Note: Descriptions are shown in the official language in which they were submitted.
HIGH SPEED DATA CABLE INCLUDING A BOOST DEVICE FOR GENERATING A
DIFFERENTIAL SIGNAL
FIELD OF THE INVENTION
The present invention relates to the construction of high speed data cables,
which in some
embodiments may be boosted, and carry high speed signal lines.
BACKGROUND OF THE INVENTION
The distribution of television signals has increasingly become based on
digital methods and
digitally encoded forms of video and audio signals. At the same time, higher
resolution (high
definition TV) has become available in the market place, commensurate with
larger and higher
definition displays. To meet the requirement of interconnecting such high
definition displays with
digital signal sources such as Digital Versatile Disc (DVD) players and
receivers/decoders for digital
satellite and digital cable distribution of video material, a digital
interface standard has evolved,
known as the High-Definition Multimedia Interface (HDMI). A detailed
specification for HDMI can
be obtained from the "hdmi.org" website. The HDMI specification currently
available and used in
this application is HDMI specification version 1.4a dated March 04, 2010.
HDMI cables of various construction may be used for transmitting high speed
digital signals from
digital signal sources, including, but not limited to, the examples listed
above, to digital displays or
other equipment designed to receive signals according to the HDMI
specification.
A HDMI cable carries not only four high speed differential signals which are
shielded, but also a
number of lower speed signals, power and ground, the whole being further
shielded by an outer
braid. The resulting complex cable configuration with numerous wires, some of
which are indi-
vidually shielded, is expensive to manufacture and terminate.
Another standard for connecting video source to a video sink, is published as
the DisplayPort
standard by the Video Electronics Standards Association (VESA). The latest
DisplayPort specifi-
cation used in this application is DisplayPort v1.2, dated January 05, 2010
which is submitted in the
Information Disclosure Statement for this application. The DisplayPort
standard specifies a high
speed data cable that is intended primarily to be used between a computer and
its display monitor or
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a home-theater system. A cable meeting the DisplayPort standard is very
similar to an HDMI cable,
the main difference being in the respective physical connectors.
Therefore there is a need in the industry for developing an improved and lower
cost high speed
cable, which would avoid or mitigate the shortcomings of the prior art and
provides significant
economies at the same time.
Also there is a need in the industry for developing an improved and easier to
manufacture high
speed cable, which would avoid or mitigate the shortcomings of the prior art
and provides
significant economies at the same time.
SUMMARY OF THE INVENTION
Therefore there is an object of the invention to provide a high speed data
cable of an improved
construction, which would require fewer wires to carry required signals than
existing prior art
cables.
There is also an object of the invention to provide an improved boosted high
speed data cable using
a reduced number of wire elements, which would be more economical and have
superior properties
over existing prior art cables.
There is yet another object of the invention to provide an improved boosted
high speed data cable
with impedance correction, which would have superior properties over existing
prior art cables.
There is yet one more object of the invention to provide a low cost high speed
data cable, which
would have superior properties over existing prior art cables.
Therefore there is an object of the invention to provide an improved boosted
high speed data cable
using a reduced number of wire elements, which would be more economical and
have superior
properties over existing prior art cables.
According to one aspect of the invention, there is provided a cable for
carrying a high speed
differential digital data signal and two auxiliary signals between a source
device and a sink device
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according to a cable specification, the cable comprising: a raw cable,
comprising a split dual
shielded cable element, comprising a first shielded conductor enclosed in a
first individual shield,
and a second shielded conductor enclosed in a second shield, wherein the first
individual shield
electrically couples a first auxiliary signal from the source device to the
sink device, and the second
individual shield electrically couples a second auxiliary signal from the
source device to the sink
device, and wherein the shielded conductors are designated for carrying
respective polarities of the
high speed differential digital data signal; a single-ended to differential
converter (SDC) for
receiving one of the polarities from the raw cable and converting it to a
regenerated differential
signal, wherein: differential outputs of the SDC are electrically coupled with
the sink device; the
first shielded conductor is electrically coupled with an input of the SDC; and
the second shielded
conductor is electrically coupled with a termination element and not with the
SDC, wherein the
termination element is electrically coupled with a ground reference in the
sink device, wherein a
resistance of the termination element substantially matches an impedance of
the second shielded
conductor.
The cable further comprising a boost device, the boost device comprising the
SDC, the boost device
being configured for boosting the regenerated differential signal and
transmitting a boosted
regenerated differential signal to the sink device.
Conveniently, the termination resistor is contained in the boost device.
The cable further comprising a dual shielded cable element, comprising another
two shielded
conductors and a common shield, for carrying an additional high speed
differential digital data
signal over the another two shielded conductors, and an additional auxiliary
signal over the common
shield.
The cable further comprising another split dual shielded cable element,
comprising yet another two
shielded conductors enclosed in respective individual shields, for carrying
yet additional high speed
differential digital data signal over said yet another shielded conductors,
and two additional
auxiliary signals over the respective individual shields.
The cable of the embodiments of the invention is designed to satisfy the cable
specification, which
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is the High-Definition Multimedia Interface (HDMI) standard, and the raw cable
comprises only
two dual shielded cable elements, the split dual cable element, and the
another split dual shielded
cable element.
In the cable described above, wherein an output of said another split dual
shielded cable element is
configured to bypass the SDC.
In the cable designed to satisfy the HDMI standard, the high speed
differential digital data signals
are Transition Minimized Differential Signaling (TMDS) signals; and said
auxiliary signals
comprise Consumer Electronics Control (CEC), Serial Clock (SCL), Serial Data
(SDA), Hot Plug
Detect (HPD), Power and Ground signals.
In the cable of the embodiments of the invention, the boost device is
configured for boosting the
high speed differential digital data signals received from the dual shielded
cable element and from
said another split dual shielded cable element.
The cable further comprises: a first circuit carrier for connecting the source
device to the raw cable;
and a second circuit carrier for connecting the raw cable to the sink device,
and for mounting the
boost device thereon.
Conveniently, the termination resistor is mounted on the second circuit
carrier.
In the cable described above, said split dual shielded cable element comprises
two coaxial lines
whose individual shields are capacitively coupled to one another.
In the cable designed to satisfy the specification of High Definition
Multimedia Interface (HDMI)
standard, and the high speed differential digital data signal is a clock
signal.
In the cable described above, wherein an individual shield of the shielded
conductor, carrying said
one of the polarities of the differential digital data signal, is designated
for carrying an auxiliary
signal, which has substantially static properties.
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For example, the auxiliary signal, which has substantially static properties,
is a Hot Plug Detect
(HPD) signal according to High Definition Multimedia Interface (HDMI)
specification or
DisplayPort standard.
In the cable described above, wherein the individual shields of said another
split dual shielded cable
element may be designated for carrying respective auxiliary signals, which
have substantially static
properties.
For example, the auxiliary signals, which have substantially static
properties, may be Power and
Ground signals.
Conveniently, in the cable described above, wherein said split dual shielded
cable element
comprises two coaxial lines.
According to yet another aspect of the invention, a method for transmitting a
high speed differential
digital data signal and two auxiliary signals from a source device to a sink
device over a cable
having a raw cable, the method comprising: carrying a first and a second
polarity of the high speed
differential digital data signal from the source device to the sink device
over the raw cable,
comprising a split dual shielded cable element, having two shielded conductors
enclosed in
respective individual shields, each conductor carrying a respective polarity
of the high speed
differential digital data signal; carrying the two auxiliary signals in the
respective individual shields;
receiving the first polarity from the raw cable and converting it to a
regenerated differential signal;
receiving the second polarity from the raw cable and terminating it in a
termination element; and
transmitting the regenerated differential signal to the sink device.
The method further comprises designating an individual shield of the shielded
conductor, carrying
said one of the polarities of the differential digital data signal, for
carrying an auxiliary signal, which
has substantially static properties.
The method further comprises capacitively coupling two individual shields of
the two shielded
conductors.
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In the method described above, wherein the transmitting is performed according
to High Definition
Multimedia Interface (HDMI) specification or DisplayPort standard.
.. Thus, a lower cost boosted high speed data cable and a method of
transmitting digital signals over
the cable have been provided.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described, by way of example, with
reference to the
accompanying drawings in which:
Figure 1A shows a simplified boosted cable 10 to illustrate the principle of
transmitting a single-
ended signal and a differential signal over a shielded cable comprising a dual
shielded cable element
12, which is a Shielded Twisted Pair (STP), and a boost circuit 20;
Figure 1B shows a dual coaxial element 12B that may be used instead of the
dual shielded cable
element 12 of Fig. 1A;
Figure 2 shows a configuration 100 of a generic Boosted Digital Video Cable
102.j which may be
any of a number of types according to embodiments of the invention,
interconnecting a Video
Source Device (Tx) 104 and a Video Sink Device (Rx) 106;
Figure 3 shows a Basic Coax HDMI Cable 102.1 based on coax technology
according to a first
embodiment of the invention;
Figure 4 shows a Basic STP HDMI Cable 102.2 based on Shielded Twisted Pair
(STP) technology
according to a second embodiment of the invention;
Figure 5 shows a HEAC-Capable Coax HDMI Cable 102.3 based on coax technology
according to a
third embodiment of the invention;
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Figure 6 shows a HEAC-Capable STP HDMI Cable 102.4 based on Shielded Twisted
Pair (STP)
technology according to a fourth embodiment of the invention;
Figure 7 shows a Coax DisplayPort Cable 102.5 based on coax technology
according to a fifth
embodiment of the invention;
Figure 8 shows a STP DisplayPort Cable 102.6 based on Shielded Twisted Pair
(STP) technology
according to a sixth embodiment of the invention;
Figure 9 shows a three coax line cross sections, to illustrate a comparison
between exemplary design
choices, including a standard coax 902; a reduced-outer-diameter coax 904; and
an increased-core-
diameter coax 906;
Figure 10 shows a Low-Impedance (Low ZO) Coax HDMI Cable 102.10 which is
identical to the
Basic Coax HDMI Cable 102.1 of Fig. 3 except for a Low-Impedance Input Paddle
Board 114.10
which replaces the first Input Paddle Board 114.1;
Figure 11 shows a High-Impedance (High ZO) Coax HDMI Cable 102.11 which is
identical to the
Basic Coax HDMI Cable 102.1 of Fig. 3 except for a High-Impedance Input Paddle
Board 114.11
replacing the first Input Paddle Board 114.1;
Figure 12A shows a basic configuration 1200 of a split dual shielded cable
element 1202 including
two coax lines 1204 and 1206, analogous to the dual coaxial element 12B of
Fig. lb for carrying the
differential signal "D";
Figure 12B illustrates a First 8-Coax HDMI Cable 102.12 including a First 8-
Coax Input Paddle
Board 114.12, a First 8-Coax Raw Cable 108.12, and a First 8-Coax Output
Paddle Board 116.12, as
well as the Input and Output Connection Fields 212 and 214;
Figure 13A illustrates an expanded generic diagram 1300 of the generic Boosted
Digital Video
Cable 102.j of Fig. 2;
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Figure 13B illustrates a general diagram of a Second 8-Coax HDMI Cable 102.13,
which includes a
Second 8-Coax Input Paddle Board 114.13, a Second 8-Coax Raw Cable 108.13, and
a Second 8-
Coax Output Paddle Board 116.13;
Figure 14 shows a detailed diagram of the Second 8-Coax HDMI Cable 102.13 of
Fig. 13B,
including detailed diagrams of the Second 8-Coax Input Paddle Board 114.13,
the Second 8-Coax
Raw Cable 108.13, and the Second 8-Coax Output Paddle Board 116.13;
Figure 15 shows a configuration 1500 of a generic Unboosted Digital Video
Cable 1502.k which
may be any of a number of types described in the following figures, according
to embodiments of
the invention, interconnecting the Video Source Device (Tx) 104 and the Video
Sink Device (Rx)
106;
Figure 16 shows a Basic Unboosted Coax HDMI Cable 1502.1 based on coax
technology according
to an embodiment of the invention, including the Input Connection Field 212,
the first Input Paddle
Board 114.1, the first Raw Cable 108.1, the Output Connection Field 214, as
well as a first
Unboosted Output Paddle Board 1504.1;
Figure 17 shows a Basic Unboosted STP HDMI Cable 1502.2 based on Shielded
Twisted Pair
(STP) technology according to an embodiment of the invention, including the
Input Connection
Field 212, the second Input Paddle Board 114.2, the second Raw Cable 108.2,
the Output
Connection Field 214, as well as a second Unboosted Output Paddle Board
1504.2;
Figure 18 shows an Unboosted HEAC-Capable Coax HDMI Cable 1502.3 based on coax
technology according to an embodiment of the invention, including the HEAC-
capable Input
Connection Field 412, the third Input Paddle Board 114.3, the third Raw Cable
108.3, the HEAC-
= capable Output Connection Field 414, as well as a third Unboosted Output
Paddle Board 1504.3;
Figure 19 shows an Unboosted HEAC-Capable STP HDMI Cable 1502.4 based on
Shielded
Twisted Pair (STP) technology according to an embodiment of the invention,
including the HEAC-
capable Input Connection Field 212, the fourth Input Paddle Board 114.4, the
fourth Raw Cable
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108.4, the HEAC-capable Output Connection Field 214, as well as a fourth
Unboosted Output
Paddle Board 1504.4;
Figure 20 shows an Unboosted Coax DisplayPort Cable 1502.5 based on coax
technology according
to an embodiment of the invention, including the DisplayPort Input Connection
Field 612, the fifth
Input Paddle Board 114.5, the fifth Raw Cable 108.5, the DisplayPort Output
Connection Field 614,
as well as a fifth Unboosted Output Paddle Board 1504.5;
Figure 21 shows an Unboosted STP DisplayPort Cable 1502.6 based on Shielded
Twisted Pair
(STP) technology according to an embodiment of the invention, including the
DisplayPort Input
Connection Field 612, the sixth Input Paddle Board 114.6, the sixth Raw Cable
108.1, the
DisplayPort Output Connection Field 614, as well as a sixth Unboosted Output
Paddle Board
1504.6;
Figure 22 shows an Unboosted Low-Impedance Coax HDMI Cable 1502.10 which is
identical to
the Basic Unboosted Coax HDMI Cable 1502.1 of Fig. 16 except for the Low-
Impedance Input
Paddle Board 114.10 instead of the first Input Paddle Board 114.1, and
includes the Input
Connection Field 212, the first Raw Cable 108.1, the Output Connection Field
214, as well as a
Low-Impedance Unboosted Output Paddle Board 1504.10;
Figure 23 shows an Unboosted High-Impedance Coax HDMI Cable 1502.11 which is
identical to
the Basic Unboosted Coax HDMI Cable 1502.1 of Fig. 16 except for the High-
Impedance Input
Paddle Board 114.11 instead of the first Input Paddle Board 114.1, and
includes the Input
Connection Field 212, the first Raw Cable 108.1, the Output Connection Field
214, as well as a
High-Impedance Unboosted Output Paddle Board 1504.11; and
Figure 24 shows an Unboosted Low-Impedance 8-Coax HDMI Cable 1502.13,
including the Input
Connection Field 212, the Second 8-Coax Input Paddle Board 114.13, the Second
8-Coax Raw
Cable 108.13, the Output Connection Field 214, as well as a Low-Impedance
Unboosted Output
Paddle Board 1504.13.
