Rgb Systems, Inc.

Donald E Parreco

Raymond William Hall

A method and apparatus for automatic compensation of insertion loss in signals transmitted over conductors is presented. The present invention is particularly applicable to the transmission of signals over long lengths of CAT-5 or similar twisted-pair cables. A reference signal having a known form and strength (e.g. a pulse signal) is provided to each pair of conductors carrying a component of a signal from a transmitter to a receiver. The receiver includes adjustable gain amplifiers for each conductor pair over which a component of the signal is transmitted. The gains of the amplifiers are initially set at an initial level (e.g., their maximum gain) to allow detection of the reference signal. Once the reference signal is detected in a conductor pair, the amplifier gains are adjusted such that the level of the reference signal is restored approximately to its original form and strength.

Method and apparatus for automatic compensation of signal losses from transmission over conductors

A feedback circuit for restoration of DC in electrical signals is presented. A sample pulse representing a DC portion of an electrical signal is generated. The sample pulse triggers a sample and hold circuit to acquire the correct offset voltage in the electrical signal during this DC portion. The offset voltage feeds back through a summing node to the electrical signal thereby restoring the video signal to the desired DC voltage level with respect to ground.

Method and apparatus for DC restoration using feedback

A method and apparatus for automatic compensation of insertion loss in video signals transmitted over conductors is presented. The present invention is particularly applicable to the transmission of video over long lengths of CAT-5 or similar twisted-pair cables. A reference signal having a known form and strength (e.g. a pulse signal) is provided to each pair of conductors carrying a component of a video signal from a transmitter to a receiver. The receiver includes adjustable gain amplifiers for each conductor pair over which a component of the video signal is transmitted. The gains of the amplifiers are initially set at an initial level (e.g., their maximum gain) to allow detection of the reference signal. Once the reference signal is detected in a conductor pair, the amplifier gains are adjusted such that the level of the reference signal is restored approximately to its original form and strength.

Method and apparatus for automatic compensation of video signal losses from transmission over conductors

A feedback circuit for restoration of DC in video signals is presented. A sample pulse representing the back porch of an incoming video signal is generated from the horizontal sync signal. The sample pulse triggers a sample and hold circuit to acquire the correct offset voltage in the output signal during this back porch period. The offset voltage feeds back through a summing node upstream of either the circuit causing the offset or an input amplifier thereby restoring the video signal to the desired DC voltage level with respect to ground.

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Covina, CA, United States of America

Donald E Parreco