US20170230204A1 - System for transmitting control signals over twisted pair cabling using common mode of transformer - Google Patents
System for transmitting control signals over twisted pair cabling using common mode of transformer Download PDFInfo
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- US20170230204A1 US20170230204A1 US15/016,710 US201615016710A US2017230204A1 US 20170230204 A1 US20170230204 A1 US 20170230204A1 US 201615016710 A US201615016710 A US 201615016710A US 2017230204 A1 US2017230204 A1 US 2017230204A1
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- 238000010624 twisted pair cabling Methods 0.000 title claims abstract description 9
- 230000005540 biological transmission Effects 0.000 claims description 24
- 238000002955 isolation Methods 0.000 claims description 11
- 239000003990 capacitor Substances 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 5
- 238000004891 communication Methods 0.000 description 16
- 238000010586 diagram Methods 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000006855 networking Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0264—Arrangements for coupling to transmission lines
- H04L25/0272—Arrangements for coupling to multiple lines, e.g. for differential transmission
- H04L25/0276—Arrangements for coupling common mode signals
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/54—Systems for transmission via power distribution lines
- H04B3/56—Circuits for coupling, blocking, or by-passing of signals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0264—Arrangements for coupling to transmission lines
- H04L25/0266—Arrangements for providing Galvanic isolation, e.g. by means of magnetic or capacitive coupling
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0264—Arrangements for coupling to transmission lines
- H04L25/028—Arrangements specific to the transmitter end
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0264—Arrangements for coupling to transmission lines
- H04L25/028—Arrangements specific to the transmitter end
- H04L25/0282—Provision for current-mode coupling
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0264—Arrangements for coupling to transmission lines
- H04L25/0292—Arrangements specific to the receiver end
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/20—Arrangements affording multiple use of the transmission path using different combinations of lines, e.g. phantom working
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/189—High-frequency amplifiers, e.g. radio frequency amplifiers
- H03F3/19—High-frequency amplifiers, e.g. radio frequency amplifiers with semiconductor devices only
- H03F3/195—High-frequency amplifiers, e.g. radio frequency amplifiers with semiconductor devices only in integrated circuits
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N7/00—Television systems
- H04N7/10—Adaptations for transmission by electrical cable
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N7/00—Television systems
- H04N7/10—Adaptations for transmission by electrical cable
- H04N7/108—Adaptations for transmission by electrical cable the cable being constituted by a pair of wires
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49002—Electrical device making
- Y10T29/4902—Electromagnet, transformer or inductor
Definitions
- Ethernet has become a widespread method of transmitting information over local area networks.
- Ethernet is a common term used to describe the link layer and physical layer standards of communication.
- Ethernet often communicates over twisted pair cabling using the various 10-BaseT, 100-BaseT, 1000BaseT, or 10GBaseT standards.
- Ethernet may also be transmitted using the HDBaseT standard and twisted pair cabling.
- HDBaseT is also able to transmit audio and video signals, as well as power and usb signals over traditional twisted pair cabling, typically Cat5e or Cat6 cabling.
- transmission of control signals traditionally requires an additional cable. This causes problems were one cable breaks and the other remains: for example, the control cable breaks, but the video cable remains. Using multiple types of cables causes problems in installations with multiple channels, where the cable carrying the control signal may be mistakenly associated with the wrong Ethernet cable.
- FIG. 1 is a block diagram of an exemplary display system in accordance with some embodiments.
- FIG. 2 is an electrical drawing of more detailed of the transmission circuitry in accordance with some embodiments.
- This disclosure provides a display system and a method for transmission of control data over twisted pair cabling, for example, cabling used in conjunction with HDBaseT communications.
- the term “adapter” refers to either an external display dongle, an internal dongle, a controller card in a display, or a daughter card mounted or connected to a controller card in a display.
- a graphics card communicates with an adapter in communication with a display.
- the graphics card is used in conjunction with a computer.
- the graphics card in conjunction with the adapter provide for control signals to be transmitted by the computer system to a display via the adapter.
- the host system containing the graphics card may send control signals to a display in communication with the adapter over a side-band signal that does not require the display to be powered on.
- the control signals are differential signals electrically superimposed on the communications signals (in HDBaseT, Pulse Amplitude Modulation (“PAM”) signals), acting as a side-band signal.