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DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION
Embodiments of the present invention describe a boosted high speed cable
comprising shielded high
speed signal lines and carrying other signals of lower speed as well as power
and ground, in which
the shields of the shielded high speed signal lines are used in carrying the
lower speed signals and
power and ground.
The inherent characteristics and manufacturing imperfections of high-speed
differential signaling
cables such as may be used to carry HDMI signals have an adverse effect on the
high-speed signals
carried by the cable. To mitigate these effects, various boosted high speed
data cables have been
proposed by the industry. For example, in the previously filed US application
of the same assignee,
serial number 11/826,713 filed on July 18, 2007, a boost device is embedded in
the cable.
The inventors have discovered that the boost device may not only be used to
equalize and boost the
signal, as described in the US application serial number 11/826,713 cited
above, but may also be
used to advantage in other ways, specifically to allow the individual shields
of the differential high
speed signals to be used for carrying other signals.
In a cable of the prior art, the shields are all tied to ground in an effort
to reduce electro-magnetic
interference (EMI). In a cable according to any of the embodiments of the
invention, EMI shielding
is still provided, but instead of tying the shields of the high-speed HDMI
signals to ground, the
lower speed signals as well as power and ground, are sent over the shields.
Figure 1A shows a simplified boosted cable 10 to illustrate the principle of
transmitting a single-
ended signal and a differential signal over a shielded cable. The simplified
boosted cable 10
comprises a dual shielded cable element 12 which is a Shielded Twisted Pair
(STP) including a
single shield 14 enclosing first and second signal wires (two shielded
conductors) 16 and 18
respectively, and a boost circuit 20 having inputs i+ and i- and outputs o+
and o-. The inputs i+ and
i- of the boost circuit 20 are a differential input pair and the outputs o+
and o- of the boost circuit 20
are a differential output pair.
The simplified boosted cable 10 receives a single-ended signal "A" and a
differential signal "D"
comprising polarities D+i and D-i at the input of the simplified boosted cable
10, and is designed to
CA 2961317 2018-07-16
deliver these signals substantially undistorted at its output. The boost
circuit 20 includes an
equalizer circuit (EQ) and a differential amplifier (Amp) for equalizing and
boosting the differential
signal "D".
The signal wires 16 and 18 carry the differential signal "D", comprising
polarities D+i and D-i
respectively from the input of the simplified boosted cable 10 through the
dual shielded cable
element 12 to the inputs i+ and i- of the boost circuit 20. The outputs o+ and
o- of the boost circuit
20 deliver a processed differential signal comprising polarities D+o and D-o
to the output of the
simplified boosted cable 10, which represent the differential signal "D".
The single shield 14 carries a single-ended signal "A" directly from the input
of the simplified
boosted cable 10 to its output.
The processing functions of the boost circuit 20 include: receiving the
differential input signal;
removing any common mode component of the differential input signal;
equalizing the signal to
compensate for signal impairments introduced by the dual shielded cable
element 12; and outputting
a boosted version of the equalized differential signal "D".
To summarize, the differential signal is a high-speed data signal "D", which
may benefit from
equalization and boosting while the single-ended signal "A" may be a ground
signal, a power supply
signal, or any low speed signal which does not require equalization or
boosting.
Along the length of the STP raw cable 12, a small fraction of the single-ended
signal "A" is
unavoidably coupled as undesirable noise through distributed capacitances 22
and 24 into the signal
wires 16 and 18 respectively, thus affecting the differential signal "D".
Given that, by the
construction of the dual shielded cable element 12, the capacitances 22 and 24
are essentially equal,
the polarities D+i and D-i respectively are equally affected, and the coupled
noise manifests itself as
common mode noise.
At the receiving end of the dual shielded cable element 12, the boost circuit
20 receiving the
differential signal "D", provides sufficient common-mode rejection such that
the common mode
noise is not converted into a differential signal. The outputs o+ and o- of
the boost circuit 20, that
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produces a boosted signal, is then a clean differential signal which is
delivered at the output of the
simplified boosted cable 10.
Alternatively, as shown in Figure 1B, a dual coaxial element 12B may be used
instead of the dual
shielded cable element 12. The dual coaxial element 12B is comprised of two
coaxial lines 26 and
28 forming a coax pair 30 whose outer conductors (shields) are joined
together, the joined shields
providing the connection for the single-ended signal "A". The coaxial line 26
carries the polarity
D+i of the differential signal "D" on its inner conductor 32, while the
coaxial line 28 carries the
polarity D-i of the differential signal "D" on its inner conductor 34.
Coupling between the single-
ended signal "A" and the inner conductors 32 and 34 which are also referred to
as shielded
conductors, through distributed capacitances 36 and 38 respectively is
analogous to the case of the
dual shielded cable element 12, resulting in common mode noise only which is
rejected by the boost
circuit 20.
In the following figures, various boosted HDMI cable configurations are shown
which are
embodiments of the invention that are based on the cable elements described in
Figs. 1A and 1B.
Figure 2 shows a configuration 100 of a generic Boosted Digital Video Cable
102.j which may be
any of a number of types to be described below, connecting a Video Source
Device (Tx) 104 to a
Video Sink Device (Rx) 106. The Boosted Digital Video Cable 102.j comprises a
Raw Cable 108.j,
and Input and Output Connectors 110 and 112 respectively.
The Input Connector 110 connects the Raw Cable 108.j to the Video Source
Device (Tx) 104, and
comprises an Input Paddle Board 114.j for providing connectivity between
signals from the Video
Source Device (Tx) 104 and facilities (wires, shields) of the Raw Cable 108.j.
The Raw Cable 108.j includes dual shielded cable elements and optionally a
single coaxial line, for
carrying the video signals which are high speed differential data signals as
well as auxiliary signals
as defined by cable specifications, power and ground being included among the
auxiliary signals.
Alternatively, the raw cable may include dual shielded cable elements only,
i.e. excluding any other
wires between the video source device and the video sink device. A dual
shielded cable element
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may be a shielded twisted pair (STP), or a dual coaxial element comprising two
coaxial lines whose
shields are joined, each coaxial line enclosing one shielded conductor.
Various embodiments of the Raw Cable 108.j are described below, covering HDMI
and DisplayPort
specifications and using either coaxial or shielded twisted pair (STP)
technology.
The Output Connector 112 connects the Raw Cable 108 to the Video Sink Device
(Rx) 106, and
comprises an Output Paddle Board 116.j including a Cable Boost Device 118, for
providing
connectivity between the facilities (wires, shields) of the Raw Cable 108.j
and the Video Sink
Device (Rx) 106. The Cable Boost Device 118 is connected between some of the
wires of the cable
and the input of the Video Sink Device (Rx) 106. The Cable Boost Device 118
includes a number of
Boost Circuits 20, one Boost Circuit 20 for terminating the dual shielded
cable elements of the Raw
Cable 108 which carry the high speed differential digital data signals that
arrive from the Video
Source Device (Tx) 104 over the Raw Cable 108.
The Input Paddle Board 114.j and the Output Paddle Board 116.j constitute
first and second circuit
carriers which are conveniently constructed as small printed circuit boards
(PCB) and may be
configured to provide the mechanical support for connector contacts according
to the cable
specification, for example according to the HDMI or DisplayPort standards.
Figure 3 shows a Basic Coax HDMI Cable 102.1 based on coax technology,
including a circuit
carrier in the form of a first Input Paddle Board 114.1, a first Raw Cable
108.1, and a first Output
Paddle Board 116.1 according to an embodiment of the invention. The first Raw
Cable 108.1
includes a total of nine individual coaxial lines arranged as four dual
shielded cable elements, that is
coax pairs 202, 204, 206 and 208, and a single coaxial line 210. Each coax
pair 202 to 208
comprises two coaxial lines with inner signal wires labeled as "a" and "b",
and two shields which
are joined together such that the joined shields form a single conductive
path. Thus, each of the coax
pairs 202 to 208 provides three electrical connections, i.e. one differential
connection (wires "a" and
"b") and one single-ended connection (the joined shields), as described
earlier (see Fig. 1B). The
single coaxial line 210 provides only two conductive paths, the inner signal
wire "a" and the shield.
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The Cable Boost Device 118 is comprised within the first Output Paddle Board
116.1, and has high
speed differential signal inputs D2 (polarities D2+, D2-), D1 (D1+, D1-), DO
(DO+, DO-), and D3
( D3+, D3-) and corresponding boosted outputs C2 (polarities C2+, C2-), Cl
(C1+, Cl-), CO (CO+,
CO-), and C3 (C3+, C3-). In addition, the Cable Boost Device 118 has ground
and power inputs
(GND, +5V), and a programming input (Pgm). The programming input is used to
program
parameters of the Cable Boost Device 118 in manufacturing. In normal operation
this input is not
active, and is effectively grounded (connected to GND) through a low
resistance within the Cable
Boost Device 118.
HDMI signals may be classified as either high speed differential data signals
or auxiliary signals.
The high speed differential data signals include Transition Minimized
Differential Signaling
(TMDS) Data 0, TMDS Data 1, TMDS Data 2, and TMDS Clock. The auxiliary signals
are the
following single ended signals: Consumer Electronics Control (CEC), Serial
Clock (SCL), Serial
Data (SDA), Utility, Hot Plug Detect (HPD), and Serial Data (SDA). A +5V Power
and a Digital
Data Channel (DDC)/CEC Ground connection is also provided through the cable.
The +5V Power
and the DDC/CEC Ground connections are included in the auxiliary signals for
simplicity here.
The signals from the Video Source Device (Tx) 104 are connected to terminals
in an Input
Connection Field 212 of the Basic Coax HDMI Cable 102.1, and recovered at the
opposite end of
the cable with terminals of an Output Connection Field 214 for transmission to
the Video Sink
Device (Rx) 106. Standard HDMI signal names and corresponding terminal labels
of the Input and
Output Connection Fields 212 and 214 are listed in Table 1, which shows the
preferred connection
arrangement, or signal designations, for the Basic Coax HDMI Cable 102.1.
