Telecommunication system for transmitting full motion video

• US 5,528,286 A
• Filed: 01/04/1994
• Issued: 06/18/1996
• Est. Priority Date: 08/20/1990
• Status: Expired due to Fees

• Current Assignee: Boysie M. Goolcharan
• Original Assignee: Christine Holland Trustee/Goolcharan Trust
• Inventors: Goolcharan, Boysie M.
• Primary Examiner(s): Chan, Jason
• Assistant Examiner(s): Woo, Stella L.
• Application Number:
  US08/177,704
• Time in Patent Office: 896 Days
• Field of Search: 348/17, 348/18, 348/19, 348/14, 348/15, 348/16
• US Class Current: 348/14.15
• CPC Class Codes: H04M 11/068 using time division multiplex techniques; integrated services digital networks H04Q11/0428
• CPC Class Codes: H04N 7/102 Circuits therefor, e.g. noise reducers, equalisers, amplifiers H04N7/108 takes precedence
• CPC Class Codes: H04N 7/108 the cable being constituted by a pair of wires
• CPC Class Codes: H04N 7/148 Interfacing a video terminal to a particular transmission medium, e.g. ISDN

Abstract

An improved telecommunication system is provided which allows the transmission of full motion color video, voice and data over a communications link formed of a twisted pair of wires of the type currently utilized only for voice and data communications. The signal is transmitted over the twisted pair link as a broadband signal up to a distance of six thousand feet. The twisted pair link exhibits a known impedance to the signal, depending upon the lengths of the twisted pairs of wires in the link. As the signal is received from the twisted pair link it is amplified and an impedance proportional to the impedance of the twisted pair link and vectorially opposite thereto is impressed thereon. A unity gain is achieved whereby the signal degrading effects of the impedance of the twisted pair link are reversed. This results in the accurate reproduction of a video signal over a link including significant lengths of conventional twisted pairs of telephone wires. Moreover, because the compensation for telephone line twisted pair impedance allows the accurate reproduction of a broadband signal, a plurality of different video, telephone and data signals can be multiplexed together and transmitted simultaneously over the same twisted pair link.

Claims

1. A telecommunication circuit for transmitting a broadband video signal of at least 4.5 megahertz band width over a link formed of a twisted pair of unloaded telephone wires having opposite ends, comprising:

symmetrical video transformer means coupled to one of said ends of said twisted pair link to receive and amplify said broadband video signal; and

correcting amplifier means coupled to said symmetrical video transformer means for impressing on said broadband video signal an impedance proportional to the impedance in said twisted pair link and in vector opposition thereto to thereby correct said broadband video signal for impedance degradation in said twisted pair link.