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. 04, 1992
Filed:
Dec. 20, 1990
Hermann Gysel, San Jose, CA (US);
Synchronous Communications, Inc., San Jose, CA (US);
Abstract
A scrambled video digital transmission link comprising an amplitude modulator, a scrambler, an amplitude demodulator and frequency conversion apparatus for providing a scrambled video signal in a baseband format and a modified sound signal which includes video sync information which is used to restore the video signal for use in a subscriber's television set. The scrambled video signal in the baseband format and the modified sound signal are converted to a digital signal before transmission by a laser driven fiber optic transmission line to a hub station. In the hub station there is provided digital-to-analog signal converting apparatus, amplitude modulating apparatus and frequency conversion apparatus for recreating the scrambled video signal and modified sound signal generated in the head end station. The signals transmitted between the transmitter and the receiver may be in a digital pulse code modulation (PCM) format or in a format produced by digital modulation of an r.f. carrier, such as quarternary phase shift keying (QPSK) techniques.