- PAM Pulse Amplitude Modulation
- FIG. 1 is a block diagram of an exemplary display system in accordance with some embodiments.
- a display system 100 includes a graphics card 110 , a display 160 , and a display adapter 140 .
- the graphics card 110 may be plugged onto a motherboard (not shown) of a PC via, for example, a PCI Express Interface 111 .
- the graphics card 110 may include a graphics processing unit (“GPU”) 112 , a video converter 114 , an audio/video (“A/V”) transmitter 116 , a transformer 118 , an RJ45 connector 120 , a memory 122 , and a controller 124 connected to a serial port, such as USB port 126 .
- GPU graphics processing unit
- A/V audio/video
- the GPU 112 is connected to the video converter 114 , for example, a Display Port to HDMI converter.
- the GPU 112 provides, for example, video data via Display Port interface to the video converter 114 .
- Display Port is a digital display interface developed by the Video Electronics Standards Association (VESA), and is primarily used to connect a video source to a computer display, though it can also be used to carry audio, USB, and other forms of data.
- VESA Video Electronics Standards Association
- Alternative embodiments do not include a GPU 112 , but rather receive a Display Port signal at the Display Port to HDMI converter 114 or altogether bypass the Display Port to HDMI converter 114 and receive an HDMI signal at transmitter 116 .
- the output of the video converter 114 is connected to the audio/video transmitter 116 and to an EDID (EEPROM) 122 .
- the video converter 114 receives and outputs video data to audio/video transmitter 116 via HDMI interface.
- the audio/video transmitter 116 is further connected to the transformer 118 and transmits audio/video signal.
- Existing technology examples of an audio/video transmitters and receivers are: Valens chipsets utilizing HDBaseT standard and Aptovision BlueRiver chipsets using standard IP based systems. Those skilled in the art after reading this disclosure would appreciate that other chip sets with other standards could be used as the audio video transmitter 116 .
- the audio/video signal may be HDBaseT.
- HDBaseT is a consumer electronic and commercial connectivity standard for transmission of uncompressed high-definition video, audio, power, home networking, Ethernet, USB, and some control signals, over a common category (ordinary Cat5 may be used, but Cat6e or above provides for longer reach) cable with a standard connector (RJ45).
- RV45 standard connector
- HDBaseT can be transmitted over category 6 a cables or above up to 100 meter, or even longer, with 8P8C modular connectors of the type commonly used for local area network connections.
- the transformer 118 is designed and manufactured to comply with the appropriate standard, such as HDBaseT standards.
- the video data from the audio/video transmitter 116 is sent to a local area network 130 , such as Ethernet, by using the RJ45 connector 120 .
- a local area network 130 such as Ethernet
- HDBaseT supports the 100 Mbit/s version of Ethernet over twisted pair known as 100BASE-T. This can provide Internet access, or enable televisions, stereos, computers and other devices to communicate with each other and access multimedia content, including video, pictures and music stored on the local network.
- the controller 124 is connected to the EDID (EEPROM) 122 and both sides of the transformer 118 .
- the controller 124 may be a digital signal processor, a processor, a microprocessor, or a microcomputer on a chip.
- controller 124 and controller 148 are low power microprocessors.
- the controller 124 transmits and receives control information to and from a controller 148 on the communications adapter 140 through side-band communication. This control information may be transmitted using the CEC standard over novel differential signals superimposed on the PAM communications that occurs over the cabling 130 . More detail on this novel electrical circuit is described with respect to FIG. 2 below.
- the display 160 in communication with adapter 140 need not be powered on for this control communication to occur.
- the display adapter 140 includes an RJ45 connector 142 , a transformer 144 , audio/video receiver 146 , and the controller 148 .
- the transformer 144 is designed and manufactured to comply with the appropriate standard, such as the HDBaseT standards.
- the audio/video receiver 146 receives video data from the audio/video transmitter 116 , by using the RJ45 connector 142 and the local area network 130 .
- the display 160 is connected to the display adapter 140 via HDMI interface.
- a memory 162 (such as EEPROM) storing an EDID of the display 160 is powered by HDMI interface even if the display is turned off.
