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.

Date of Patent:
Jun. 01, 1993

Filed:

Jan. 22, 1992
Applicant:
Inventor:

Per Lindholm, Stockholm, SE;

Assignee:

Shield Research in Sweden, Stockholm, SE;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04N / ;
U.S. Cl.
CPC ...
380-7 ; 380-6 ; 380 48 ; 380 10 ; 455-1 ;
Abstract

In a extraneous of signal method of preventing detection of signal information from raster scan signals in a plurality of consecutive line signals intended to form an image or partial images there is generated a random signal sequence, correlated with the information-carrying raster scan signals, but without information content, which is transmitted as protection for the raster scan signals. An apparatus for this purpose includes a generator (10,12) adapted for generating a random signal sequence synchronous with the raster scan signals, and a switching element (5) adapted to transmit the random signal sequence round the equipment containing the raster scan signals that are to be protected.


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