Referring to Fig. 3 and Table 1, each of the four HDMI high speed differential
data signals, TMDS
Data 0, TMDS Data 1, TMDS Data 2, and TMDS Clock, are routed through the Basic
Coax HDMI
Cable 102.1 as described in the following:
The TMDS Data 2 differential signal, comprising TMDS Data2+ and TMDS Data2-
is:
- connected from the Video Source Device (Tx) 104 to txD2+ and txD2- terminals
in the Input
Connection Field 212;
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- routed in the first Input Paddle Board 114.1 to the input of the raw
cable, namely the inner signal
wires "a" and "b" of the coax pair 202;
- routed through the inner signal wires "a" and "b" of the coax pair 202 of
the first Raw Cable
108.1;
- coupled from the end of the first Raw Cable 108.1 to D2+ and D2- inputs of
the Cable Boost
Device 118 in the first Output Paddle Board 116.1; and
- coupled from the C2+ and C2- outputs of the Cable Boost Device 118 to
rxD2+ and rxD2-
terminals in the Output Connection Field 214.
The other three HDMI high speed differential data signals (TMDS Data 0, TMDS
Data 1, and
TMDS Clock) are similarly connected, see Table 1.
The shields of the HDMI high speed data signals (TMDS Data0 Shield, TMDS Datal
Shield,
TMDS Data2 Shield, and TMDS Clock Shield), as well as the DDC/CEC Ground
signal from the
Video Source Device (Tx) 104 are connected to terminals txD0s, txD1s, txD2s,
txCKs, and txGnd
of the Input Connection Field 212, and tied to an input common ground node 216
in the first Input
Paddle Board 114.1 whence the input common ground node 216 is connected to the
shield of the
single coaxial line 210.
In the first Output Paddle Board 116.1, the shield of the single coaxial line
210 is connected to an
output common ground node 218 which is further connected to the ground (GND)
input of the
Cable Boost Device 118, and to shield and ground connections of the Video Sink
Device (Rx) 106,
namely terminals rxD0s, rxD1s, rxD2s, and rxGnd. The TMDS Clock Shield of the
Video Sink
Device (Rx) 106 is connected through a terminal rxCKs to the programming (Pgm)
input of the
Cable Boost Device 118, and so is indirectly grounded through the small
resistance within the Cable
Boost Device 118. This allows the Cable Boost Device 118 to be programmed from
the HDMI
connector after the boosted cable is assembled without requiring any
additional wire to access it.
Alternatively, the rxCKs terminal may be grounded directly at the output
common ground node 218
along with the other shield connections.
The remaining auxiliary signals (CEC, SCL, SDA, Utility, +5V Power, and HPD),
are connected in
the first Input Paddle Board 114.1 to terminals txCEC, txSCL, txSDA, txUt,
txPWR, and txHPD
CA 2961317 2018-07-16
respectively. In the first Output Paddle Board 116.1, they are connected to
terminals rxCEC, rxSCL,
rxSDA, rxUt, rxPWR, and rxHPD respectively. Compared to the HDMI high speed
data signals
which are boosted by the Boost Device 118, these auxiliary HDMI signals are at
a lower speed,
bypass the Cable Boost Device 118, and may be carried on the inner wires or
over the shields of the
coaxial lines as may be convenient. The "Utility" signal in this case is
unused. However if it is
necessary to include it, it may be carried on an additional inner wire or over
the shield of a coaxial
wire as may be convenient.
While four of the auxiliary signals CEC, SCL, +5V Power and HPD are carried
over the shields of
the coax pairs 202 to 208, another auxiliary signal (DDC/CEC Ground), to which
also the shields of
the TMDS signals are tied) is carried over the shield of single coaxial line
210, and yet another
auxiliary signal (SDA), is carried over the inner signal wire "a" of the
single coaxial line 210.
In the Basic Coax HDMI Cable 102.1, these remaining HDMI signals (except the
Utility signal) are
carried over the cable as follows:
CEC from the terminal txCEC, over the combined shields of the coax pair 202,
to the
terminal rxCEC;
SCL from the terminal txSCL, over the combined shields of the coax pair 204,
to the
terminal rxSCL;
SDA from the terminal txSDA, over the inner wire "a" of the coax 210, to the
terminal
rxSDA;
+5V Power from the terminal txPWR, over the combined shields of the coax pair
206, to the
terminal rxPWR; and
Hot Plug Detect from the terminal txHPD, over the combined shields of the coax
pair 208, to
the terminal rxHPD.
In the first Output Paddle Board 116.1 the +5V Power is also connected to the
power input (+5V) of
the Boost Device 218.
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Table 1: Preferred Signal Routing in Basic Coax HDMI Cable 102.1
HDMI Input Raw Boost Boost Output
Signal Name Connection Cable Device Device Connection
212 108.1 Input Output 214
TMDS Data2 Shield txD2s 210.shield --> --> rxD2s
TMDS Data2+ txD2+ 202.a D2+ C2+ rxD2+
TMDS Data2- txD2- 202.b D2- C2- rxD2-
TMDS Datal Shield txDls 210.shield --> --> rxD1s
TMDS Datal+ txD1+ 204.a D1+ C1+ rxD1+
TMDS Datal- txD1- 204.b D1- Cl- rxD1-
TMDS Data Shield txDOs 210.shield --> --> rxDOs
TMDS Data0+ txDO+ 206.a DO+ CO+ rxDO+
TMDS Data0- txDO- 206.b DO- CO- rxDO-
txCKs 210.shield - - -
TMDS Clock Shield
Pgm --> rxCKs
TMDS Clock+ txCK+ 208.a D3+ C3+ rxCK+
TMDS Clock- txCK- 208.b D3- C3- rxCK-
DDC/CEC Ground txGnd 210.shield GND --> rxGnd
CEC txCEC 202.shield --> --> rxCEC
SCL txSCL 204.shield --> --> rxSCL
SDA txSDA 210 --> --> rxSDA
Utility txUt n/c - - rxUt
+5V Power txPWR 206.shield +5V --> rxPWR
Hot Plug Detect txHPD 208.shield --> --> rxHPD
Figure 4 shows a Basic STP HDMI Cable 102.2 based on Shielded Twisted Pair
(STP) technology,
including a second Input Paddle Board 114.2, a second Raw Cable 108.2, and a
second Output
Paddle Board 116.2 according to another embodiment of the invention.
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The Input and Output Connection Fields 212 and 214, including the respective
terminals remain
unchanged from the Basic Coax HDMI Cable 102.2. The second Raw Cable 108.2
comprises five
Shielded Twisted Pairs (STPs) 302, 304, 306, 308, and 310, each comprising a
shield and two signal
wires "a" and "b" as described in Fig. 1A. The allocation of the standard HDMI
signals to
connections through the second Raw Cable 108.2 is provided by configurations
of the second Input
and Output Paddle Boards 114.2 and 116.2 respectively.
The STPs 302, 304, 306, 308, and 310 of the second Raw Cable 108.2 provide 15
(3 x 5) distinct
conductive paths, compared to the 14 paths (3 x 4 + 1) of the first Raw Cable
108.1. Hence an
additional path is available which is advantageously used in a modification of
the signal
assignments. This is illustrated in Fig. 4 as well as in Table 2 which lists
the preferred arrangement
for the Basic STP HDMI Cable 102.2.
Because of the additional line available in the second Raw Cable 108.2,
compared to the first Raw
Cable 108.1, it is possible to use a shield connection (a common node 312
connected to the shield of
the STP 308) to connect the shields of all high speed signals (DO, D1, D2, and
CK), and use a
separate shield connection (the shield of the STP 310) for the ground
connection.
The preferred assignments shown in Tables 1 and 2 are to some extent
arbitrary, and may be
adapted to best utilize the space on the paddle boards and the configurations
of the respective
connectors.
Table 2: Preferred Signal Routing in Basic STP HDMI Cable 102.2
HDMI Input Raw Boost Boost Output
Signal Name Connection Cable Device Device Connection
212 108.2 Input Output 214
TMDS Data2 Shield txD2s 308.shield --> --> rxD2s
TMDS Data2+ txD2+ 302.a D2+ C2+ rxD2+
TMDS Data2- txD2- 302.b D2- C2- rxD2-
TMDS Datal Shield txD1s 308.shield --> --> rxDls
TMDS Datal+ txD1+ 304.a D1+ C1+ rxD1+
TMDS Datal- txD1- 304.b Dl- Cl- rxD1-
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TMDS Data0 Shield txDOs 308.shield --> --> rxDOs
TMDS Data0+ txDO+ 306.a DO+ CO+ rxDO+
TMDS Data0- txDO- 306.b DO- CO- rxDO-
txCKs 308.shield -
TMDS Clock Shield
Pgm --> rxCKs
TMDS Clock+ txCK+ 308.a D3+ C3+ rxCK+
TMDS Clock- txCK- 308.b D3- C3- rxCK-
DDC/CEC Ground txGnd 310.shield GND --> rxGnd
CEC txCEC 306.shield --> --> rxCEC
SCL txSCL 310 --> --> rxSCL
SDA txSDA 310.b --> --> rxSDA
Utility txUt n/c - - rxUt
+5V Power txPWR 302.shield +5V --> rxPWR
Hot Plug Detect txHPD 304.shield --> --> rxHPD
In this embodiment of the invention, the raw cable includes STPs only, i.e.
excluding any other
wires between the video source device and the video sink device.
HEAC Capability
In a Supplement 2 to the HDMI specification version 1.4. dated June 05, 2009
cited above, a
"HDMI Ethernet and Audio Return Channel" (HEAC) is specified. The HEAC channel
is carried in
a HEAC-capable HDMI cable as a differential data signal, i.e. negative and
positive polarity signals
HEAC- and a HEAC+ respectively, which replace the Hot Plug Detect (HPD) signal
and the
previously unused "Utility" signal respectively of the standard HDMI signal
set. The HEAC channel
is a passive channel which does not require boosting by the Cable Boost Device
118. However, it
does require careful control of its impedance and should therefore be enclosed
in a shield, either by
running each polarity in a coaxial line, or both polarities over a shielded
twisted pair (STP).
Accordingly, only modified connectivity (adding the HEAC channel, with
controlled impedance
lines, replacing HPD and "Utility" signals) in the paddle boards and in the
raw cable are required to
convert the basic HDMI Cables (102.1 and 102.2) to accommodate the HEAC
channel.
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Figure 5 shows a HEAC-Capable Coax HDMI Cable 102.3 based on coax technology,
and capable
of carrying an HEAC channel: including a third Input Paddle Board 114.3, a
third Raw Cable 108.3,
and a third Output Paddle Board 116.3 according to yet another embodiment of
the invention.
The signals of the HEAC-capable HDMI signal set from the Video Source Device
(Tx) 104, are
connected to a HEAC-capable Input Connection Field 412 of the HEAC-Capable
Coax HDMI
Cable 102.3, and recovered at the opposite end of the cable with a HEAC-
capable Output
Connection Field 414 for transmission to the Video Sink Device (Rx) 106. The
modifications of the
HEAC-capable Input and Output Fields 412 and 414 relate to name changes
compared to the Input
and Output Fields 212 and 214, and reflect name changes of the terminals
concerned: txUt, rxUt,
txHPD, and rxHPD of the Input and Output Fields 212 and 214, become txHEAC-,
rxHEAC-,
txHEAC+, and rxHEAC+ of the HEAC-capable Input and Output Fields 412 and 414.
The third Raw Cable 108.3 comprises a total of ten individual coaxial lines
arranged in four dual
shielded cable elements, that is coax pairs 402, 404, 406, and 408, for
carrying high speed digital
data signals, and another dual shielded cable element, that is a coax pair
410, for carrying a
differential auxiliary signal. Each coax pair 402 to 410 includes two coaxial
lines with inner signal
wires labeled as "a" and "b", and two shields which are joined together such
that the joined shields
of each coax pair form a single conductive path. Thus, each of the coax pairs
402 to 410 provides
three electrical connections, i.e. one differential connection (wires "a" and
"b") and one single-
ended connection (the joined shields), as described earlier (see Fig. 1B).
The assignments of the HDMI signals to the available cable connections in the
third Input Paddle
Board 114.3 and the third Output Paddle Board 116.3 are similar compared to
the assignments used
in the first Input and Output Paddle Boards 114.1 and 116.1 respectively.
