. A reference signal is developed which represents this periodic variation in the spacing of the mirrors. A photodetector on the output side of the filter detects radiation transmitted therethrough, yielding a detection signal in the presence of coherent radiation transmitted through the filter. An indicator responds to the signal output of the photodetector and to the reference signal to produce an identifying indication of the detected radiation.