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:
Aug. 28, 1990
Filed:
Dec. 11, 1989
Akira Ideno, Tokyo, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
A method of scrambling a television signal is provided in which, during a horizontal blanking interval and during a vertical blanking interval, a video signal is compressed and a key signal containing information concerning the compression is superimposed on an audio signal in the horizontal blanking period. The method is characterized by superimposing a pseudo-key signal on an audio signal in the vertical blanking interval, making the key signal contain information concerning the position of a vertical blanking interval, and fixing a video signal in a predetermined number of horizontal scanning periods before a vertical synchronizing signal portion in the vertical blanking interval at a constant level while eliminating color bursts in a predetermined number of horizontal scanning periods before and after the vertical synchronizing signal portion in the vertical blanking interval. In this way, unauthorized users are prohibited from receiving the signal, and unauthorized access is made difficult.