Abstract: A pulsed optical storage system including: rotatable storage means; means for projecting a beam of radiation at the surface of the storage means; means for moving the means for projecting transversely relative to the surface of the storage means; means for sensing the position of the means for projecting relative to the storage means; a radiation source for providing radiation to said means for projecting, including a radiation element, and a switching circuit in close proximity to said radiation element for selectively energizing the radiation element; and a control circuit responsive to the means for sensing for selectively enabling the switching circuit to energize the radiation element to produce pulses of radiation to the means for projecting.

Abstract: A system for determining the range between a reference point and a target by transmitting a pulse toward the target and measuring the time until receipt of a pulse reflected by the target. In an airborne laser altimeter configuration, the reference point may be located on an aircraft and a pulsed laser is directed along a vertical path to the ground. The system measures the duration of a pulse sequence including a first (or start) pulse, representing a pulse transmitted from the reference point, and the last of one or more associated subsequent return pulses, where the return pulses represent reflections of the transmitted pulse from both the ground and interfering objects located between the reference point and the ground. The system generates a replica of the start pulse and subsequent pulses, with the replica being delayed by a predetermined period from the start pulse and associated subsequent return pulses.