KVM extender based on optical fiber transmission

Abstract

A kind of KVM extender based on optical fiber transmission, including transmitter and receiver, and the transmitter and receiver are connected by a multimode optical fiber;Wherein, the transmitter includes: video input interface, first re-timer, USB-B interface, USB hub, USB audio decoding chip, first micro control unit, first field programmable gate array, first Ethernet physical layer chip and first fiber optic transceiver;The receiver includes second fiber optic transceiver, second re-timer, video output interface, second Ethernet physical layer chip, second field programmable gate array, audio output interface, USB-A interface and second micro control unit.The KVM extender based on optical fiber transmission of the utility model, by multimode optical fiber transmission DisplayPort video signal and USB data, realize long distance, high fidelity to DP video, USB audio, keyboard mouse signal and integrated extension.

Description

Technical Field

[0001] This utility model relates to the field of signal transmission technology, specifically to a KVM (Keyboard, Video, Mouse) extender for extending the distance between a computer host and peripheral devices (monitor, keyboard, mouse, audio devices). Background Technology

[0002] With the development of high-definition video, professional design, gaming, and esports, the demand for high-resolution, high-refresh-rate monitors is increasing. The DisplayPort (DP) interface, especially DP 1.4, supports high bandwidth (up to 32.4Gbps), enabling video transmission at 4K@144Hz, 8K@60Hz, and even higher resolutions.

[0003] However, traditional copper cable KVM extenders face the following bottlenecks when transmitting such high-bandwidth signals: 1. Limited transmission distance: Copper cables suffer from severe signal attenuation and can typically only reliably transmit DP 1.4 signals for 10-30 meters, which cannot meet the needs of long-distance applications such as large computer rooms, studios, and industrial control centers.

[0004] 2. Electromagnetic Interference (EMI): Copper cables are susceptible to interference from the surrounding electromagnetic environment, which can cause problems such as flickering, snow, and black screen in video images, affecting signal stability and transmission quality.

[0005] 3. Bandwidth bottleneck: In order to extend the distance, some copper cable extenders will compress the signal or reduce the resolution / refresh rate, which will greatly reduce the user experience.

[0006] 4. Heavy cables: Copper cables for transmitting high-bandwidth signals are usually thick, making wiring inconvenient and lacking in flexibility.

[0007] Although fiber optic transmission has advantages such as long distance, high bandwidth, and resistance to electromagnetic interference, some existing fiber optic extender solutions often have problems such as low integration, inability to transmit high-speed video and low-speed USB data simultaneously without loss, or high cost.

[0008] Therefore, there is an urgent need for a KVM extender solution that can stably transmit DisplayPort video, USB HID (keyboard / mouse), and USB audio simultaneously over long distances with high bandwidth, low latency, and a single optical fiber. Summary of the Invention

[0009] To address the aforementioned technical problems in the existing technology, this utility model provides a KVM extender based on optical fiber transmission. This extender transmits DisplayPort video signals and USB data through multimode optical fiber, achieving long-distance, high-fidelity, and integrated extension of DP video, USB audio, and keyboard / mouse signals.

[0010] To achieve the above objectives, this utility model provides a KVM extender based on fiber optic transmission, comprising a transmitter and a receiver connected via a multimode optical fiber; wherein, The transmitter includes: Video input interface: used to receive DP video signals from the computer host; First timer: Electrically connected to the video input interface, used to perform signal shaping and clock recovery on the input DP video signal to enhance the signal's driving capability and integrity; USB-B interface: Used to connect to a computer host to transmit USB data streams; USB hub: Connected to the USB-B interface, it is used to expand multiple downstream ports to connect multiple USB devices simultaneously, realizing the aggregation and splitting of data streams from multiple devices; USB audio decoding chip: connected to the USB hub, used to decode USB audio signals into digital audio format; First microcontroller unit: used to process USB HID signals and configure and control the first timer via the I2C bus; The first field-programmable gate array is connected to the AUX channel of the USB audio decoding chip, the first microcontroller unit, and the first timer, respectively, to package the digital audio signal and the downlink control signal of the AUX channel, and to separate the USB HID data and the uplink control signal of the AUX channel. First Ethernet physical layer chip: connected to the first field-programmable gate array (FPGA), used to convert the packetized data signal into a serial data stream suitable for fiber optic transmission; and First fiber optic transceiver: includes a fiber optic transmitter, which is connected to the first timer and the first Ethernet physical layer chip respectively, so as to combine the processed DP video signal and serial data stream into the same multimode fiber for transmission through photoelectric conversion; The receiver includes: Second fiber optic transceiver: includes a fiber optic receiver for receiving optical signals from multimode fiber and converting them into electrical signals, separating DP video signals and serial data streams; The second timer is connected to the second fiber optic transceiver and is used to perform clock recovery and signal shaping on the recovered DP video signal again to ensure the stability of the output signal. Video output interface: connected to the second timer, used to output the restored DP video signal to the display; Second Ethernet physical layer chip: connected to the second fiber optic transceiver, used to receive serial data streams and convert them into parallel data; The second field-programmable gate array (FPGA) is connected to the second Ethernet physical layer chip and is used to unpack the received parallel data, separate the digital audio signal and the downlink control signal of the AUX channel, and pack the keyboard and mouse signal and the uplink control signal of the AUX channel. Digital audio conversion chip: connected to the second field-programmable gate array, converting digital audio signals into analog audio signals; Audio output interface: Connected to the digital audio conversion chip, used to output analog audio; USB-A port: used to connect USB HID devices; and The second microcontroller unit is connected to the USB-A interface to identify and parse data from the connected USB HID device, and then transmits the data back to the transmitter via the second field-programmable gate array, the second Ethernet physical layer chip, and multimode fiber; and configures and controls the second timer via the I2C bus. As a further preferred embodiment of this utility model, the USB audio decoding chip decodes the USB audio data stream into the I2S digital audio format.

