High-quality twisted-pair transmission line system for high-resolution video
View Patent ↗A system comprising a first filter having an input and an output adapted to compensate for the characteristics of a first length of twisted-pair wire is disclosed. A first bypass path has an input and an output for bypassing the first filter. A second filter has an input and an output adapted to compensate for the characteristics of a first length of twisted-pair wire. A second bypass path has an input and an output for bypassing the first filter. A third filter has an input and an output adapted to compensate for the characteristics of a first length of twisted-pair wire. A third bypass path has an input and an output for bypassing the first filter. The three filters can be configured form a signal path or one or more filters removed from the signal path by switching in bypass paths.
1. A transmission line system, comprising a synchronization circuit for adding a synchronization pulse to a video signal, said synchronization pulse having amplitude at least fifty percent greater than said video signal, a transmission line having a loss and distortion characteristic for receiving the output of said synchronization circuit, and a filter network comprising a plurality of selectable filters configured to compensate said loss and distortion characteristic, said filters being selected to accommodate loss and distortion characteristics of lines of different length, a high-speed operational amplifier first clamp coupled to the output of said filters, the output of said operational amplifier first clamp being coupled to one end of a forward-biased semiconductor junction, the other end of said semiconductor junction being coupled to a second semiconductor clamp, said second semiconductor clamp having a second junction and exhibiting capacitance across said second junction, a third semiconductor clamp receiving the output of said second semiconductor clamp, said third semiconductor clamp being biased to cause a geometric increase in current flow through said third semiconductor clamp to regulate an undershoot condition at the output of said second semiconductor clamp.
2. A system as in claim 1 , wherein each of said selectable filters electrically defines a plurality of poles embodied in a plurality of resistor-capacitor networks.
3. A system as in claim 2 , wherein on of said selectable filters is adjustable to accommodate transmission lines of different length.
4. A system as in claim 2 , wherein a first of said filters accommodates for a first length of line, a second of said filters accommodates for said first of said filters and an additional length of line, and third of said filters accommodates for said first and second of said filters and a second additional length of line.
5. A system as in claim 4 , wherein one of said filters is a filter whose characteristics may be varied to accommodates additional transmission line length of different magnitude.