Unchanged connections
are those for the differential HDMI high-speed data channels TMDS D2, D1, DO,
and Clock,
incoming from the Video Source Device 104, which are connected through the
coax pairs 402, 404,
406, and 408 respectively to corresponding inputs of the Cable Boost Device
118.
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The differential HEAC channel is connected through the coax pair 410, and
bypasses the Cable
Boost Device 118. The shields of the coax pairs 402, 404, 406, 408, and 410
serve as conductors for
the HDMI signals CEC, SCL, +5V Power, SDA, and DDC/CEC Ground respectively.
Table 3: Preferred Signal Routing in HEAC-capable Coax HDMI Cable 102.3
HDMI Input Raw Boost Boost Output
Signal Name Connection Cable Device Device Connection
212 108.2 Input Output 214
TMDS Data2 Shield txD2s 410.shield --> --> rxD2s
TMDS Data2+ txD2+ 402.a D2+ C2+ rxD2+
TMDS Data2- txD2- 402.b D2- C2- rxD2-
TMDS Datal Shield txDls 410.shield --> --> rxDls
TMDS Datal-I- txD1+ 404.a D1+ C1+ rxD1+
TMDS Datal- txD1- 404.b D1- Cl- rxD1-
TMDS Data Shield txDOs 410.shield --> --> rxDOs
TMDS Data0+ txDO+ 406.a DO+ CO+ rxDO+
TMDS Data0- txDO- 406.b DO- CO- rxDO-
txCKs 410.shield - - -
TMDS Clock Shield
Pgm --> rxCKs
TMDS Clock+ txCK+ 408.a D3+ C3+ rxCK+
TMDS Clock- txCK- 408.b D3- C3- rxCK-
DDC/CEC Ground txGnd 410.shield GND --> rxGnd
CEC txCEC 402.shield --> --> rxCEC
SCL txSCL 404.shield --> --> rxSCL
SDA txSDA 408.shield --> --> rxSDA
HEAC- txHEAC+ 410 --> --> rxHEAC-
+5V Power txPWR 406.shield +5V --> rxPWR
HEAC+ txHEAC+ 410.b --> --> rxHEAC+
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The incoming shields of the HDMI high-speed data channels TMDS D2, D1, DO, and
the TMDS
Clock, are tied to the DDC/CEC Ground connection through the shield of the
coax pair 410 of the
cable, thus providing a connection to the outgoing shields of the HDMI high-
speed data channels
TMDS D2, D1, and DO. The outgoing shield of the TMDS Clock (rxCKs) is
connected to the
programming pin (Pgm) of the Cable Boost Device 118 as described above with
reference to the
Basic Coax HDMI Cable 102.1.
The preferred HDMI signal routing of the HEAC-Capable Coax HDMI Cable 102.3 is
listed in
Table 3.
Figure 6 shows a HEAC-Capable STP HDMI Cable 102.4, based on Shielded Twisted
Pair (STP)
technology and capable of carrying an HEAC channel, including a fourth Input
Paddle Board 114.4,
a fourth Raw Cable 108.4, and a fourth Output Paddle Board 116.4 according to
a fourth
embodiment of the invention.
The HEAC-capable Input and Output Connection Fields 412 and 414 of the HEAC-
Capable STP
HDMI Cable 102.4, including the respective terminals remain unchanged from the
HEAC-Capable
Coax HDMI Cable 102.3. The fourth Raw Cable 108.4 comprises five Shielded
Twisted Pairs
(STPs) 502, 504, 506, 508, and 510, each comprising a shield and two signal
wires "a" and "b" as
described in Fig. 1A. The allocation of the HDMI signals to connections
through the fourth Raw
Cable 108.4 is provided by configurations of the fourth Input and Output
Paddle Boards 114.4 and
116.4 respectively.
The STPs 502, 504, 506, 508, and 510 of the fourth Raw Cable 108.4 provide 15
(3 x 5) distinct
conductive paths, the same number as provided in the third Raw Cable 108.3.
Accordingly, an
analogous allocation of the individual signals to the Shielded Twisted Pairs
including their shields,
could be made. Similarly, part of the allocation scheme could also be
"borrowed" from the other
STP based embodiment (the Basic STP HDMI Cable 102.2) and suitably modified to
accommodate
the HEAC signal.
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A different connection allocation scheme is proposed here to illustrate the
considerable latitude
available in choosing configurations. The preferred assignments for the HEAC-
Capable STP HDMI
Cable 102.4 are illustrated in Fig. 6 as well as in Table 4.
As indicated earlier, the preferred assignments of signal leads in the cables
are shown in the Tables
1, 2, 3, and 4. These are to some extent arbitrary. The "+5V Power" and the
"DDC/CEC Ground"
connections are preferably carried on a shield; the HDMI high speed data
signals (TMDS DO, D1,
D2, and Clock) should always be carried on shielded conductors, i.e. the inner
conductors of coax
lines or the twisted signal wires of STPs, depending on wire type; and the
lower speed connections
(CEC, SCL, SDA, Utility, and HPD) may be carried on inner/ signal wires or
shields in an
arrangement that may be adapted to best utilize the space on the paddle boards
and the configuration
of the respective connectors.
The use of the TMDS Clock Shield connection on the receive side (rxCKs) to
access the
programming pin (Pgm) of the Cable Boost Device 118 is a convenience for
programming the
device in the fully assembled boosted HDMI cable. If this feature is not
required, the TMDS Clock
Shield should be grounded along with the other TDMS signal shields at both
ends of the cable.
Table 4: Preferred Signal Routing in HEAC-capable STP HDMI Cable 102.4
HDMI Input Raw Boost Boost Output
Signal Name Connection Cable Device Device Connection
212 108.2 Input Output 214
TMDS Data2 Shield txD2s 510.shield --> --> rxD2s
TMDS Data2+ txD2+ 502.a D2+ C2+ rxD2+
TMDS Data2- txD2- 502.b D2- C2- rxD2-
TMDS Datal Shield txDls 510.shield --> --> rxDls
TMDS Datal+ txD1+ 504.a D1+ C1+ rxD1+
TMDS Data1- txD1- 504.b D1- Cl- rxD1-
TMDS Data Shield txDOs 510.shield --> --> rxDOs
TMDS Data0+ txDO+ 506.a DO+ CO+ rxDO+
TMDS Data0- txDO- 506.b DO- CO- rxDO-
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txCKs 510.shield
TMDS Clock Shield
Pgm --> rxCKs
TMDS Clock+ txCK+ 508.a D3+ C3+ rxCK+
TMDS Clock- txCK- 508.b D3- C3- rxCK-
DDC/CEC Ground txGnd 510.shield GND --> rxGnd
CEC txCEC 506.shield --> --> rxCEC
SCL txSCL 508.shield --> --> rxSCL
SDA txSDA 504.shield --> --> rxSDA
HEAC- txHEAC--> 510 --> --> rxHEAC-
+5V Power txPWR 502.shield +5V --> rxPWR
HEAC+ txHEAC+ 510.b --> --> rxHEAC+
DisplayPort Cables
Figure 7 shows a Coax DisplayPort Cable 102.5 based on coax technology,
including a fifth Input
Paddle Board 114.5, a fifth Raw Cable 108.5, and a fifth Output Paddle Board
116.5 according to an
embodiment of the invention. The fifth Raw Cable 108.5 includes a total of ten
individual coaxial
lines arranged in five coax pairs 602, 604, 606, 608, and 610. Each coax pair
602 to 610 comprises
two coaxial lines with inner signal wires labeled as "a" and "b", and two
shields which are joined
together such that the joined shields form a single conductive path. Thus,
each of the coax pairs 602
to 608 provides three electrical connections, i.e. one differential connection
(wires "a" and "b") and
one single-ended connection (the joined shields), as described earlier (see
Fig. 1B).
The same Cable Boost Device 118 as in the boosted HDMI cables described above,
is comprised
within the fifth Output Paddle Board 116.5.
Standard DisplayPort signals from the Video Source Device (Tx) 104, are
connected to terminals in
a DisplayPort Input Connection Field 612 of the Coax DisplayPort Cable 102.5,
and recovered at
the opposite end of the cable at terminals of a DisplayPort Output Connection
Field 614 for
transmission to the Video Sink Device (Rx) 106. The DisplayPort signal names
and corresponding
terminal labels of the DisplayPort Input and Output Connection Fields 612 and
614 are listed in
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Table 5, which shows the preferred connection arrangement, or signal
allocation scheme, for the
Coax DisplayPort Cable 102.5.
Referring to Fig. 7 and Table 5, each of the four DisplayPort high speed
differential data lanes ML-
LO, ML-L1, ML-L2, and ML-L3, is routed through the Coax DisplayPort Cable
102.5 as described
in the following:
The Main Line Lane0 differential signal, comprising positive (p) and negative
(n) polarities is:
- connected from the Video Source Device (Tx) 104 to txML_LO+ and txML_LO-
terminals in the
.. DisplayPort Input Connection Field 612;
- routed in the fifth Input Paddle Board 114.5 to the inner signal wires
"a" and "b" of the coax pair
602;
- routed through the fifth Raw Cable 108.5 on the inner signal wires "a"
and "b" of the coax pair
602 of the fifth Raw Cable 108.5;
- coupled from the end of the fifth Raw Cable 108.5 to DO+ and DO- inputs of
the Cable Boost
Device 118 in the fifth Output Paddle Board 116.5; and
- coupled from the CO+ and CO- outputs of the Cable Boost Device 118 to
rxML_LO+ and
rxML_LO- terminals in the DisplayPort Output Connection Field 614.
The other three main-line differential data signals (Main Line Lanel, Lane2,
and Lane 3) are
similarly connected, see Table 5.
All ground connections of the incoming DisplayPort connector which are labeled
txGNDO,
txGND1, txGND2, txGND3, txGNDaux as well as the "Return" (txGNDpwr), i.e. the
power return
terminal, are tied together to an input common ground node 616 in the fifth
Input Paddle Board
114.5, and connected to the shield of the coax pair 604.
In the fifth Output Paddle Board 116.5, the shield of the coax pair 604 is
connected to an output
common ground node 618 which is also connected to the ground (GND) input of
the Cable Boost
Device 118, and to shield and ground connections of the Video Sink Device (Rx)
106, namely
terminals rxGNDO, rxGND1, rxGND2, rxGNDaux, and txGNDpwr. An exception is the
fourth
ground pin of the receive side which is connected through a terminal rxGND3 to
the programming
CA 2961317 2018-07-16
(Pgm) input of the Cable Boost Device 118, and so is only indirectly grounded.
This allows the
Cable Boost Device 118 to be programmed from the connector after the boosted
cable is assembled
without requiring any additional wire to access it. Alternatively, the rxGND3
terminal may also be
grounded at the output common ground node 618 along with the other ground
connections.
Other DisplayPort signals CONFIG1, CONFIG2, AUX Channel (p) and (n), Hot Plug,
and
DP_PWR, are respectively connected in the fifth Input Paddle Board 114.5 to
terminals
txCONFIG1, txCONFIG2, txAuxCh+ and txAuxCh-, txHPD, and txDP_PWR. In the fifth
Output
Paddle Board 116.5. they are respectively connected to terminals rxCONFIG1,
rxCONFIG2,
ncAuxCh+ and rxAuxCh-, rxHPD, and rxDP_PWR. Compared to the main line high
speed signals
which are boosted by the Boost Device 118, these other DisplayPort signals are
at a lower speed,
bypass the Cable Boost Device 118, and may be carried on the inner wires or
over the shields of the
coaxial lines as may be convenient. The AUX Channel signal however is of
moderately high speed
and is required to be carried in a controlled impedance wire, for which the
coax pair 610 is chosen
in this embodiment of the invention.
In the Coax DisplayPort Cable 102.5, the remaining signals are carried over
the cable as follows:
CONFIG1 from the terminal txCONFIG1, over the combined shields of the coax
pair 606, to
the terminal rxCONFIG1;
CONFIG2 from the terminal txCONFIG2, over the combined shields of the coax
pair 608, to
the terminal rxCONFIG2;
Hot Plug from the terminal txHPD, over the combined shields of the coax pair
610, to the
terminal rxHPD; and
DP_PWR from the terminal txDP_PWR, over the combined shields of the coax pair
602, to
the terminal rxDP_PWR.
In the fifth Output Paddle Board 116.5 the DP_PWR is also connected to the
power input (+5V) of
the Cable Boost Device 218. Even though the voltage of DP_PWR will be lower
than the HDMI
+5V Power, the same Cable Boost Device 218 may be designed or programmed to
run at both the
HDMI and the DisplayPort voltages. Alternatively, a DisplayPort specific
version of the Cable
Boost Device 218 may be developed.
