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:
Jun. 28, 1977
Filed:
Dec. 27, 1974
Stephen E Rice, Del Mar, CA (US);
Digital Development Corporation, San Diego, CA (US);
Abstract
A digital data encoding and decoding method and system is disclosed, with particular reference to magnetic records, in which bits are encoded in groups. Three out of four, two-bit combinations are encoded respectively by three patterns of transition placements under the rule that the two-bit group frame be divisible in only three sections having width of the read resolution R and the minimum spacing M between transitions is twice that value. The fourth bit combination is encoded under utilization of altogether four bits, using pattern combinations that extend over six sections R under the same constraint as to minimum spacing. Under otherwise similar conditions, the package density can be increased by 33% as compared with tri-period codes, and more than doubled as compared with frequency doubling or Manchester. The encoding scheme is generalized in that the selective extension of the encoding field for bit groups permits pattern encoding by a smaller number of permissible pattern combinations than seemingly necessary on basis of fixed bit group lengths.