The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 07, 1986
Filed:
Mar. 19, 1984
Motohiko Takeuchi, Yokohama, JP;
Tokyo Shibaura Denki Kabushiki Kaisha, Kawasaki, JP;
Abstract
In a method and device for controlling the tracking in a playback mode in accordance with at least four pilot signals of different frequencies f1, f2, f3 and f4 which are sequentially recorded together with information signals on tracks of a recording medium in a predetermined cyclic sequence and which satisfy a relationship .vertline.f1-f2.vertline.:.vertline.f2-f3.vertline.:.vertline.f3-f4.vertli ne.=A:B:A, an extraction section extracts pilot signal components from reproduced signals obtained by playing back the recording medium. A reference signal supplying section supplies four reference signals which have the same relationship those of the four pilot signal frequencies f1, f2, f3 and f4 and a different cyclic sequence from that of the four pilot signals. A comparing and detecting section compares the extracted pilot signal components with the corresponding reference signals and detects differences between the two pilot signal components extracted from the right and left tracks adjacent to the reproduced track and the corresponding reference signals so as to obtain two difference frequency signal components which respectively have predetermined constant frequencies in any track. A detecting and generating section detects a level difference between the two difference frequency signal components and generates a tracking control signal having a polarity and level which correspond to a tracking error.