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Table 5: Preferred Signal Routing in Coax DisplayPort Cable 102.5
DisplayPort Input Raw Boost Boost Output
Signal Name Connection Cable Device Device Connection
212 108.1 Input Output 214
Main Line Lane0 (p) txML_LO+ 602 DO+ CO+ rxML_LO+
Ground (pin 2) txGNDO 604.shield --> --> rxGNDO
Main Line Lane0 (n) txML_LO- 602.b DO- CO- rxML_LO-
Main Line Lane1 (p) txML_Ll+ 604 D1+ C1+ rxML_L 1+
Ground (pin 5) txGND1 604.shield --> --> rxGND1
Main Line Lanel (n) txML_Ll- 604.b D1- Cl- rxML_Ll-
Main Line Lane2 (p) txML_L2+ 606 D2+ C2+ rxML_L2+
Ground (pin 8) txGND2 604.shield --> --> rxGND2
Main Line Lane2 (n) txML_L2- 606.b D2- C2- rxML_L2-
Main Line Lane3 (p) txML_L3+ 608 D3+ C3+ rxML_L3+
Ground (pin 11) txGND3 604.shield
Pgm --> rxGND3
Main Line Lane (n) txML_L3- 608.b D3- C3- rxML_L3-
CONFIG1 txCONFIG1 606.shield --> --> rxCONFIG1
CONFIG2 txCONFIG2 608.shield --> --> rxCONFIG2
AUX Channel (p) txAuxCh+ 610 --> --> rxAuxCh+
Ground (pin 16) txGNDaux 604.shield --> --> rxGNDaux
AUX Channel (n) txAuxCh- 610.b --> --> rxAuxCh-
Hot Plug txHPD 610.shield --> --> rxHPD
Return txGNDpwr 604.shield GND --> rxGNDpwr
DP_PWR txDP_PWR 602.shield +5V --> rxDP_PWR
Figure 8 shows a STP DisplayPort Cable 102.6 based on Shielded Twisted Pair
(STP) technology,
including a sixth Input Paddle Board 114.6, a sixth Raw Cable 108.6, and a
sixth Output Paddle
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Board 116.6 according to an embodiment of the invention. The sixth Raw Cable
108.6 includes a
total of five STPs 702, 704, 706, 708, and 710, each comprising a shield and
two signal wires "a"
and "b" as described in Fig. 1A.
The allocation of the DisplayPort signals to connections through the sixth Raw
Cable 108.6 is
provided by configurations of the sixth Input and Output Paddle Boards 114.6
and 116.6
respectively, and is analogous to the allocation in the Coax DisplayPort Cable
102.5, Fig. 7. The
STP signal assignments are illustrated in Fig. 8 which is identical to Fig. 7
except for showing
Shielded Twisted Pairs (STPs) 702, 704, 706, 708, and 710 instead of coax
pairs 602-610. While the
sixth Input and Output Paddle Boards 114.6 and 116.6 have similar connectivity
to the
corresponding fifth Input and Output Paddle Boards 114.5 and 116.5, their
mechanical properties
would differ in order to accommodate the different termination geometries of
the STPs versus the
coax pairs on the paddle boards.
All auxiliary signals, CONFIG1, CONFIG2, Hot Plug, Ground and DP_PWR, may be
placed over
any shields of coaxial or STP lines as may be convenient or for an arrangement
that may be adapted
to best utilize the space on the paddle boards and the configuration of the
respective connectors.
Low Wire Count Summary
.. The number of wires in a boosted high speed digital video cable such as an
HDMI or DisplayPort
cable, has been reduced from fourteen or more in prior art cables to nine or
ten by using the shields
to individually carry active signals as well as power and ground. This
reduction is enabled by the
boost device which guarantees the removal of potentially harmful common mode
interference on the
high speed data lines. The reduction in the number of wires simplifies their
alignment for
termination in the connectors. The original high speed cables use a mix of
coaxial lines or shielded
twisted pairs and standard wires. The invention provides a reduction in the
construction cost of high
speed cables by the use of only a single type of wire, either coaxial or STP,
to carry all signals. This
significantly simplifies cable assembly and allows a single step termination
process, ultimately
reducing cost.
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Low Impedance Cables
In addition to the advantages obtained through the low wire count technique
described above, a
further cost advantage may be achieved by using coaxial lines or Shielded
Twisted Pairs (STP) of a
lower impedance than the nominal line impedance implied in the standards, for
carrying the high
speed data signals in any of the Boosted Digital Video Cables 102 described
here.
Figure 9 shows a three coax line cross sections, to illustrate a comparison
between exemplary design
choices, including a standard coax 902; a reduced-outer-diameter coax 904; and
an increased-core-
diameter coax 906. The standard coax 902 comprises an outer insulating sheath
902.a, a shield
902.b, an inner insulator 902.c, and a core wire (core) 902.d.
The reduced-outer-diameter coax 904 comprises an outer insulating sheath
904.a, a shield 904.b, an
inner insulator 904.c, and a core wire (core) 904.d. The increased-core-
diameter coax 906
comprises an outer insulating sheath 906.a, a shield 906.b, an inner insulator
906.c, and a core wire
(core) 906.d.
The characteristic impedance ZO of a coaxial line is determined by dimensions
of the cable, more
precisely, by the ratio of the diameter of the core wire to the inner diameter
of the shield, and by the
dielectric constant of the inner isolator material.
The core 902.d of the thin standard coax 902 with a characteristic impedance
of 50 ohms is an
American Wire Gauge (AWG) wire of about 78pm diameter, resulting in an overall
diameter of the
standard coax 902 of about 210pm.
.. By allowing the coax to have a lower, "non-standard" characteristic
impedance it is possible for
example, and without changing the insulator material, to either reduce the
outer diameter of the coax
without having to use a finer core wire, or to increase the core diameter
while keeping the outer
diameter constant.
The core 904.d of the reduced-outer-diameter coax 904 is the same wire gauge
as the core 902.d of
the standard coax 902, but the shield 904.c is shrunk such that a
characteristic impedance of 35
ohms is obtained for the reduced-outer-diameter coax 904. This results in an
overall diameter of the
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reduced-outer-diameter coax 902 of about 145pm, a savings of about 30%
compared to the standard
coax 902 with 50 ohm characteristic impedance.
If the outer diameter is not changed, a thicker core wire may be used. The
shield 906.b, hence the
overall diameter of the increased-core-diameter coax 906, corresponds to that
of the standard coax
902. However, the thickness of the core 906.d is increased such that a
characteristic impedance of
35 ohms is obtained for the increased-core-diameter coax 906, resulting in a
wire size of AWG 40
for the core 906.d of the increased-core-diameter coax 906. AWG 35 corresponds
to a wire
diameter of about 143pm, an almost 80% increase in thickness.
The inventors have considered the impact of deviating from the standard 50 ohm
coax for
implementing the HDMI and DisplayPort cables described above, that is the
Basic Coax HDMI
Cable 102.1, the HEAC-Capable Coax HDMI Cable 102.3, and the Coax DisplayPort
Cable 102.5,
as well as other boosted digital video cables. To recapitulate, the Video
Source Device 104
transmits high speed differential signals through coax pairs to the Cable
Boost Device 118 which
equalizes and boosts the signals before transmitting them to the Video Sink
Device 106.
The Video Source Device 104 is designed to transmit these high speed
differential signals over
cables presenting a characteristic impedance of 100 ohms differentially, that
is 2 times 50 ohms in
the case of dual coaxial lines (coax pairs). An input circuit in the Video
Sink Device 106 similarly
presents matching 100 ohms differential terminations to the cable.
In the case of the boosted cables with a reduced impedance coax, the Cable
Boost Device 118
provides a proper output circuit for transmission of the boosted signals to
the Video Sink Device
106. An input termination in the Cable Boost Device 118 can be tuned to
terminate a reduced
impedance cable with the correct impedance, for example 35 ohms, or 70 ohms
differentially.
The Video Source Device 104 is designed as a current source and would be able
to directly transmit
into any cable impedance; no undesired signal reflections would result as long
as the cable is
correctly terminated at the receiving end, that is at the Cable Boost Device
118. However,
compliance testing of HDMI and DisplayPort cables requires the cable to
present a nominal 100
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ohm differential impedance at source end for a unidirectional active cable and
both ends for a
passive cable.
Figure 10 shows a Low-Impedance (Low ZO) Coax HDMI Cable 102.10 which is
identical to the
Basic Coax HDMI Cable 102.1 of Fig. 3 except for a Low-Impedance Input Paddle
Board 114.10
which replaces the first Input Paddle Board 114.1. The Low-Impedance Input
Paddle Board 114.10
has the same connectivity as the first Input Paddle Board 114.1, except for
eight padding resistors
R1 to R8 which are inserted between the high speed signal terminals txD2+,
txD2-, txD1+, txD1-,
txD0+, txD02-, txCK+, and txCK- of the Input Connection Field 212, and the
inner signal wires "a"
and "b" of the corresponding coax pairs 202 to 208 of the first Raw Cable
108.1.
One pair of padding resistors is required to be inserted in series with each
of the inner signal wires
"a" and "b" of the TMDS signals. The resistance of each padding resistor is
derived such that the
combined resistance of two padding resistors in series with the inner signal
wires (the shielded
conductors) of each coax pair (dual shielded cable element) 202 to 208 is
equal to the difference
between the specified nominal cable impedance and the impedance of the coax
pair, for example a
100 ohm nominal impedance is achieved by using two coax lines of 35 ohm
impedance, each with
15 ohm padding resistors, as a coax pair.
The padding resistors R1 - R8 could be omitted without loss of functionality,
but they are provided
in order to meet the specified differential input impedance of 100 ohms for
the Low-Impedance
Coax HDMI Cable 102.10.
If the coax pairs 202 to 208 of the first Raw Cable 108.1 are made of low-
impedance coaxial lines,
such as the reduced-outer-diameter coax 904 or the increased-core-diameter
coax 906 which each
have an exemplary characteristic impedance of 35 ohms, the values of each of
the padding resistors
R1 to R8 should be 50 - 35 = 15 ohms, such that each coax pair, combined with
the padding
resistors, presents a 2 x 50 = 100 ohm impedance to the differential terminals
of the Input
Connection Field 212. In general, the resistance of each padding resistor R1
to R8 should be X
ohms, where X is equal to the difference between one half of the specified
nominal impedance (e.g.
100 Ohms for HDMI) and the actual characteristic impedance of the coax.
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Similarly, other coax based high speed video cables such as the HEAC-Capable
Coax HDMI Cable
102.3 (Fig. 5) and the Coax DisplayPort Cable 102.5 (Fig. 7) are easily
modified by the addition of
the padding resistors R1 to R8 on their respective input paddle boards, to
accommodate low-
impedance coax cables.
It is worth noting that signals other than the high speed differential data
signals, for example the
HEAC channel of HDMI and the AUX channel of DisplayPort, are not boosted by
the Cable Boost
Device 118. The coax pairs transporting these signals (coax pair 410 for HEAC,
and coax pair 610
for the AUX channel) can not be of the low-impedance type, but must be regular
50 ohm coaxes.
Alternatively, these signals may be carried over low-impedance type coax if
appropriate padding
resistors are provided at both the input and the output Paddle Boards. This
concept is not illustrated
here, but will be described further below (Fig. 15).
The same techniques for using reduced impedance coax cables also applies for
boosted HDMI and
DisplayPort cables that use Shielded Twisted Pairs (STP) for transmitting the
high speed differential
data signals. The characteristic impedance of STPs is determined by the ratio
of the insulated wire
diameter to the diameter of the bare wire, and the dielectric properties of
the insulation material.
Low-impedance STPs are easily made by reducing the thickness of the insulation
compared to the
diameter of the bare wire. This of course also affects the size of the shield.
A reduction in the
thickness of STP wire insulation by about 30% without changing the bare wire
thickness will reduce
the (differential) impedance of the STP from a nominal 100 ohms to 70 ohms.
Instead of reducing
the size of the STP cable in this way, it is also possible to maintain the
original overall size and
increase the bare wire thickness.
When a low impedance STP is employed in any of the boosted video cables based
on STP
technology, such as the Basic STP HDMI Cable 102.2 (Fig. 4), the HEAC-Capable
STP HDMI
Cable 102.4 (Fig. 6), and the STP DisplayPort Cable 102.6, the same
considerations as with the
coax based cables apply: the input circuit of the Cable Boost Device 118
should be programmed to
match the STP impedance, and the input paddle board should be modified to
include padding
resistors. Similar to the rule that applies in the coax case, the resistance
of each padding resistor R1
to R8 in the STP case should be Y ohms, where Y is equal to one half of the
difference between the
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specified nominal impedance (e.g. 100 Ohms for HDMI) and the actual
differential impedance of
the STP.
