公开(公告)号：US3571685A

公开(公告)日：1971-03-23

申请号：US3571685D

申请日：1968-01-15

Applicant: IBM

Inventor： AKINS VAUGHN E ,  HARRIS JOHN P ,  KOST FREDERICK H

IPC: G05D3/20 ,  G11B15/093 ,  G11B27/13 ,  G05B19/28

CPC classification number: G05D3/20 ,  G11B15/093 ,  G11B27/13

Abstract: The physical displacement of a movable medium is indicated by the content of a bidirectional counter. The counter is incremented or decremented by direction-oriented pulses relating to movement of the medium, these pulses being selectively gated into the counter. The content of the counter can control an operational amplifier to provide an indication of the position of the medium relative to a null point represented by any selected count in the counter.