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:
Mar. 27, 1979
Filed:
Aug. 11, 1977
Christopher Scientific Company, Anaheim, CA (US);
Abstract
Signal recording method and apparatus for efficiently correcting a bit error due to dropout occurred in recording an analog data into a digital data and reproducing the digital data is disclosed. The digital signal converted from the analog signal is divided into a plurality of groups to each of which a parity check bit is added. Record pattern is recorded on a record medium by a recording apparatus in accordance with a regular coding such as FM (frequency modulation) or MFM (modified frequency modulation) coding such that more than one bits in a group are not simultaneously influenced by the dropout, e.g. individual bits in a group are spaced from each other by several tracks. On reproducing, the coded digital signal is decoded into the original digital signal and the dropout is detected utilizing the nature of the regularity of the coding. The parity is checked for each of the groups. In this a single error in the group can be corrected and a double error is supplemented by holding a previous value, whereby the error due to the dropout is reduced.