The lowering of the characteristic impedance in coax or STP based cables which
include boost
devices has a number of advantages which may be exploited, either to reduce
the size of the cable
for material savings, improved flexibility, etc., or to increase the wire size
without reducing the
overall size of the cable for improved handling, and lower material cost. Note
that thicker wire may
actually cost less to produce than very fine wire.
Based on the Basic Coax HDMI Cable 102.1, a further number of inventive
concepts are disclosed
which may be used separately or in combinations to improve the economic value
of high speed data
cables, including:
- a boosted video cable, comprising a raw cable with higher impedance (Fig.
11);
- reducing the wire count by splitting coax pairs into individual coax lines
(Fig. 12A);
- reducing the wire count by carrying a high speed signal single ended (Fig.
12B);
- reducing the wire count by carrying a signal on the cable's braid (Fig.
13B and Fig. 14);
- providing previously described advantages in a cable without a boost
device (Figs. 15
to Fig. 24).
Boosted Video Cable with High Impedance Raw Cable
In some cases, there may be an advantage to manufacture cables with coaxial
lines of a higher
impedance than the nominal impedance of 50 ohms. Similarly, STPs of a higher
differential
impedance than the nominal impedance of 100 ohms may be advantageous. These
may be valuable,
for example to reduce loss in the case of a tinned copper conductor material,
by increasing the size
of the insulation which increases the impedance of the raw cable.
As mentioned already, the Video Source Device 104 is designed to transmit high
speed differential
signals over cables presenting a characteristic impedance of 100 ohms
differentially, that is 2 times
50 ohms in the case of dual coaxial lines (coax pairs), or over STPs of
nominal 100 ohms
impedance.
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The Cable Boost Device 118 provides a proper impedance output circuit for
transmission of the
boosted signals to the Video Sink Device 106. An input termination in the
Cable Boost Device 118
can be tuned to terminate an increased impedance cable with the correct raw-
cable impedance, for
example over the range of 60 ohms to 150 ohms differentially.
However, compliance testing of HDMI and DisplayPort cables requires the cable
to present a
nominal 100 ohm differential impedance at the source end of a unidirectional
active cable, such as a
boosted cable.
Figure 11 shows a High-Impedance (High ZO) Coax HDMI Cable 102.11 which is
identical to the
Basic Coax HDMI Cable 102.1 of Fig. 3 except for a High-Impedance Input Paddle
Board 114.11
replacing the first Input Paddle Board 114.1. The High-Impedance Input Paddle
Board 114.11 has
the same connectivity as the first Input Paddle Board 114.1, except for the
addition of four shunt
resistors R9 to R12 which are connected between the high speed signal
terminals of respectively the
pairs (txD2+, txD2-), (0(131+, txD1-), (txD0+, txD02-), and (txCK+, and txCK-)
of the Input
Connection Field 212.
The resistance of each shunt resistor is derived such that the combined
resistance of each padding
resistor R9 to R12 in parallel with the impedance of the corresponding coax
pair (dual shielded
cable element) 202 to 208 is equal to the specified nominal cable impedance.
For example, where
the cable is comprised of coax pairs, each individual coax line having an
impedance of ZO = 75
ohms, the 100 ohm nominal differential impedance at the cable input may be
achieved with 300
ohm shunt resistors as illustrated in Fig. 11. In general, the value of each
shunt resistor Rx (R9 to
R12) may be calculated as:
Rx = 1 / ((1 / Zn) - (1 / (2 * ZO))),
where ZO is the impedance of the individual coax line, and Zn is the desired
differential input
impedance of the cable, that is, the inverse of the resistance of the shunt
resistor is equal to the
difference between the inverse of the nominal impedance Zn and the inverse of
the differential
impedance of the coax pair which is twice the impedance ZO of one coaxial
line.
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The shunt resistors R9 to R12 could be omitted without loss of functionality,
but they are provided
in order to meet the specified differential input impedance of 100 ohms for
the High-Impedance
Coax HDMI Cable 102.11.
Similarly, other coax based high speed video cables such as the HEAC-Capable
Coax HDMI Cable
102.3 (Fig. 5) and the Coax DisplayPort Cable 102.5 (Fig. 7) are easily
modified by the addition of
the shunt resistors R9 to R12, placed across respective high speed
differential signals on their
respective input paddle boards, to accommodate higher impedance coax cables.
It is worth noting that signals other than the high speed differential data
signals, for example the
HEAC channel of HDMI and the AUX channel of DisplayPort, are not boosted by
the Cable Boost
Device 118. The coax pairs transporting these signals (the coax pair 410 for
HEAC, and the coax
pair 610 for the AUX channel) can not be of the high-impedance type, but must
be regular 50 ohm
coaxes. Alternatively, these signals may be carried over high-impedance type
coax if appropriate
shunt resistors are provided at both the input and the output Paddle Boards.
This concept is not
illustrated here.
The same techniques for using increased impedance coax cables may also be
applied for boosted
HDMI and DisplayPort cables that use Shielded Twisted Pairs (STP) for
transmitting the high speed
differential data signals. The characteristic impedance of STPs is determined
by the ratio of the
insulated wire diameter to the diameter of the bare wire, and the dielectric
properties of the
insulation material.
High-impedance STPs are easily made by increasing the thickness of the
insulation compared to the
diameter of the bare wire. This of course also affects the size of the shield.
An increase in the
thickness of STP wire insulation by about 30% without changing the bare wire
thickness will
increase the differential impedance of the STP from a nominal 100 ohms to 150
ohms. Instead of
increasing the size of the STP cable in this way, it is also possible to
maintain the original overall
size and decrease the bare wire thickness of the twisted wires.
When a high impedance STP is employed in any of the boosted video cables based
on STP
technology, such as the Basic STP HDMI Cable 102.2 (Fig. 4), the HEAC-Capable
STP HDMI
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Cable 102.4 (Fig. 6), and the STP DisplayPort Cable 102.6, the same
considerations as with the
coax based cables apply: the input circuit of the Cable Boost Device 118
should be programmed to
match the STP impedance, and the respective input paddle boards should be
modified to include the
shunt resistors R9 to R12.
As illustrated in Figs. 10 and 11, a corrected effective impedance of the
cable, or measured cable
input impedance, which is substantially equal to the nominal impedance of the
digital video cable
specified in the cable specification, is achieved using resistor networks of
series or shunt resistors
respectively, and thus permits the use of low or high impedance raw cables
respectively.
Additional Reduced Wire Count Techniques
For economic reasons, it is desirable to reduce the number of coaxial lines
while still carrying all
required signals. The technique of carrying a low speed signal in the joined
shields of a dual
shielded cable element has been described above, for example using the joined
shields of the dual
shielded cable element 202 (Fig. 3) for carrying the CEC signal. This has
resulted in a design in
which nine coaxial lines (four dual shielded cable elements and a single coax
line) carry fourteen
HDMI signals.
In order to further reduce the number of coaxial lines to eight, and still
carry fourteen HDMI
signals, the inventors propose to split two of the dual shielded cable element
into split dual shielded
cable elements.
A split dual shielded cable element comprises two coax lines whose shields are
not galvanically
joined, but only coupled to each other through a capacitor providing AC
coupling. At the same time
each shield provides an independent capability of carrying a low speed signal.
Figure 12A shows a basic configuration 1200 of a split dual shielded cable
element 1202 including
two coax lines 1204 and 1206, analogous to the dual coaxial element 12B of
Fig. lb for carrying the
differential signal "D" which includes the polarities D+i and D-i. But instead
of joining the shields
of the two coax lines 1204 and 1206 galvanically, they are only joined in a
high-frequency coupling
or capacitive coupling through a coupling capacitor Cs, connected to the
shields at the inputs of the
two coax lines 1204 and 1206. This allows two independent single-ended signals
Al and A2 to be
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carried on the respective shields while still preserving the transmission
characteristics of the dual
shielded cable element with respect to the differential data signal "D" which
is a high-speed signal.
In the split dual shielded cable element 1202, crosstalk from the shields to
the inner conductors
carrying the differential signal is no longer automatically cancelled, and it
is necessary to carefully
select which connections should be carried on the shields. Preferably only
static signals such as
power and ground should be carried, or the inner conductor(s) may be used to
carry the clock signal
which is of lower speed than the other high speed signals, and which can be
recovered more easily
even if it is impacted by some cross talk.
On one hand, the capacitance of the coupling capacitor Cs is chosen to be high
enough to preserve
transmission characteristics of the dual shielded cable element with respect
of the high speed
differential signal, including providing A/C coupling between the individual
shields to be
substantially the same as a galvanic connection between a common shield of a
dual shielded
element. On the other hand, the capacitance of the coupling capacitor Cs is
chosen to be low enough
not to cause cross talk between low speed auxiliary signals.
The differential signal from the output of the split dual shielded cable
element 1202 is coupled to
the boost circuit, while the single-ended signals (Al) and (A2) are simply
forwarded. A second
(optional) coupling capacitor Co may be used to couple the shields of the coax
lines 1204 and 1206
to one another at the cable output. The value of the coupling capacitor Cs
(and Co if used) is
preferably of the order of 1 nF, to provide an effective AC-short between the
shields thus providing
substantially the same coupling (with respect to high speed signals) as the
galvanic connection of
Fig. 1B. This has the effect of adding the (single-ended) impedances of the
two coax lines to
provide their sum as a differential impedance. At the same time, the coupling
capacitor Cs provides
negligible coupling between the single-ended signals Al and A2 which may be DC
signals such as
power and ground, or low-speed, quasi-static signals such as the HDMI HPD and
CEC signals.
Figure 12B illustrates a First 8-Coax HDMI Cable 102.12 including a First 8-
Coax Input Paddle
Board 114.12, a First 8-Coax Raw Cable 108.12, and a First 8-Coax Output
Paddle Board 116.12, as
well as the Input and Output Connection Fields 212 and 214.
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The First 8-Coax HDMI Cable 102.12 incorporates two split dual shielded cable
elements 1208 and
1210 each comprising two coax lines (1208A and 1208B, and 1210A and 1210B
respectively) in the
First 8-Coax Raw Cable 108.12 and corresponding coupling capacitors Cl and C2
mounted on the
First 8-Coax Input Paddle Board 114.12.
The First 8-Coax Raw Cable 108.12 further includes two dual shielded cable
elements, that is coax
pairs 1212 and 1214.
The First 8-Coax Input and Output Paddle Boards 114.12 and 116.12 respectively
are arranged to
provide connectivity between the Input and Output Connection Fields 212 and
the First 8-Coax Raw
Cable 108.12. Where the First 8-Coax Raw Cable 108.12 is constructed with low-
impedance coax
lines, the First 8-Coax Input Paddle Board 114.12 may include padding
resistors R13 to R20,
analogous to the padding resistors R1 to R8 of Fig. 10, each padding resistor
connected in series
between a TMDS signal or clock terminal of the Input Connection Field 212 and
one of the eight
shielded conductors of the dual shielded cable elements or the split dual
shielded cable elements.
The resistance value of each of the padding resistors R13 to R20 is determined
as the difference
between one half of the nominal differential impedance of the First 8-Coax
HDMI Cable 102.12,
that is 100 ohms for each of the high speed differential data signals, and the
impedance of each of
the coaxial lines. For example, when 35-ohm coax lines are used in the First 8-
Coax Raw Cable
108.12, each padding resistor (R13 to R20) should have a resistance of 15
ohms, so that the nominal
differential HDMI impedance of 100 ohms is present at the Input Connection
Field 212.
The padding resistors R13 to R20 are omitted when 50-ohm coax lines are used.
Alternatively (not
shown in Fig. 12B), shunt resistors analogous to the shunt resistors R9 to R12
of Fig. 11 would be
used if coax lines of a higher impedance than 50 ohms are used in the First 8-
Coax Raw Cable
108.12.
A preferred signal routing in the First 8-Coax HDMI Cable 102.12 is
illustrated in Fig. 12B and
shown in Table 6 below. The differential TMDS Data signals and the TMDS Clock
signal are
coupled through the padding resistors R13 to R20 to the inner (shielded)
conductors of the eight
coax lines.
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The galvanically joined shields of the dual shielded cable elements 1212 and
1214 are connected in
the paddle boards to carry respectively the low-speed HDMI signals SCL and
SDA.
