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. 16, 1987
Filed:
Nov. 08, 1984
Masao Inaba, Tokyo, JP;
Kazuo Kashigi, Tokyo, JP;
NEC Corporation, , JP;
Abstract
A scrambling apparatus which scrambles a television signal prior to its transmission to prevent interception of the signal by means other than a counterpart descrambler apparatus. The television signal is scrambled by dividing each scan line (a scan line includes its leading sync portion) into first and second portions which are divided by an intermediate picture element. Each line is transmitted as follows: first the intermediate picture element is transmitted followed by the second scan line portion, followed by the first portion which begins with the sync signal and is terminated by retransmission of the intermediate picture element. The position of the intermediate picture element is randomly changed in each successive scan line so that reconstruction of the original television signal becomes exceedingly difficult. In the descrambler (receiver), a random address generator which includes a read only memory which contains the sequence of the position of the intermediate picture element in successive scan lines is used for receiving the scrambled television signal and descrambling the signal and restoring it to its original form for use in standard television receivers.