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:
Oct. 25, 1994
Filed:
Sep. 15, 1993
Kouji Kaniwa, Ibaraki, JP;
Hideo Nishijima, Ibaraki, JP;
Toshio Nakamoto, Ibaraki, JP;
Koichi Ono, Kanagawa, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A digital tracking device for use in a helical scan type magnetic recording and reproducing apparatus with an ATF system utilizing four-frequency pilot signals includes a sampling circuit which samples reproduced pilot signals with a frequency of a predetermined one of the four pilot signal frequencies, digital filter circuits for deriving aliasing signal components of the predetermined pilot signal produced by the sampling circuits, and a feedback circuit for feeding back a tracking error signal corresponding to signal levels of the aliasing signal components derived by the digital filter circuits to a magnetic tape drive system of the recording and reproducing apparatus.