The shields of the four coax lines 1208A, 1208B, 1210A, and 1210B of the two
split dual shielded
cable elements 1208 and 1210 are connected to carry respectively four static,
or predominantly
static low speed signals having have substantially static properties, namely:
DDC/CEC Ground;
+5V Power; CEC; and HPD. The proposed signal assignments of the First 8-Coax
HDMI Cable
102.12, shown in Fig. 12B and in Table 6 below are merely examples, and
different assignments are
equally possible.
Table 6: Preferred Signal Routing in First 8-Coax HDMI Cable 102.12
HDMI Input Raw Cable Boost Boost Output
Signal Name Connection 108.12 Device Device Connection
212 Input Output 214
TMDS Data2 Shield txD2s 1208A.shield --> --> rxD2s
TMDS Data2+ txD2+ 1212.a D2+ C2+ rxD2+
TMDS Data2- txD2- 1212.b D2- C2- rxD2-
TMDS Datal Shield txD1s 1208A.shield --> --> rxDls
TMDS Datal+ txD1+ 1214.a D1+ C1+ rxD1+
TMDS Datal- txD1- 1214.b D1- Cl- rxD1-
TMDS Data0 Shield txDOs 1208A.shield --> --> rxDOs
TMDS Data0+ txDO+ 1208.a DO+ CO+ rxDO+
TMDS Data0- txDO- 1208.b DO- CO- rxDO-
- txCKs 1208A.shield -
-
TMDS Clock Shield
Pgm --> rxCKs
TMDS Clock+ txCK+ 1210.a D3+ C3+ rxCK+
TMDS Clock- txCK- 1210.b - C3- rxCK-
DDC/CEC Ground txGnd 1208A.shield GND --> rxGnd
CEC txCEC 1210A.shield --> --> rxCEC
SCL txSCL 1212.shield --> --> rxSCL
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SDA txSDA 1214.shield --> --> rxSDA
Utility txUt n/c - - rxUt
+5V Power txPWR 1208B.shield +5V --> rxPWR
Hot Plug Detect txHPD 1210B.shield --> --> rxHPD
...., ..
Single Ended Clock Concept
A concept of advantageously carrying an originally differential high speed
signal as a single-ended
signal is also illustrated in Fig. 12B. The First 8-Coax Output Paddle Board
116.12 includes a
Modified Boost Device 118.12, modified from the Boost Device 118 by omitting
the negative
polarity input D3- of the high speed differential signal input D3. Although
only a single ended
TMDS clock signal (txCK+ -> D3+) is thus received by the Modified Boost Device
118.12, the
Modified Boost Device 118.12 includes a single-ended to differential converter
(SDC) 1216 in
which the single ended clock input D3+ is converted to a differential signal,
and a differential output
is generated at the C3+ and C3- outputs of the Modified Boost Device 118.12.
The regenerated
differential clock signals (C3+, C3-) are coupled through the Output
Connection Field 214 to the
output of the First 8-Coax HDMI Cable 102.12 as rxCK+ and rxCK-, and thus the
Video Sink
Device 106 receives a standard differential clock.
The high speed TMDS Clock signal is received from the Video Source Device at
the terminals
txCK+ and txCK-, and transmitted through the padding resistors R19 and R20, to
the inner
conductors of the coax lines 1210A and 1210B respectively of the split dual
shielded cable element
1210. Only the positive polarity of the clock signal corresponding to txCK+ is
coupled from the
output of the inner conductor of the coax line 1210A to the D3+ input of the
Modified Boost Device
118.12. The negative polarity of the signal is terminated at the output from
the inner conductor of
the coax line 1210B on a terminating resistor R21, the terminating resistor
R21 being connected to a
common output ground node 1218 of the First 8-Coax Output Paddle Board 116.12.
The resistance
value of the terminating resistor R21 should match the impedance of the coax
line 1210B, which
may be for example 35 ohms.
The single ended clock concept advantageously exploits the fact that the Video
Source Device 104
drives a differential current mode signal which is designed to be terminated
in an input circuit of the
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Video Sink Device 106 (or a boost device) to provide terminating pull-up
resistors connected to a
bias voltage to each of the two lines of the differential signal path. However
in the proposed single
ended clock concept, only one of the two lines of the differential signal path
is biased by a
terminating pull-up resistor in the boost device, the other line being
grounded through an external
.. resistor and thus becoming inactive. As a result, the clock signal,
although nominally generated as a
differential signal, travels as a single ended signal. Several advantages may
be obtained from this
embodiment: the shield of the single ended clock line txCK+ is used to carry
the HPD signal which
is normally completely static, and thus no interference is coupled from this
shield to txCK+; one
external signal pin is saved in the boost device; and less current needs to be
supplied by the boost
device for receiving the single ended signal compared to a differential
signal, thus leaving more
power available for other functions of the boost device.
While the termination resistor R21 is preferably realized as a component on
the First 8-Coax Output
Paddle Board 116.12, it may also be contained in the boost device instead. The
termination resistor
R21 may be an actual resistor or a resistance element otherwise realized, and
may also be referred to
as a termination element.
In some applications the SDC 1216 may also be realized independently of the
boost device and can
so also be used without the boost device in a cable where boosting of other
high speed signals is not
required.
Carrying a Signal on the Cable Braid
Figure 13A illustrates an expanded generic diagram 1300 of the generic Boosted
Digital Video
Cable 102.j of Fig. 2, including: the Raw Cable 108.j comprising a Metallic
Outer Cable Braid also
referred to simply as "Outer Braid", or "Braid" 1302 which encloses signal
lines of various types;
the Input Connector 110 comprising a metallic Input Connector Shell 1304 which
partially encloses
the Input Connection Field 212 and the Input Paddle Board 114.j; and the
Output Connector 112
comprising a metallic Output Connector Shell 1306 which partially encloses the
Output Connection
Field 214 and the Output Paddle Board 116.j. The Metallic Outer Cable Braid
1302 provides a
galvanic connection between the Input Connector Shell 1304 and the Output
Connector Shell 1306,
and provides Electromagnetic Interference (EMI) shielding to the entire cable
assembly. Normally,
the Connector Shells 1304 and 1306 are grounded, and connected with each other
through the braid.
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The cable braid also provides an electrical path from the input connector to
the output connector. In
a "Signal on the Braid" concept described below, the cable braid is used in an
alternative cable
configuration to carry one of the HDMI signals, allowing fourteen HDMI signals
to be carried in a
cable comprising only eight coax lines.
Figure 13B illustrates a general diagram of a Second 8-Coax HDMI Cable 102.13,
which includes a
Second 8-Coax Input Paddle Board 114.13, a Second 8-Coax Raw Cable 108.13, and
a Second 8-
Coax Output Paddle Board 116.13. The Second 8-Coax Raw Cable 108.13 includes
the Metallic
Outer Cable Braid 1302, and the Second 8-Coax Input Paddle Board 114.13 and
the Second 8-Coax
Output Paddle Board 116.13 are partially enclosed in the Input and Output
Connector Shells 1304
and 1306 of the Input and Output Connectors 110 and 112 respectively.
Instead of being directly joined to the metallic shells, as shown in Fig. 13A,
the Metallic Outer
Cable Braid 1302 is connected to the Input and Output Connector Shells 1304
and 1306 through
isolating capacitors C3 and C4 of 0.1 to 1.0 pF, mounted on the Second 8-Coax
Input and Output
Paddle Boards 114.13 and 116.13 respectively, to provide required EMI
shielding. At the same
time, the Metallic Outer Cable Braid 1302 is connected to the txHPD and rxHPD
signal terminals,
to provide a conductive path for the HPD signal. As is well known, the HPD
signal is a quasi-static
signal whose purpose is to inform the sink and source devices of their mutual
connectedness
through the cable. By connecting the HPD signal through the cable braid, this
purpose is fulfilled
without the need for a separate signal wire in the cable. It should be noted
that the technique of
carrying an auxiliary signal on the cable braid is not limited to just the HPD
auxiliary signal. It is
potentially valid for any auxiliary signal.
Figure 14 shows a detailed diagram of the Second 8-Coax HDMI Cable 102.13 of
Fig. 13B,
including detailed diagrams of the Second 8-Coax Input Paddle Board 114.13,
the Second 8-Coax
Raw Cable 108.13, and the Second 8-Coax Output Paddle Board 116.13.
The Second 8-Coax HDMI Cable 102.13 incorporates one split dual shielded cable
element 1308
comprising two coax lines (1308A and 1308B) and a coupling capacitor C5.
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The Second 8-Coax HDMI Cable 102.13 incorporates in the Second 8-Coax Raw
Cable 108.13 and
a corresponding coupling capacitor C5 mounted on the Second 8-Coax Input
Paddle Board 114.13.
The Second 8-Coax Raw Cable 108.13 further includes three dual shielded cable
elements, that is
coax pairs 1310, 1312, and 1314,
The Second 8-Coax Input and Output Paddle Boards 114.13 and 116.13
respectively are arranged to
provide connectivity between the Input and Output Connection Fields 212 and
the Second 8-Coax
Raw Cable 108.13. The Second 8-Coax Input Paddle Board 114.13 further includes
padding
resistors R22 to R29, analogous to the padding resistors R1 to R8 of Fig. 10,
each padding resistor
connected in series between a TMDS signal or clock terminal of the Input
Connection Field 212 and
one of the eight shielded conductors of the dual or split dual shielded cable
elements.
The resistance value of each of the padding resistors R22 to R29 is determined
as the difference
between one half of the nominal differential impedance of the Second 8-Coax
HDMI Cable 102.13,
that is 100 ohms for each of the high speed differential data signals, and the
impedance of each of
the coaxial lines. For example, when 35-ohm coax lines are used in the Second
8-Coax Raw Cable
108.13, each padding resistor (R22 to R29) should have a resistance of 15
ohms, so that the nominal
differential HDMI impedance of 100 ohms is present at the Input Connection
Field 212.
The padding resistors R22 to R29 are omitted when 50-ohm coax lines are used.
Alternatively (not
shown in Fig. 14), shunt resistors analogous to the shunt resistors R9 to R12
of Fig. 11 would be
used where coax lines of a higher impedance than 50 ohms are used in the raw
cable.
.. As shown in Fig. 13B, the TMDS HPD signal is carried over the Metallic
Outer Cable Braid 1302.
The Second 8-Coax Input Paddle Board 114.13 includes an Electrostatic
Discharge (ESD) resistor
R30 of about 30 ohms in series between the txHPD signal of the Input
Connection Field 212 and the
Metallic Outer Cable Braid 1302. Similarly, the Second 8-Coax Output Paddle
Board 116.13
includes an ESD resistor R31 of about 30 ohms in series between the Metallic
Outer Cable Braid
1302 and the rxHPD signal of the Output Connection Field 214. The Second 8-
Coax Input and
Output Paddle Boards 114.13 and 116.13 further comprise bypass capacitors C6
and C7
respectively, each having a capacitance of about 1 nF, connected between
ground (txGnd and
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rxGnd respectively) and the HPD terminal (txHPD and rxHPD respectively). The
purpose of the
bypass capacitors C6 and C7 is to dampen any ESD spikes that may occur when
the Second 8-Coax
HDMI Cable 102.13 is plugged into the video equipment, in order to protect its
circuitry.
A preferred signal routing in the Second 8-Coax HDMI Cable 102.13 is
illustrated in Fig. 14 and
shown in Table 7 below. The differential TMDS Data signals and the TMDS Clock
signal are
coupled through the padding resistors R22 to R29 to the inner (shielded)
conductors of the eight
coax lines.
The joined shields of the dual shielded cable elements 1310, 1312, and 1314
are connected to carry
respectively the HDMI signals SCL, SDA, and CEC.
The shields of the two coax lines 1308B and 1308A of the split dual shielded
cable element 1308
are connected to carry respective two static signals namely: DDC/CEC Ground
and +5V Power.
Preferred signal assignments of the Second 8-Coax HDMI Cable 102.13 are shown
Fig. 14 and in
Table 7 below as examples, and different assignments may be equally valid.