- the controller 148 may be a digital signal processor, a processor, a microprocessor, or a microcomputer on a chip.
- the controller 148 of the display adapter 140 communicates with controller 124 of graphics card 110 to facilitate the transfer of control signals between the display 162 and the graphics card 110 .
- the host computer can effectively issue commands or requests to the display 160 .
- the controllers 124 and 148 may cooperate to issue commands to the display 160 using the CEC protocol.
- the host computer can issue commands to, for example, turn displays on or off; adjust contrast or brightness; or adjust color.
- CEC can also be used to query information from the displays, such as the model, serial number, and manufacturing date of the display.
- FIG. 2 is an electrical drawing in more detail of the transmission circuitry in accordance with some embodiments.
- Controller 124 communicates using single ended UART (“Universal Asynchronous Receiver/Transmitter”) transmitter (TX) and receiver (RX) signals to a UART to RS485 converter 212 .
- the UART to RS485 converter 212 converts, at differential transmitter 215 , the TX from single ended UART signal to a differential signal on two wires and converts, at differential receiver 220 , incoming RS485 two wire signals to a single UART signal.
- TX Universal Asynchronous Receiver/Transmitter
- RX receiver
- the transmit signals are placed on the center taps of coils A and D, respectively.
- the received signals are received from the center taps of coils B and C, respectively.
- the outside taps of coils A, B, C, and D contain the communications signals, for example the HDBaseT PAM signals. This is done because the power level and ground at the graphics card 110 may be different from the power level and ground at adapter 140 .
- the transformer 118 and 144 provide galvanic isolation.
- Power supply 235 of +12 volts goes into the center tap of coil A and the minus side of power supply goes into the center tap of coil B.
- power is transmitted on the common mode of the transformer. Any voltage could of course be used.
- the power is transmitted across the twisted pair cabling to the display side.
- the power is retrieved from the center taps of the coils and goes to DC to DC isolation converter 210 providing power to whatever needs it at the adapter 140 side.
- the power supply is tightly held at, for example, 12 volts and varies slightly with the PAM signal that is carried over the twisted pair.
- power is injected at, for example, 12 volts by the graphics card 110 and power is extracted by the adapter 140 .
- the adapter controller 148 has a similar configuration to that described in the previous paragraphs.
- Adapter controller 148 also communicates using UART single ended transmission (TX) and receiver (RX) UART signals to UART to RS485 converter 222 .
- UART to RS485 converter 222 converts, at differential transmitter 230 , the TX from single ended UART signals to a differential signal on two wires and converts, at differential receiver 225 , incoming RS485 two wire signals to a single UART signal. By using a two wire signal, there is common mode noise rejection. Once the signal has been differentialized, it is placed on the twisted pair cable using the common mode of transformer 144 .
- the receive signals are received from the center taps of coils A and D, respectively.
- the transmit signals are transmitted from the center taps of coils B and C, respectively.
- the outside taps of coils A, B, C, and D contain the communications signals, for example the HDBaseT PAM signals.
- Isolation capacitors are used on both sides to isolate the circuits on each side from the other side.
- Biasing circuits 240 and 250 provide potential on the otherwise floating receiver differential circuit.
- each of the three resistors is 100 kilo ohms.
- the above system uniquely uses the common mode of the transformer in order to communicate side-band control signals from a graphics card to an adapter. These signals are superimposed over the standard communications signals that are placed on the twisted pair cabling.
- control signals can be transmitted and received, even if the display system is powered off.
- the power on the primary side of the transformers showing 1.8V maybe be 0V when the system is powered off, but the differential signals on the secondary transformer side will still work the same.
- the power to the common mode of the secondary side of the transformers showing 12V may be 0V when the system is powered off, but the differential signals superimposed on these signals will continue to operate at a different bias level.
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Abstract
Description
- Ethernet has become a widespread method of transmitting information over local area networks. Ethernet is a common term used to describe the link layer and physical layer standards of communication. At the physical layer, Ethernet often communicates over twisted pair cabling using the various 10-BaseT, 100-BaseT, 1000BaseT, or 10GBaseT standards. Ethernet may also be transmitted using the HDBaseT standard and twisted pair cabling. HDBaseT is also able to transmit audio and video signals, as well as power and usb signals over traditional twisted pair cabling, typically Cat5e or Cat6 cabling. However, transmission of control signals traditionally requires an additional cable. This causes problems were one cable breaks and the other remains: for example, the control cable breaks, but the video cable remains. Using multiple types of cables causes problems in installations with multiple channels, where the cable carrying the control signal may be mistakenly associated with the wrong Ethernet cable.
