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:
Apr. 08, 1986
Filed:
Dec. 07, 1983
Charles E Huffman, Plano, TX (US);
Richard L Majefski, Richardson, TX (US);
Rockwell International Corporation, El Segundo, CA (US);
Abstract
The present invention provides error checking for data dependent coding circuitry which checking is complicated by a considerable amount of circuitry which is activated only when the incoming data conforms to specific requirements (i.e., three or more consecutive logic zeros). Except for these occurrences, the output from the coding circuitry is straightforward representation of the nonreturn to zero input data. The present invention uses a straightforward detecting circuit to normally pass the data and a data compare circuit which compares the output of the detector with the output of the data dependent circuitry except for times when the specific condition of three consecutive logic zeros occurs. At that time, the data compare circuitry checks to make sure that both the code detector and the encoding circuit have detected the occurrence of this condition. Since the encoding circuitry has been working up to that time, it may be properly assumed that all of the circuitry is working properly and no error code is generated until either the straightforward data compare or the special condition detection fails to compare.