Digital, frequency-translated, plural-channel, vestigial sideband television communication system
First Claim
1. A communication system comprising:
- first means, disposed at a transmitting station, coupled to receive intermediate frequency range vestigial sideband modulation information signals, for shifting said vestigial sideband modulated information signals to baseband frequency range;
second means, coupled to said first means, for converting said baseband-shifted vestigial sideband modulation information signals into prescribed transmission signals representative thereof and causing said prescribed transmission signals to be transmitted to a receiving station;
third means, disposed at said receiving station, for converting prescribed transmission signals transmitted from said second means into baseband-shifted vestigial sideband modulation information signals; and
fourth means, coupled to said third means, for shifting the baseband-shifted vestigial sideband modulation information signals obtained by said third means to intermediate frequency range vestigial sideband modulation information signals.
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Accused Products
Abstract
A television communication system distributes plural VSB digitally encoded TV channels via an optical transmission link to one or more distribution terminals. At the headend the frequency band of each of the VSB signals is shifted down to baseband and transmitted in digital format. At each station along the network, the digitized baseband VSB television signal is converted into analog format and then reshifted through an up-converter to its original IF band so as to be compatible with the television receiver circuitry of the subscribers served by the distribution station. Advantageously, the present invention may employ optical communication techniques for coupling the digitally encoded frequency-shifted VSB television signals between stations. To maintain signal strength and quality, repeater units may be located in the optical communication link. Each repeater converts an incoming optical signal to an electrical signal for amplification and then reconverts the improved electrical signal back into optical form for further transmission along the link.
237 Citations
36 Claims
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1. A communication system comprising:
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first means, disposed at a transmitting station, coupled to receive intermediate frequency range vestigial sideband modulation information signals, for shifting said vestigial sideband modulated information signals to baseband frequency range; second means, coupled to said first means, for converting said baseband-shifted vestigial sideband modulation information signals into prescribed transmission signals representative thereof and causing said prescribed transmission signals to be transmitted to a receiving station; third means, disposed at said receiving station, for converting prescribed transmission signals transmitted from said second means into baseband-shifted vestigial sideband modulation information signals; and fourth means, coupled to said third means, for shifting the baseband-shifted vestigial sideband modulation information signals obtained by said third means to intermediate frequency range vestigial sideband modulation information signals. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of conveying information from a transmitting station to a receiving station comprising the steps of:
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(1) at said transmitting station, shifting intermediate frequency range vestigial sideband modulation information signals to the baseband frequency range, (2) converting the baseband-shifted vestigial sideband modulation information signals into prescribed transmission signals representative thereof and transmitting said baseband-shifted signals to said receiving station, (3) at said receiving station, receiving the signals transmitted from said transmission station and converting the received signals into baseband-shifted vestigial sideband modulation information signals, and (4) shifting the baseband-shifted vestigial sideband modulation information signals to the intermediate frequency range, and thereby obtain the original vestigial sideband modulation information signals. - View Dependent Claims (9, 10, 11, 12)
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13. A communication system comprising:
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first means, disposed at a transmitting station and coupled to receive vestigial sideband modulation information signals at a first frequency range for shifting said vestigial sideband modulation information signals to a second frequency range lower than said first frequency range; second means, coupled to said first means, for converting said second frequency range-shifted vestigial sideband modulation information signals into prescribed transmission signals representative thereof and causing said prescribed transmission signals to be transmitted to a receiving station; third means, disposed at said receiving station, for converting prescribed transmission signals transmitted from said second means into second frequency range-shifted vestigial sideband modulation information signals; and fourth means, coupled to said third means, for shifting the second frequency range-shifted vestigial sideband modulation information signals obtained by said third means to first frequency range vestigial sideband modulation information signals. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method of conveying information from a transmitting station to a receiving station comprising the steps of:
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at said transmitting station, shifting vestigial sideband modulation information signals at a first frequency range to a second frequency range lower than said first frequency range; converting the second frequency range-shifted vestigial sideband modulation information signals into prescribed transmission signals representative thereof and transmitting said second frequency range-shifted signals to said receiving station; at said receiving station, receiving the signals transmitted from said transmission station and converting the received signals into second frequency range-shifted vestigial sideband modulation information signals; and shifting the second frequency range-shifted vestigial sideband modulation information signals to said first frequency range, and thereby obtain the original vestigial sideband modulation information signals. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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Specification