- Even where prior art communications systems communicate both video and control signals over the same cable, such systems, such as HDBaseT systems powered by Valens chips, require that both the receiving and the transmitting system be fully up and running. Thus, in a display system using HDBaseT to communicate between a computer and a display, both the display and the computer must be powered on. However, often times the displays are not powered on, so prior art systems do not enable remote turn on or control of the display. Leaving both systems constantly powered on in order to facilitate transmission and reception of control signals is quite power hungry.
- Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
-
FIG. 1 is a block diagram of an exemplary display system in accordance with some embodiments. -
FIG. 2 is an electrical drawing of more detailed of the transmission circuitry in accordance with some embodiments. - The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
- This disclosure provides a display system and a method for transmission of control data over twisted pair cabling, for example, cabling used in conjunction with HDBaseT communications. In this detailed description, the term “adapter” refers to either an external display dongle, an internal dongle, a controller card in a display, or a daughter card mounted or connected to a controller card in a display. A graphics card communicates with an adapter in communication with a display. The graphics card is used in conjunction with a computer. The graphics card in conjunction with the adapter provide for control signals to be transmitted by the computer system to a display via the adapter. Using, for example, the Consumer Electronics Control (“CEC”) protocol, the host system containing the graphics card may send control signals to a display in communication with the adapter over a side-band signal that does not require the display to be powered on. The control signals are differential signals electrically superimposed on the communications signals (in HDBaseT, Pulse Amplitude Modulation (“PAM”) signals), acting as a side-band signal. By using differential signals transmitted across separate pairs, noise and interference effects on the control signal is minimized.
-
FIG. 1 is a block diagram of an exemplary display system in accordance with some embodiments. As shown inFIG. 1 , adisplay system 100 is provided. Thedisplay system 100 includes agraphics card 110, adisplay 160, and adisplay adapter 140. Thegraphics card 110 may be plugged onto a motherboard (not shown) of a PC via, for example, a PCI Express Interface 111. Thegraphics card 110 may include a graphics processing unit (“GPU”) 112, avideo converter 114, an audio/video (“A/V”)transmitter 116, atransformer 118, anRJ45 connector 120, amemory 122, and acontroller 124 connected to a serial port, such asUSB port 126. TheGPU 112 is connected to thevideo converter 114, for example, a Display Port to HDMI converter. The GPU 112 provides, for example, video data via Display Port interface to thevideo converter 114. Display Port is a digital display interface developed by the Video Electronics Standards Association (VESA), and is primarily used to connect a video source to a computer display, though it can also be used to carry audio, USB, and other forms of data. - Alternative embodiments do not include a
GPU 112, but rather receive a Display Port signal at the Display Port toHDMI converter 114 or altogether bypass the Display Port toHDMI converter 114 and receive an HDMI signal attransmitter 116. - The output of the
video converter 114 is connected to the audio/video transmitter 116 and to an EDID (EEPROM) 122. Thevideo converter 114 receives and outputs video data to audio/video transmitter 116 via HDMI interface. The audio/video transmitter 116 is further connected to thetransformer 118 and transmits audio/video signal. Existing technology examples of an audio/video transmitters and receivers are: Valens chipsets utilizing HDBaseT standard and Aptovision BlueRiver chipsets using standard IP based systems. Those skilled in the art after reading this disclosure would appreciate that other chip sets with other standards could be used as theaudio video transmitter 116. The audio/video signal may be HDBaseT. HDBaseT is a consumer electronic and commercial connectivity standard for transmission of uncompressed high-definition video, audio, power, home networking, Ethernet, USB, and some control signals, over a common category (ordinary Cat5 may be used, but Cat6e or above provides for longer reach) cable with a standard connector (RJ45). As can be seen, in order to use the Valens or Aptovision system for control signals, all systems must be powered up. HDBaseT can be transmitted over category 6 a cables or above up to 100 meter, or even longer, with 8P8C modular connectors of the type commonly used for local area network connections. Thetransformer 118 is designed and manufactured to comply with the appropriate standard, such as HDBaseT standards. - The video data from the audio/
video transmitter 116 is sent to alocal area network 130, such as Ethernet, by using theRJ45 connector 120. For example, HDBaseT supports the 100 Mbit/s version of Ethernet over twisted pair known as 100BASE-T. This can provide Internet access, or enable televisions, stereos, computers and other devices to communicate with each other and access multimedia content, including video, pictures and music stored on the local network. - The
