High speed data cable with impedance correction
First Claim
1. A cable for carrying one or more high speed differential digital data signals and one or more auxiliary signals between a source device and a sink device according to a cable specification, the cable comprising:
- a raw cable having one or more dual shielded cable elements, each dual shielded cable element comprising a shield and two shielded conductors for transmitting two polarities of a high speed differential digital data signal, an impedance of at least one dual shielded cable element being higher than a nominal impedance of the cable specified in the cable specification;
a first circuit carrier connecting the source device to the raw cable, the first circuit carrier including a shunt resistor, the shunt resistor being in parallel with the shielded conductors of said at least one dual shielded cable element; and
a second circuit carrier connecting the raw cable to the sink device, the second circuit carrier including a boost device for terminating the at least one dual shielded cable element and boosting the high speed differential digital data signal carried by said at least one dual shielded cable element, an output of the boost device being connected to the sink device.
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Accused Products
Abstract
A high speed video cable carries signals according to the High-Definition Multimedia Interface (HDMI) or DisplayPort standards, and includes a raw cable and may include a boost device. The raw cable includes coaxial lines of a characteristic cable impedance higher than the impedance implied in the standards. The correct impedance is observed at the sending end by shunt resistors mounted in the first cable connector. The resultant loss of signal may be made up with the boost device mounted in the connector at the other end of the cable in the case of a long cable. Increasing the cable impedance reduces the inherent loss of the raw cable thus permitting the use of low cost material such as tinned wires. Similar advantages are obtained regardless whether Shielded Twisted Pairs (STP) or coaxial lines are used.
78 Citations
21 Claims
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1. A cable for carrying one or more high speed differential digital data signals and one or more auxiliary signals between a source device and a sink device according to a cable specification, the cable comprising:
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a raw cable having one or more dual shielded cable elements, each dual shielded cable element comprising a shield and two shielded conductors for transmitting two polarities of a high speed differential digital data signal, an impedance of at least one dual shielded cable element being higher than a nominal impedance of the cable specified in the cable specification; a first circuit carrier connecting the source device to the raw cable, the first circuit carrier including a shunt resistor, the shunt resistor being in parallel with the shielded conductors of said at least one dual shielded cable element; and a second circuit carrier connecting the raw cable to the sink device, the second circuit carrier including a boost device for terminating the at least one dual shielded cable element and boosting the high speed differential digital data signal carried by said at least one dual shielded cable element, an output of the boost device being connected to the sink device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for transmitting a high speed differential digital data signal from a source device to a sink device over a digital video cable designed to meet a cable specification, the method comprising:
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coupling, in parallel with a shunt resistor, two polarities of the high speed differential digital data signal to an input of a raw cable, which has an impedance higher than a nominal impedance of the cable specified in the cable specification; coupling a differential output signal from an output of the raw cable to a boost device whose input matches the impedance of the raw cable; boosting the differential output signal to generate a boosted differential signal; and coupling the boosted differential signal to the sink device. - View Dependent Claims (19, 20, 21)
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Specification