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. 13, 1982
Filed:
Jun. 09, 1980
William D Little, Dallas, TX (US);
Other;
Abstract
A video transmission and receiving system provides continuous surveillance over a predetermined area in which video information is secured in such a manner that it cannot be intercepted by conventional television receivers. In the video transmission portion of the system, the pulse width of vertical synchronization pulses which occur during the vertical blanking interval are deliberately narrowed in duration, preferably equal in width to the equalization pulses which precede and follow the vertical pulse train, and which have an amplitude which is detectably greater than the amplitude of the horizontal synchronizing pulses and equalizing pulses. The narrow vertical pulses occur at the same frequency as the equalizing pulses and are separated from the horizontal synchronizing pulses by amplitude clipping instead of by waveform separation. The relatively high amplitude, relatively narrow width vertical synchronizing pulses are not detectable by the waveform integrating circuit of a conventional receiver since the interval between successive vertical synchronizing pulses is substantially greater than the vertical pulse duration.