controller 124 is connected to the EDID (EEPROM) 122 and both sides of thetransformer 118. Thecontroller 124 may be a digital signal processor, a processor, a microprocessor, or a microcomputer on a chip. In certain embodiments,controller 124 andcontroller 148 are low power microprocessors. Thecontroller 124 transmits and receives control information to and from acontroller 148 on thecommunications adapter 140 through side-band communication. This control information may be transmitted using the CEC standard over novel differential signals superimposed on the PAM communications that occurs over thecabling 130. More detail on this novel electrical circuit is described with respect toFIG. 2 below. Thedisplay 160 in communication withadapter 140 need not be powered on for this control communication to occur. - The
display adapter 140 includes anRJ45 connector 142, atransformer 144, audio/video receiver 146, and thecontroller 148. Thetransformer 144 is designed and manufactured to comply with the appropriate standard, such as the HDBaseT standards. The audio/video receiver 146 receives video data from the audio/video transmitter 116, by using theRJ45 connector 142 and thelocal area network 130. - The
display 160 is connected to thedisplay adapter 140 via HDMI interface. A memory 162 (such as EEPROM) storing an EDID of thedisplay 160 is powered by HDMI interface even if the display is turned off. Thecontroller 148 may be a digital signal processor, a processor, a microprocessor, or a microcomputer on a chip. Thecontroller 148 of thedisplay adapter 140 communicates withcontroller 124 ofgraphics card 110 to facilitate the transfer of control signals between thedisplay 162 and thegraphics card 110. - As the
graphics card controller 124 is in communication with theadapter controller 148, the host computer, via theserial port 126, can effectively issue commands or requests to thedisplay 160. For example, thecontrollers display 160 using the CEC protocol. Using CEC, the host computer can issue commands to, for example, turn displays on or off; adjust contrast or brightness; or adjust color. CEC can also be used to query information from the displays, such as the model, serial number, and manufacturing date of the display. -
FIG. 2 is an electrical drawing in more detail of the transmission circuitry in accordance with some embodiments. This discloses a single channel.Controller 124 communicates using single ended UART (“Universal Asynchronous Receiver/Transmitter”) transmitter (TX) and receiver (RX) signals to a UART toRS485 converter 212. The UART toRS485 converter 212 converts, atdifferential transmitter 215, the TX from single ended UART signal to a differential signal on two wires and converts, atdifferential receiver 220, incoming RS485 two wire signals to a single UART signal. By using a two wire signal, there is common mode noise rejection. Once the signal has been differentialized, it is placed on the twisted pair cable using the common mode of thetransformer 118. In this exemplary figure, the transmit signals are placed on the center taps of coils A and D, respectively. The received signals are received from the center taps of coils B and C, respectively. The outside taps of coils A, B, C, and D contain the communications signals, for example the HDBaseT PAM signals. This is done because the power level and ground at thegraphics card 110 may be different from the power level and ground atadapter 140. Thetransformer -
Power supply 235 of +12 volts goes into the center tap of coil A and the minus side of power supply goes into the center tap of coil B. Thus, power is transmitted on the common mode of the transformer. Any voltage could of course be used. The power is transmitted across the twisted pair cabling to the display side. At the display side, the power is retrieved from the center taps of the coils and goes to DC toDC isolation converter 210 providing power to whatever needs it at theadapter 140 side. The power supply is tightly held at, for example, 12 volts and varies slightly with the PAM signal that is carried over the twisted pair. Thus, power is injected at, for example, 12 volts by thegraphics card 110 and power is extracted by theadapter 140. - The
adapter controller 148 has a similar configuration to that described in the previous paragraphs.Adapter controller 148 also communicates using UART single ended transmission (TX) and receiver (RX) UART signals to UART toRS485 converter 222. UART toRS485 converter 222 converts, atdifferential transmitter 230, the TX from single ended UART signals to a differential signal on two wires and converts, atdifferential receiver 225, incoming RS485 two wire signals to a single UART signal. By using a two wire signal, there is common mode noise rejection. Once the signal has been differentialized, it is placed on the twisted pair cable using the common mode oftransformer 144. In this exemplary figure, the receive signals are received from the center taps of coils A and D, respectively. The transmit signals are transmitted from the center taps of coils B and C, respectively. The outside taps of coils A, B, C, and D contain the communications signals, for example the HDBaseT PAM signals. - Isolation capacitors are used on both sides to isolate the circuits on each side from the other side.
