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:
Sep. 04, 1984
Filed:
Jan. 15, 1982
Chao S Chi, Shrewsbury, MA (US);
Sperry Corporation, New York, NY (US);
Abstract
The Controlled Return to A.C. (CRA) magnetic recording and reproducing system applies a high frequency erase signal continuously to the write head except at the detents. At the detents polarity controlled interruptions of the high frequency erase signal are embedded therein. A positive interruption, a negative interruption and the absence of an interruption provides a ternary recording capability at the detent. The high frequency erase signal is controlled in phase to provide polarity coherent interruptions. A CRA cell includes two controlled interruptions providing a mapping of three binary digits into two CRA digits. The controlled interruption results in an opposite polarity pulse pair upon readback.