Hybrid Networks, Inc.

Other

William C Levan

An apparatus and method for subchannelizing a wide band data channel into plural narrow band subchannels. In particular, the apparatus and method functioning so as to subchannelize a standard television channel to permit data transfer over plural data channels of smaller bandwidth in a full-duplex, asymmetric hybrid network communication system.

Subchannelization scheme for use in a broadband communications system

An apparatus and method for channelizing wide band data at radio frequencies (RF) above that of a highest television channel a television headend is equipped to utilize or below 54MHz. In particular, the apparatus and method functioning so as to transmit 2MHz subchannels of data at roll-off band frequencies to at least one client in full-duplex, asymmetric hybrid network communication system.

Broadband communication system using TV channel roll-off spectrum

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. A receiver in a network terminal device utilizes an interface that includes a channel splitter and SAW filters in each of respective data and video channels for separately processing the video and digital data signals. The sync signal clocks data from the data channel and an integer multiple thereof drives the horizontal sync circuits of a television set.

Network device for handling digital data over a TV channel

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. A receiver in a network terminal device utilizes an interface that includes a channel splitter and SAW filters in each of respective data and video channels for separately processing the video and digital data signals. The sync signal clocks data from the data channel and an integer multiple thereof drives the horizontal sync circuits of a television set.

Network system for handling digital data over a TV channel

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. Various available video outputs to the system (10) are user selectable and user adjustable for compatibility with desired end use equipment and formats. The primary expected uses of the system are in graphics generation applications, utilization of conventional video equipment for computer video display and in memorialization of computer display sequences.

Growing community of inventors

San Jose, CA, United States of America

William C Levan