Biasing circuits 240 and 250 provide potential on the otherwise floating receiver differential circuit. In one exemplary embodiment, each of the three resistors is 100 kilo ohms. - Thus, the above system uniquely uses the common mode of the transformer in order to communicate side-band control signals from a graphics card to an adapter. These signals are superimposed over the standard communications signals that are placed on the twisted pair cabling. By using side-band communications in conjunction with the power supply system described above, control signals can be transmitted and received, even if the display system is powered off. The power on the primary side of the transformers showing 1.8V maybe be 0V when the system is powered off, but the differential signals on the secondary transformer side will still work the same. Also, the power to the common mode of the secondary side of the transformers showing 12V may be 0V when the system is powered off, but the differential signals superimposed on these signals will continue to operate at a different bias level.
- The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.
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US20180059864A1 (en) * | 2016-08-29 | 2018-03-01 | Panasonic Avionics Corporation | Methods and systems for display device touch panels |
US10382098B2 (en) * | 2017-09-25 | 2019-08-13 | Nxp B.V. | Method and system for operating a communications device that communicates via inductive coupling |
US10390200B2 (en) | 2016-12-19 | 2019-08-20 | Nxp B.V. | Method and system for operating a communications device that communicates via inductive coupling |
US20190320532A1 (en) * | 2018-04-17 | 2019-10-17 | Tri-Net Electronics Co., Ltd. | Modular circuit board |
US10721604B2 (en) | 2016-12-19 | 2020-07-21 | Nxp B.V. | Method and system for operating a communications device that communicates via inductive coupling |
US10720967B2 (en) | 2017-09-25 | 2020-07-21 | Nxp B.V. | Method and system for operating a communications device that communicates via inductive coupling |
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CN101931468B (en) * | 2010-09-23 | 2013-06-12 | 武汉虹信通信技术有限责任公司 | Access system and method for transmitting Ethernet signal and mobile communication signal |
GB201018582D0 (en) * | 2010-11-03 | 2010-12-22 | Cable Sense Ltd | Apparatus for identifying interconnections and/or determining the physical state of cable lines in a network and associated components |
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Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20180059864A1 (en) * | 2016-08-29 | 2018-03-01 | Panasonic Avionics Corporation | Methods and systems for display device touch panels |
US9996193B2 (en) * | 2016-08-29 | 2018-06-12 | Panasonic Avionics Corporation | Methods and systems for display device touch panels |
US10390200B2 (en) | 2016-12-19 | 2019-08-20 | Nxp B.V. | Method and system for operating a communications device that communicates via inductive coupling |
US10721604B2 (en) | 2016-12-19 | 2020-07-21 | Nxp B.V. | Method and system for operating a communications device that communicates via inductive coupling |
US10382098B2 (en) * | 2017-09-25 | 2019-08-13 | Nxp B.V. | Method and system for operating a communications device that communicates via inductive coupling |
US10720967B2 (en) | 2017-09-25 | 2020-07-21 | Nxp B.V. | Method and system for operating a communications device that communicates via inductive coupling |
US20190320532A1 (en) * | 2018-04-17 | 2019-10-17 | Tri-Net Electronics Co., Ltd. | Modular circuit board |
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US20170324589A1 (en) | 2017-11-09 |
US9729357B1 (en) | 2017-08-08 |
US10193710B2 (en) | 2019-01-29 |
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