Extended length differentially driven analog video link

An extended-in-length video communications system for transmitting computer analog video signals comprising:

• a source of computer analog video signals including at least one analog video signal and discrete horizontal sync and vertical sync signals,
• a video transmitter coupled to said source of computer analog video signals, said video transmitter comprising at least one signal amplifier having a signal input, and a first signal output and a second signal output, said analog video signal coupled to said signal input,
• a first twisted pair of conductors, with a first conductor of said twisted pair of conductors coupled at one end to said first signal output and a second conductor of said twisted pair of conductors coupled at one end to said second signal output, said first and second conductors being approximately equal in length,
• signal line compensating circuitry coupled to said amplifier for developing an optimized analog video signal optimized for a particular length of said first conductor, said optimized analog video signal applied to said first conductor from said first signal output,
• opposing video signal circuitry coupled to said amplifier for developing an opposing video signal opposite in polarity and approximately equal in amplitude to said optimized analog video signal, said opposing video signal applied to said second conductor from said second output, causing current flow in said second conductor approximately equal to and in an opposite direction to current flow in said first conductor, greatly reducing electromagnetic radiation from said twisted pair of conductors,
• a passive adapter coupled to an opposite end of said first conductor and said second conductor for developing a single ended computer analog video signal from said optimized analog video signal, and wherein said optimized analog video signal and said opposing video signal are balanced about a signal around potential at said adapter, said adapter further configured to provide a around reference potential for said transmitter at said adapter, eliminating need for a around reference conductor between said transmitter and said adapter.

A computer video signal communications system for selectively coupling sets of R, G, B computer color video signals from one of a plurality of computers to a separately located color monitor, said system comprising:

• a transmitter including:
• switching means for selectively providing a said set of said color video signals from a selected said computer, and
• a first signal format converter responsive to each said color signal of a said set of color signals from said switching means for converting a signal format of each said color signal from single ended format to a balanced format;
• a plurality of sets of twisted pair conductors, each set of said conductors having a first end and second end, with a said first end of each of said sets of conductors receiving a discrete color video signal from said transmitter;
• a receiver coupled to said second ends of said sets of said twisted pair conductors and including:
• a plurality of second signal format converters for converting a said balanced format of each said discrete color video signal from each said set of conductors from balanced to unbalanced format;
• and
• signal means responsive to unbalanced format signals from said receiver for coupling color video signals to a color video monitor.

A computer video signal communications system for selectively coupling a set of R, G, and B computer color video signals from one of a plurality of computers to a separately located color monitor, said system comprising:

• a transmitter including:
• switching means for selectively providing said set of R, G, and B computer color video signals from a selected said computer, and
• a first signal format converter responsive to each said R, G and B color video signal for converting a signal format of each said R, G and B color video signal from single ended format to a balanced format;
• a set of twisted pair conductors for each said balanced format R, G, and B color video signals, each said set of twisted pair conductors having a first end and a second end, with a said first end of each of said sets of twisted pair conductors receiving a discrete one of said balanced format R, G, and B color video signals from said transmitter;
• a receiver coupled to said second ends of said sets of twisted pair conductors and including:
• frequency compensation means for boosting a frequency response of each said R, G and B color video signal directly as a function of frequency;
• a plurality of second signal format converters for converting said balanced format of each said R, G and B color video signal from each said set of twisted pair conductors from balanced to unbalanced format;
• and
• signal means responsive to siad unbalanced format signals from said receiver for coupling said R, G and B color video signals to a color video monitor.

A computer color video signal communications system for selectively coupling sets of R, G, and B computer color video signals from one of a plurality of computers to a separately located color monitor, said system comprising:

• a transmitter including:
• switching means for selectively providing a set of said sets of R, G and B computer color video signals from a selected said computer, and
• a first signal format converter responsive to each said R, G and B computer color video signal of a said set of R, G, and B computer color video signals for converting a signal format of each said R, G and B computer color video signal from single ended format to a balanced format;
• a plurality of sets of twisted pair conductors, each set of twisted pair conductors having a first end and a second end, with a said first end of each said set of twisted pair conductors receiving a discrete one of said balanced format R, G and B computer color video signals of a said set from said transmitter;
• a receiver coupled to each said second end of each of said sets of said twisted pair conductors and including:
• frequency compensation means for boosting a frequency response of each of said R, G and B computer color video signals directly as a function of frequency;
• a plurality of second signal format converters for converting said balanced format of each said R, G and B computer color video signal from each said set of conductors from said balanced format to said unbalanced format;
• signal means responsive to unbalanced format signals from said receiver for coupling said R, G, and B computer color video signals to a color video monitor, and,
• a set of unbalanced twisted pair conductors coupled between said transmitter and said receiver, with one conductor of said conductors of said set of unbalanced twisted pair conductors carrying a horizontal synchronization signal and the other conductor of said unbalanced set of twisted pair conductors carrying a vertical synchronization signal, said horizontal synchronization signal and said vertical synchronization signal being with respect to a common reference within said receiver, said common reference being connected to at least one said second signal format converter, providing a return path through said twisted pair of conductors from said receiver to said transmitter.