Abstract: The invention comprises a digital frequency generator particularly adapted for use with acousto-optical scanning devices, and particularly for such devices as for producing a scan or a raster scan or the like. The invention electronic circuitry includes a precision timing generator which is made up of a tapped delay line which feeds a multiplexor to produce an output pulse of any desired configuration. The output pulses are produced in a stream, but each pulse is produced individually.

Abstract: A system for tracking a randomly moving object using a laser beam and first and second beam steering assemblies. The steering assemblies pivot, respectively, about substantially perpendicular and intersecting X and Y axes and direct the laser beam along an R axis, which is perpendicular to the X axis and intersects the X and Y axes. Along the R axis, the laser beam is intercepted by a retroreflector, which is coupled to the moving object and which returns the laser beam to a quadrant detector via the steering assemblies. The quadrant detector generates an error signal representative of the object's movement relative to the X and Y axes, and this signal is transmitted to two motors which pivot the steering assemblies about the X and Y axes to reduce the error to zero. The system includes an interferometer to determine the distance of the object from a reference location. The first beam steering assembly includes two prisms which redirect the laser beam through three 90.degree.

Abstract: A system for tracking a random seam on a surface for the purposes of, for example, welding or inspecting the seam. The sensing assembly in the system comprises a laser and a scattered light detector. The beam from the laser is scanned across the seam via an acousto-optical deflector in the range of 170-2100 scans per second, thereby providing accurate tracking of the seam while allowing the system to move longitudinally along the seam in the range of 3.3 to 10 inches per second. The scanning width is reduced, or windowed, to decrease the amount of data received by the detector and the system's overall control system to allow the higher speeds in the range while maintaining the desired tracking accuracy by decreasing data processing time.