Low impedance boosted high speed data cable
A high speed video cable carries signals according to the High-Definition Multimedia Interface (HDMI) or DisplayPort standards, and includes a raw cable and a boost device. The raw cable includes coaxial lines of a characteristic cable impedance lower than the impedance implied in the standards. The correct impedance is observed at the sending end by series resistors mounted in the first cable connector. The resultant loss of signal is made up with the boost device mounted in the connector at the other end of the cable.
1. A data cable for carrying at least a first data signal between a data source device and a data sink device, the data cable comprising:
a raw cable including at least a first cable element, the first cable element comprising at least a first conductor and a first conductive shield, the first cable element having a first cable element impedance lower than a data source device output impedance, wherein the first conductor is configured to carry at least a portion of the first data signal;
a first padding resistor electrically coupled between the data source device and the first conductor; and
a boost device coupling the first conductor with the data sink device, wherein a boost device input impedance matches the first cable element impedance and a boost device output impedance matches a data sink device input impedance.
2. The data cable of claim 1 , wherein a sum of a first padding resistor impedance and the first cable element impedance matches the data source device output impedance.
3. The data cable of claim 1 , wherein the boost device includes an amplifier to boost at least the first data signal.
4. The data cable of claim 1 , wherein the boost device includes an equalizer to equalize at least the first data signal.
5. The data cable of claim 1 , wherein the first data signal includes an analog signal.
6. The data cable of claim 1 , wherein the first data signal includes a digital signal.
7. The data cable of claim 1 , wherein the first data signal includes a video signal.
8. The data cable of claim 1 , further comprising:
a second conductor included in the first cable element;
a second padding resistor electrically coupling the data source device with the second conductor;
wherein the first data signal includes a differential signal, wherein the first and second conductors are configured to carry the differential signal; and
wherein the boost device includes a common mode rejection circuit adapted to remove a common mode component from the differential signal.
9. The data cable of claim 8 , wherein a combined impedance of the first and second padding resistors is substantially equal to a difference between the data source device output impedance and the first cable element impedance.
10. The data cable of claim 8 , wherein the first and second padding resistors have equal impedances.
11. The data cable of claim 8 , wherein the first cable element includes dual coaxial elements.
12. The data cable of claim 8 , wherein the first and second conductors are dual shielded.
13. The data cable of claim 8 , wherein the first cable element includes Shielded Twisted Pairs (STP).
14. The data cable of claim 8 , further comprising a first circuit carrier connecting the data source device to the raw cable, the first circuit carrier including the first and second padding resistors.
15. The data cable of claim 14 , further comprising a second circuit carrier including the boost device.
16. The data cable of claim 8 , wherein the data cable conforms with the High-Definition Multimedia Interface (HDMI) standard.
17. The data cable of claim 8 , wherein the data cable conforms with the DisplayPort standard.
18. The data cable of claim 8 , wherein the first data signal includes a Transition Minimized Differential Signaling (TMDS) signal.
19. The data cable of claim 8 , wherein the first data signal comprises a Main Line lane.
20. The data cable of claim 1 , further comprising at least a first auxiliary conductor configured to carry at least a first auxiliary signal including at least one of the following: a Consumer Electronics Control (CEC), a Serial Clock (SCL), a Serial Data (SDA), a Digital Data Channel (DDC), a CONFIG1, a CONFIG2, a Hot Plug Detect (HPD), a DisplayPort power (DP-PWR), a CEC ground connection, a power connection, and a ground connection.