Hitachi, Ltd.

Hideyuki Usami

Masataka Sekiya

Hisashi Ohta

Kiyoshi Hiramatsu

An auto-tracking system for a helical scan type magnetic recording/reproducing unit comprises a synchronizing signal separating circuit from video signals on a running magnetic tape reproduced by a rotary video head, a periodicity variation measuring and comparing circuit in the synchronizing signals separated in the synchronizing signal separating circuit, and a tracking control means which controls the running condition of the magnetic tape with reference to a phase difference between a reference signal in association with the rotary video head and a signal representing the running condition of the magnetic tape and changes tracking by a predetermined amount in response to the periodicity variation measured by the measuring and comparing circuit so as to minimize the periodicity variation measured by the same, thereby an optimum tracking position is obtained without being interfered by cross-talks between the adjacent tracks.

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Ibaraki, Japan

Hideyuki Usami