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:
May. 05, 1998
Filed:
Oct. 18, 1996
Jacques Michel, L'Hay les Roses, FR;
Dominique Trouche, Montgeron, FR;
Compagnie Generale d'Automatisme CGA-HBS, Bretigny sur Orge, FR;
Abstract
The magnetic code may include a run of b spoiled bits in a position that is locatable. The system consists in adding a check structure of k bits to the m-bit message in such a manner that the resulting n-bit word n=m+k is a cyclic redundancy code word generated by a generator polynomial G(x) of degree k that divides x.sup.n -1 without remainder in modulo-2 algebra. On reading, the system locates a packet of spoilt bits by detecting magnetic spoiling of the track which should normally be in the form of magnets of length l.sub.1 =l.+-.l/2 and l.sub.2 =2l.+-.l/2, with there being no runs of an odd number of successive magnets of length l.sub.1, given the bi-phase code used. A detected error is corrected by applying the relationship G(x) to the message as read after circular permutation has been applied thereto to move the missing bits to the end of the message.