SYSTEM FOR CONTROLLING POSITIONS OF RECORD TRACKS RELATIVE TO A SCANNING TRACE OF A HEAD DEVICE

摘要

A system is provided for controlling positions of record tracks relative to a scanning trace of a head device (12A;12B). An envelope detector (36) detects an envelope of an output from a head device (12A;12B) operative to scan a record tape (13) along a scanning path transverse to record tracks. A pulse generator (40) produces two pulses appearing respectively at predetermined time points in a period of a scanning trace of the head device (12A;12B). A level sampler (37) samples a level of a detection output from the envelope detector (36) with the pulses produced by the pulse generator (40) to produce two sampled outputs. A dislocation detector (41) detects dislocation of a group of record tracks traversed by the head device (12A;12B) relative to the scanning trace of the head device (12A;12B) based on a difference between the sampled outputs from the level sampler (37). A tape controller (42,45) adjusts a travelling speed of the record tape (13) to control positions of the record tracks traversed by the head device (12A;12B) relative to the scanning trace of the head device (12A;12B) in response to a detection output from the dislocation detecting circuit (41). IMAGE