Twisted pair communications line system

• US 20100045864A1
• Filed: 10/26/2009
• Published: 02/25/2010
• Est. Priority Date: 01/05/1994
• Status: Abandoned Application

• Current Assignee: Avocent Corporation (Vertiv Holdings Co.)
• Original Assignee: Avocent Corporation (Vertiv Holdings Co.)
• Inventors: Kirshtein, Philip M., Asprey, Robert R., Brown, Steven F., Stewart, Winston J.
• Application Number:
  US12/588,709
• Publication Number:
  US 20100045864A1
• Time in Patent Office: Days
• US Class Current: 348/503
• CPC Class Codes: H03F 1/22 by use of cascode coupling, i.e. earthed cathode or emitter stage followed by earthed grid or base stage respectively
• CPC Class Codes: H03F 1/34 Negative-feedback-circuit arrangements with or without positive feedback H03F1/02 - H03F1/30, H03F1/38 - H03F1/50, H03F3/50 take precedence ; for rejection of common mode signals H03F3/45479
• CPC Class Codes: H03F 2203/45168 A dif amp being used as input stage to one or more other non-differential stages
• CPC Class Codes: H03F 3/19 with semiconductor devices only
• CPC Class Codes: H03F 3/3432 with bipolar transistors
• CPC Class Codes: H03F 3/3437 with complementary transistors
• CPC Class Codes: H04N 5/148 Video amplifiers amplifiers in general H03F

Abstract

A transmission system for transmitting analog color video signals wherein a cable comprising multiple twisted pairs is employed, and certain of these pairs are coupled to carry selected color signals as a function of the delay provided by particular twist rates. In certain instances, selected signal delay devices are connected in circuit with certain twisted pairs. By such an arrangement, it has been found that relatively long distances between a computer and a monitor may be spanned by relatively low-cost, twisted pair cable commonly used for telephone communications.

Claims

1. A system for transmitting analog color video signals having color video components, comprising:

an interface to a cable having multiple twisted pairs, said pairs having varying twist rates relative to each other, said interface selectively coupling said pairs to carry selected ones of said color video components as a function of the varying relative twist rates.

2. A system according to claim 1, wherein the interface includes:

at least one transmitter to boost a signal strength of at least one of said color video signal components.

3. A system according to claim 2, wherein the interface further comprises:

at least two transmitters to boost signal strengths of corresponding ones of said color video signal components, said transmitters characterized by respectively differing gains.

4. A system according to claim 1, wherein the interface further comprises:

a cross switch to receive the color video signal components and apply the color video signal components to corresponding ones of the twisted pairs.

5. A system according to claim 1, wherein the cross switch further receives a sync signal of said analog color video signal and applies said sync signal to another of said twisted pairs.

6. A system according to claim 1, further including:

a computer to provide the analog color video signals having color video signal components.

7. A system according to claim 1, wherein the color video components include a red component and said interface selectively couples one of said twisted pairs having a lowest relative twist rate to the red component.

8. A system according to claim 1, wherein the color video components include a green component and said interface selectively couples one of said twisted pairs having a non-minimum relative twist rate to the green component.

9. A system according to claim 1, wherein the color video components include a blue component and said interface selectively couples one of said twisted pairs having a non-minimum relative twist rate to the blue component.

10. A system according to claim 1, wherein the color video components include a red, green, and blue component and said interface selectively couples a first of said twisted pairs having a lowest relative twist rate to the red component, a second of said twisted pairs having a next-lowest relative twist rate to the green component, and a third of said twisted pairs having a third-lowest relative twist rate to the blue component.

11. A system according to claim 1, wherein:

the color video components include a red, green, and blue component and a sync signal;

the cable includes four twisted pairs having respectively a first lowest relative twist rate, a second lowest relative twist rate, a third lowest relative twist rate, and a highest relative twist rate; and

said interface selectively couples the red component to said twisted pair having the first lowest relative twist rate, the green component to said twisted pair having the second lowest relative twist rate, the blue component to said twisted pair having the third lowest relative twist rate, and the sync signal to said twisted pair having the highest relative twist rate.

12. A system for receiving analog color video signals having color video components, comprising:

an interface to a cable having multiple twisted pairs, said pairs having varying twist rates relative to each other and carrying selected ones of said color video signal components, said interface imposing different relative signal delays on said color video components as a function of the varying relative twist rates.

13. A system according to claim 12, wherein the interface further includes:

a connector coupled to the twisted pairs, and

a cross switch coupled to the connector to selectively re-impose said signal delays to different ones of said color video components.

14-24. -24. (canceled)

25. A method of transmitting color video signals over a cable having a plurality of twisted pairs having varying twist rates, comprising the steps of:

ranking the twisted pairs according to their twist rates;

applying selected components of the color video signals to the twisted pairs in accordance with the ranking.

26. A method according to claim 25, wherein the step of applying includes the step of:

applying a red component of the color video signal to a twisted pair having a lower relative twist rate.

27. A method according to claim 25, wherein the step of applying includes the step of:

applying a green component of the color video signal to a twisted pair having a non-minimum relative twist rate.

28. A method according to claim 25, wherein the step of applying includes the step of:

applying a blue component of the color video signal to a twisted pair having a non-minimum relative twist rate.

29. A method according to claim 25, wherein the step of applying includes the step of:

applying a synchronization signal of the color video signal to a twisted pair having a highest relative twist rate.

30. A method according to claim 25, wherein the step of applying includes the step of:

applying components of the color video signal to selected twisted pairs having the lowest relative twist rates.

31. A method according to claim 25, wherein the step of applying includes the step of:

applying a red component of the color video signal to a twisted pair having a lower relative twist rate;

applying a green component of the color video signal to a twisted pair having a moderate relative twist rate;

applying a blue component of the color video signal to a twisted pair having a higher relative twist rate; and

applying a synchronization signal of the color video signal to a twisted pair having a highest relative twist rate.

32. A method of receiving color video signals over twisted pairs having non-uniform relative twist rates, comprising the steps of:

ranking the twisted pairs in accordance with their relative twist rates;

receiving components of the color video signals from different ones of the twisted pairs; and

delaying at least one component of the color video signals as a function of the ranking.

33-51. -51. (canceled)

52. A transmission system for coupling video color signals including red, green, and blue video components to corresponding twisted pair communication lines, including:

a circuit to impose a discrete signal delay on at least one of the video components as a function of a discrete first rate in a corresponding one of said twisted pair communication lines.