Table 7: Preferred Signal Routing in Second 8-Coax HDMI Cable 102.13
HDMI Input Raw Cable Boost Boost Output
Signal Name Connection 108.13 Device Device Connection
212 Input Output 214
TMDS Data2 Shield txD2s 1308A.shield --> --> rxD2s
TMDS Data2+ txD2+ 1310.a D2+ C2+ rxD2+
TMDS Data2- txD2- 1310.b D2- C2- rxD2-
TMDS Datal Shield txDls 1308A.shield --> --> rxDls
TMDS Datal+ txD1+ 1312.a D1+ Cl+ rxD1+
TMDS Datal- txD1- 1312.b D1- Cl- rxD1-
TMDS Data Shield txDOs 1308A.shield --> --> rxDOs
TMDS Data0+ txDO+ 1314.a DO+ CO+ rxDO+
TMDS Data0- txDO- 1314.b DO- CO- rxDO-
txCKs 1308A.shield - - -
TMDS Clock Shield
Pgm --> rxCKs
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TMDS Clock+ txCK+ 1308.a D3+ C3+ rxCK+
TMDS Clock- txCK- 1308.b D3- C3- rxCK-
DDC/CEC Ground txGnd 1308A.shield GND --> rxGnd
CEC txCEC 1314.shield --> --> rxCEC
SCL txSCL 1310.shield --> --> rxSCL
SDA txSDA 1312.shield --> --> rxSDA
Utility txUt n/c rxUt
+5V Power txPWR 1308B.shield +5V --> rxPWR
Hot Plug Detect txHPD 1302(braid) --> --> rxHPD
Unboosted Cables
The techniques described above for carrying signals on the shields of coax
lines or STP lines are
also valuable when no boost device is integrated in the cable.
While the Boosted Digital Video Cables 102.j include the Boost Device 118 or
the Modified Boost
Device 118.12, which facilitate use of these cables over greater distances,
equivalent unboosted
cables can provide the same facilities as the boosted cables but for use over
shorter distances,
typically not exceeding 2.0 meters for AWG34 wire gauge, 2.5 meters for AWG30
or 5 meters for
AWG28 wire gauge depending on physical properties such as intrinsic impedance,
capacitance etc.
Figure 15 shows a configuration 1500 of a generic Unboosted Digital Video
Cable 1502.k which
may be any of a number of types described in the following figures, according
to embodiments of
the invention, interconnecting the Video Source Device (Tx) 104 and the Video
Sink Device (Rx)
106. The generic Unboosted Digital Video Cable 1502.k is similar in all
respects to the generic
Boosted Digital Video Cable 102.j, j = k, with the difference being an
Unboosted Output Paddle
Board 1504.k which replaces the Output Paddle Board 116.j of the generic
Boosted Digital Video
Cable 102.j.
Various embodiments of the Unboosted Digital Video Cables 1502.k of the
invention, described in
more detail below, make use of the same Input Paddle Boards 114.j and the same
Raw Cables 108.j,
CA 2961317 2018-07-16
as corresponding boosted cables, including the inventive techniques described
earlier, of carrying
signals on the shields of dual shielded cable elements, i.e. coax pairs (Figs.
3, 5, 7, 10, 11) or
Shielded Twisted Pairs 302 to 310 (Figs. 4, 6, 8), or of split dual shielded
cable elements as shown
in Fig. 14 which also includes the concept of carrying a signal on the
Metallic Outer Cable Braid
1302.
With the exception of the First 8-Coax HDMI Cable 102.12 which relies on the
single-ended to
differential converter (SDC) 1216 in the Modified Boost Device 118.12, all
previously described
boosted digital video cables have an unboosted cable equivalent, as shown in
Table 8 below which
lists for all described cable types reference numbers showing corresponding
boosted and unboosted
cable versions. 102.10
Table 8: Boosted and Unboosted Digital Video Cable equivalents
Cable Type Boosted Raw Unboosted Unboosted Output
Cable Cable Cable Paddle Board
HDMI, coax 102.1 108.1 1502.1 1504.1
HDMI, STP 102.2 108.2 1502.2 1504.2
HDMI+HEAC, coax 102.3 108.3 1502.3 1504.3
HDMI+HEAC, STP 102.4 108.4 1502.4 1504.4
DisplayPort, coax 102.5 108.5 1502.5 1504.5
DisplayPort, STP 102.6 108.6 1502.6 1504.6
Low-ZO coax HDMI 102.10 108.1 1502.10 1504.10
High-ZO coax HDMI 102.11 108.1 1502.11 1504.11
First 8-coax HDMI 102.12 108.12 N/A N/A
Second 8-coax HDMI 102.13 108.13 1502.13 1504.13
Figures 16 to 24 showing unboosted cable types are distinguished from the
otherwise identical
corresponding figures of boosted cable types, by new Unboosted Output Paddle
Boards 1504.k,
shown in bold outline in the drawings. These Unboosted Output Paddle Boards
1504.k may be
realized as identical mirror images of the corresponding Input Paddle Boards
114.j, k = j.
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Figure 16 shows a Basic Unboosted Coax HDMI Cable 1502.1 based on coax
technology according
to an embodiment of the invention, including the Input Connection Field 212,
the first Input Paddle
Board 114.1, the first Raw Cable 108.1, the Output Connection Field 214, as
well as a first
Unboosted Output Paddle Board 1504.1.
Figure 17 shows a Basic Unboosted STP HDMI Cable 1502.2 based on Shielded
Twisted Pair
(STP) technology according to an embodiment of the invention, including the
Input Connection
Field 212, the second Input Paddle Board 114.2, the second Raw Cable 108.2,
the Output
Connection Field 214, as well as a second Unboosted Output Paddle Board
1504.2.
Figure 18 shows an Unboosted HEAC-Capable Coax HDMI Cable 1502.3 based on coax
technology according to an embodiment of the invention, including the HEAC-
capable Input
Connection Field 412, the third Input Paddle Board 114.3, the third Raw Cable
108.3, the HEAC-
capable Output Connection Field 414, as well as a third Unboosted Output
Paddle Board 1504.3.
Figure 19 shows an Unboosted HEAC-Capable STP HDMI Cable 1502.4 based on
Shielded
Twisted Pair (STP) technology according to an embodiment of the invention,
including the HEAC-
capable Input Connection Field 212, the fourth Input Paddle Board 114.4, the
fourth Raw Cable
108.4, the HEAC-capable Output Connection Field 214, as well as a fourth
Unboosted Output
Paddle Board 1504.4.
Figure 20 shows an Unboosted Coax DisplayPort Cable 1502.5 based on coax
technology according
to an embodiment of the invention, including the DisplayPort Input Connection
Field 612, the fifth
Input Paddle Board 114.5, the fifth Raw Cable 108.5, the DisplayPort Output
Connection Field 614,
as well as a fifth Unboosted Output Paddle Board 1504.5.
Figure 21 shows an Unboosted STP DisplayPort Cable 1502.6 based on Shielded
Twisted Pair
(STP) technology according to an embodiment of the invention, including the
DisplayPort Input
Connection Field 612, the sixth Input Paddle Board 114.6, the sixth Raw Cable
108.1, the
DisplayPort Output Connection Field 614, as well as a sixth Unboosted Output
Paddle Board
1504.6.
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Figure 22 shows an Unboosted Low-Impedance Coax HDMI Cable 1502.10 which is
identical to
the Basic Unboosted Coax HDMI Cable 1502.1 of Fig. 16 except for the Low-
Impedance Input
Paddle Board 114.10 instead of the first Input Paddle Board 114.1, and
includes the Input
Connection Field 212, the first Raw Cable 108.1, the Output Connection Field
214, as well as a
Low-Impedance Unboosted Output Paddle Board 1504.10.
The Low-Impedance Unboosted Output Paddle Board 1504.10 includes padding
resistors R32 to
R39 which correspond to the padding resistors R1 to R8 of the Low-Impedance
Input Paddle Board
114.10 and in combination with a low-impedance raw cable provide the correct
nominal cable
impedance at the cable connectors according to the HDMI specification.
Figure 23 shows an Unboosted High-Impedance Coax HDMI Cable 1502.11 which is
identical to
the Basic Unboosted Coax HDMI Cable 1502.1 of Fig. 16 except for the High-
Impedance Input
Paddle Board 114.11 instead of the first Input Paddle Board 114.1, and
includes the Input
Connection Field 212, the first Raw Cable 108.1, the Output Connection Field
214, as well as a
High-Impedance Unboosted Output Paddle Board 1504.11.
The High-Impedance Unboosted Output Paddle Board 1504.11 includes shunt
resistors R40 to R43
which correspond to the shunt resistors R9 to R12 of the High-Impedance Input
Paddle Board
114.10 and in combination with a high-impedance raw cable provide the correct
nominal cable
impedance at both cable connectors according to the HDMI specification.
Figure 24 shows an Unboosted Low-Impedance 8-Coax HDMI Cable 1502.13,
including the Input
Connection Field 212, the Second 8-Coax Input Paddle Board 114.13, the Second
8-Coax Raw
Cable 108.13, the Output Connection Field 214, as well as a Low-Impedance
Unboosted Output
Paddle Board 1504.13.
The Low-Impedance Unboosted Output Paddle Board 1504.13 is similar to the
Second 8-Coax
Output Paddle Board 116.13 of Fig. 14, but instead of the Boost Device 118
comprises padding
resistors R44 to R51 analogous to the padding resistors R22 to R29 of the
Second 8-Coax Input
Paddle Board 114.13, each padding resistor connected in series between a TMDS
high speed data or
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CA 2961317 2018-07-16
clock terminal of the Output Connection Field 214 and one of the eight
shielded conductors of the
dual or split dual shielded cable elements of the Second 8-Coax Raw Cable
108.13.
The Low-Impedance Unboosted Output Paddle Board 1504.13 further includes: an
ESD resistor
.. R52 an isolating capacitor C9; and a bypass capacitor C10, these components
corresponding to the
ESD resistor R31, the isolating capacitor C4 and the bypass capacitor C7 of
the Second 8-Coax
Output Paddle Board 116.13, for permitting the HDMI HPD signal to be carried
over the Metallic
Outer Cable Braid 1302 of the Second 8-Coax Raw Cable 108.13.
A large number of cable versions, boosted and unboosted, have been briefly
described. Further
combinations of the described features may be readily devised, for example
cables similar to the
Second 8-Coax HDMI Cable 102.13 or the Unboosted Low-Impedance 8-Coax HDMI
Cable
1502.13, but employing eight coax lines of the correct (50 ohms) impedance,
thus avoiding padding
resistors. The use of dual shielded cable elements and a split dual shielded
cable element as well as
the metallic cable braid permits such a cable to carry to carry 14 HDMI
connections. Another
example would be a cable of eight high-impedance coax lines, requiring shunt
resistors for proper
impedance matching when high-impedance coax lines are employed. No padding or
shunt resistors
are needed when coax lines of the nominal (50 ohms for HDMI) impedance are
used.
Although various exemplary embodiments of the invention have been disclosed,
it should be
apparent to those skilled in the art that various changes and modifications
can be made which will
achieve some of the advantages of the invention without departing from the
true scope of the
invention.
For example, the following elements according to various exemplary embodiments
of the invention
described above may be combined to advantage in applications such as an HDMI
cable with or
without HEAC capability, a Display Port cable, or similar high speed data
cables: boosting of
differential signals; carrying an auxiliary signal including power and ground
on the common shield
of a dual shielded cable element which may be a pair of coaxial lines or a
shielded twisted pair;
carrying auxiliary signals including power and ground on the individual
shields of a split dual
shielded cable element; carrying an auxiliary signal including power and
ground on the cable braid;
using raw cable elements of lower or higher impedance than the impedance
specified for the cable,
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CA 2961317 2018-07-16
and correcting the impedance with a resistor network (series or shunt
resistors respectively);
carrying a differential high speed signal through the cable, but retrieving
only one polarity of the
signal to be subsequently restored at the cable end in a single-ended to
differential converter.
.. Thus, a high speed video cable carrying signals according to the High-
Definition Multimedia
Interface (HDMI), and including a raw cable and in some embodiments including
a boost device,
has been provided. The raw cable includes coaxial lines which are covered by
an outer metallic
braid. Each of four high speed video signals is carried on the inner
conductors of a pair of coaxial
lines. Lower speed signals are carried on the galvanically or capacitively
coupled shields of a pair of
coaxial lines, as well as the braid of the cable, thus permitting fourteen
HDMI signals to be carried
in a cable comprising only eight coaxial lines, resulting in a simpler and
lower cost production and
assembly of the cable. When present, the boost device receives only one of the
polarities of one of
the high speed video signals, and generates a differential signal therefrom.
In one embodiment, 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. In yet another embodiment, the raw
cable is constructed with
either Shielded Twisted Pairs (STP) or coaxial lines which carry all signals
on either shielded
conductors or their shields. Some auxiliary signals including power are
carried on ungrounded
shields. This achieves a reduction in the number of wires in the cable leading
to a thinner, lighter,
and less costly HDMI or DisplayPort Cable. The use of a uniform technology,
either STP or coax,
.. also permits simpler and lower cost production and assembly of the cable.
A person understanding this invention may now conceive of alternative
structures and embodiments
or variations of the above all of which are intended to fall within the scope
of the invention as
defined in the claims that follow.
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