International Business Machines Corporation

International Business Corporation

Paul W Bond

Daniel Francis Casper

Francois Ibrahim Atallah

James D Rockrohr

Edward W Chencinski

Robert R Livolsi

Joseph M Hoke

Denise E Frey

Initialization of a bidirectional, self-timed parallel interface with capacitive coupling is provided. The self-timed interface includes master and slave nodes connected by a parallel bus comprising multiple AC differential wire pairs. The initialization includes automatically testing at least one wire pair of the multiple AC differential wire pairs for conductivity failure, wherein the testing is responsive to a link reset signal of a first frequency. The automatically testing includes employing a link test signal of a second frequency to test the at least one wire pair of the multiple AC differential wire pairs. The second frequency is a lower frequency than a third, operational signal frequency of the self-timed parallel interface, and the first frequency and the second frequency comprise different frequencies. An initialization testing and handshake approach between the master node and slave node is also provided.

Initialization of a bidirectional, self-timed parallel interface with automatic testing of AC differential wire pairs

An improved dual media transceiver for terminating an electrical transmission line wherein the transmission line may be a coaxial cable or a shielded twisted pair line. A length of shielded twisted pair line is provided for interconnection. A connector for receiving the transmission line is also provided, adapted to connect the twisted pair wires of the transmission line to a first end of the twisted pair wires of the interconnection line when the transmission line is twisted pair line, and, when the transmission line is coaxial cable, adapted to connect a center conductor of the transmission line to one of the twisted pair wires, at the first end, and the shield of the transmission line to the shield of the interconnection line at the first end. A center tap termination network is connected to the second end of the interconnection line, having a center tap port connected to the shield of the line. The twisted pair wires of the line are connected to the non-center tap ports of the termination network. The network has electrical elements selected and arranged so as to provide a balanced or unbalanced impedance, as the case may be, at substantially the matching value, to the interconnection line whether the transmission line is coaxial or twisted pair wires.

Remote connection of termination network

The initiation of the flyback interval of a variable format CRT display system is controlled by a frequency independent closed loop compensation circuit. The termination point of a sawtooth pulse, which is initiated at the start of the horizontal sync for the CRT display system, determines the point for the initiation of the flyback interval. The termination point of the sawtooth is compared with the center of the flyback interval. So long as the flyback pulse is perfectly centered on the termination point, the timing is proper. However, if it is off-centered, circuitry results in delaying or advancing the turning off of the horizontal yoke driver to modify the initiation of the flyback interval in a manner to compensate for the change in delay.

Cathode ray tube display horizontal deflection system with delay

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Hurley, NY, United States of America

Paul W Bond