Method and apparatus for positioning microfiche card

摘要

A microfiche reader is provided with pulse motors which move a microfiche card in X and Y direction so as to position a required frame image on the microfiche card in an optical projection path. Using the symbol AF for the maximum number of frames recordable on the microfiche card, the symbol AS for the maximum number of pulse signals required to move the microfiche card from the datum position to the limit position, and the symbol PF for the location number of a required frame, the address number NS of a required frame can be calculated according to the equation NS=PFxAS/AF The number MS of pulse signals required to move the microfiche card from a present position to the required position is obtained from the difference between the address number NS of the required frame and the address number OS of the frame actually in the optical projection path. Pulse signals corresponding to the number MS are generated to control a pulse motor.