Abstract: A network system or terminal device utilizes a unique modulation scheme that enables the transmission of digital data over a wireless, cable or direct broadcast satellite TV channel without disturbing quality of television signals. A digital data stream of the network, for example, is transparently transmitted in the television channel in a superfluous sideband segment of the frequency spectrum using a technique, herein called vestigial quadrature modulation (VQM), that entails substituting the vestigial sideband of a conventional television signal with a sideband of a data-encoded signal, preferably being QAM-modulated. A sufficient portion of the television sideband spectrum displaced by the substituted data signal, e.g., to at least the 7.sup.th harmonic, is preserved for deriving sync information that is used both for clocking the digital data from the modulated data signal and for driving vertical and horizontal sync circuits of the television.

Abstract: A network terminal device utilizes a unique modulation scheme that enables the transmission of digital data over a wireless, cable or direct broadcast satellite TV channel without disturbing quality of television signals. A digital data stream of the network, for example, is transparently transmitted in the television channel in a superfluous sideband segment of the frequency spectrum using a technique, herein called vestigial quadrature modulation (VQM), that entails substituting the vestigial sideband of a conventional television signal with a sideband of a data-encoded signal, preferably being QAM-modulated. A sufficient portion of the television sideband spectrum displaced by the substituted data signal, e.g., to at least the 7.sup.th harmonic, is preserved for deriving sync information that is used both for clocking the digital data from the modulated data signal and for driving vertical and horizontal sync circuits of the television.

Abstract: A high index color encoding system (10) is provided for the purpose of receiving RGB video input from a personal computer or similar device and generating video signals in other formats for use by conventional video equipment. The color encoding system (10) includes operational circuitry (30) adapted to shape and modify the chrominance portions of the signals at a relatively high carrier frequency of four times the NTSC standard frequency with the lower NTSC output carrier being reconstituted by a doubly balanced mixer (266) component, thus substantially improving signal quality. The operational circuitry further includes synchronization generation circuitry (148), a Y, I, Q matrix (66) for creating luminance and chrominance components from RGB signals, an I, Q modulator (96) for producing high quality chrominance output and a dynamic aperture (246) for enhancing the rise slope of the luminance signal, among other components.