公开(公告)号：DE3070149D1

公开(公告)日：1985-03-28

申请号：DE3070149

申请日：1980-06-24

Applicant: IBM

Inventor： CULLUM CLIFTON D ,  THOMPSON DAVID A ,  WORTHINGTON THOMAS K

IPC: G01B17/00 ,  G01D5/247 ,  G01D5/48 ,  G06F3/033 ,  G06F3/043 ,  G08C13/00 ,  H03H9/30

Abstract: A magnetostrictive wire (10) is provided at one end thereof with a pulse sensor (161) having an appropriate set (Barker sequence) of coils connected in series which are adapted to pick up an encoded train of magnetoacoustic signals. A position signaling electromagnetic drive head (141) is moved along the wire (10) to any desired position. The head (141) is pulsed to produce the encoded sequence of acoustic pulses in the wire (10). When those pulses are received by the sensor (161), a large pulse is produced at one time position of the waves as they pass through its sequence of coils. This large signal is used in conjunction with a timer (26-19) to provide position measurement. A second pulse sensor (162) makes it possible for a microprocessor (210) to provide self-calibration against thermal drifts in accuracy as well as immediate warning of invalid readings.