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:
Oct. 18, 1983
Filed:
Aug. 18, 1980
U.S. Philips Corporation, New York, NY (US);
Abstract
'Method of coding data bits on a recording medium, arrangement for putting the method into effect and recording medium having an information structure.' The so-called Miller modulation has the disadvantage that a direct current is generated in the information channel. When this modulation method is used for magnetical or optical recording, the result is that the amplitude values and the zero crossings are deformed as these channels cannot transmit direct current. According to the invention, in order to obtain, a d.c. free modulation, the Miller modulation concept is modified such that sequences of data bits which, after coding, result in the introduction of a d.c. component are coded differently. It appears that, the frequency zero excepted, a good suppression of the response is obtained also in a fairly wide low-frequency portion of the spectrum. The invention further relates to an arrangement for putting the method into effect and to a recording medium, for example an optical disc, having an information structure which is coded by means of the d.c.-free coding.