[0011] As a further preferred embodiment of this utility model, the USB HID signal includes USB keyboard information and USB mouse signal; the USB HID device includes a USB keyboard and a USB mouse.

[0012] As a further preferred embodiment of this utility model, the analog audio is an L / R channel.

[0013] As a further preferred embodiment of this utility model, both the first field-programmable gate array (FPGA) and the second FPGA are domestically produced Gowin FPGAs.

[0014] As a further preferred embodiment of this utility model, both the transmitter and the receiver are independently powered by an external power adapter.

[0015] As a further preferred embodiment of this utility model, the transmitter is connected to the computer host and the receiver is connected to the user terminal.

[0016] The fiber optic-based KVM extender of this invention, by adopting the above technical solution, can achieve the following beneficial effects: 1. Ultra-long transmission distance and high bandwidth: Using multimode fiber as the transmission medium, combined with a signal processing capability of 8.1Gbps per channel, it can stably transmit DP 1.4 high bandwidth signals for more than 300 meters, perfectly supporting lossless video specifications such as 4K@144Hz and 8K@60Hz.

[0017] 2. High fidelity and strong anti-interference: The high-performance retimer ensures the integrity of the high-speed DP signal after long-distance transmission, and the fiber optic transmission is inherently resistant to electromagnetic interference, ensuring stable operation in complex electromagnetic environments.

[0018] 3. Excellent USB compatibility: The receiver's second microcontroller acts as the USB host, while the transmitter's first microcontroller simulates dual USB devices, achieving broad compatibility with various keyboards and mice. No additional drivers are required; it is plug-and-play and solves the problem of unstable USB device recognition in traditional solutions.

[0019] 4. High Integration and Flexibility: The FPGA efficiently packages and processes non-video signals (audio, keyboard / mouse, AUX), and combines this with an Ethernet PHY as the physical layer transmission scheme, enabling multiple signals to be multiplexed and transmitted on the same optical fiber. The programmability of the FPGA also allows for future functional expansion (such as infrared control, RS232, etc.).

[0020] 5. Low latency and stable bidirectional communication: Short signal processing path and hardware-level processing ensure extremely low end-to-end transmission latency. Utilizing DP's AUX channel and a custom data packet channel, a stable bidirectional communication link is established, fully supporting DisplayPort core functions such as EDID reading and HPD (hot-plug detection). Attached Figure Description

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0022] Figure 1 This is a schematic diagram of an embodiment of the KVM extender based on fiber optic transmission provided by this utility model.

[0023] The purpose, features, and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Terms such as "upper," "lower," "left," "right," "middle," and "one" used in the preferred embodiments are merely for clarity of description and are not intended to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of implementation of the present invention.

[0025] like Figure 1 As shown, this utility model provides a transmitter connected to a computer host and a receiver connected to a user end, wherein the transmitter and receiver are connected via a multimode optical fiber; wherein, The transmitter includes: Video input interface (DP In): Used to receive DP video signals (also known as DisplayPort video signals) from the computer host. First timer: Electrically connected to the video input interface, used to perform signal shaping and clock recovery on the input DP video signal (e.g., DP1.4 HBR3 high bandwidth video signal) to enhance the signal's driving capability and integrity; USB-B interface: Used to connect to a computer host to transmit USB data streams; USB hub: Connected to the USB-B interface, it is used to expand multiple downstream ports to connect multiple USB devices simultaneously, such as connecting USB audio devices and USB HID devices (e.g., keyboards and mice) to the downstream ports, thereby realizing the aggregation and splitting of data streams from multiple devices; USB audio decoding chip: connected to the USB hub, used to decode USB audio signals into digital audio format; The first microcontroller unit (MCU) is used to process USB HID signals and configure and control the first timer via the I2C bus. This first microcontroller unit supports dual USB device functionality and can be simulated as a USB keyboard and a USB mouse device respectively, thereby improving compatibility with different operating systems.

[0026] The first field-programmable gate array (also known as the first FPGA) is connected to the AUX channel of the USB audio decoding chip, the first microcontroller unit, and the first timer, respectively, to package the digital audio signal and the downlink control signal of the AUX channel, and to separate the USB HID data (such as keyboard and mouse data) and the uplink control signal of the AUX channel. First Ethernet physical layer chip: connected to the first field-programmable gate array (FPGA), used to convert the packetized data signal into a serial data stream suitable for fiber optic transmission; and The first fiber optic transceiver includes a fiber optic transmitter, which is connected to the first timer and the first Ethernet physical layer chip respectively, to combine the processed DP video signal and serial data stream into the same multimode fiber for transmission via photoelectric conversion; the signal bandwidth processed by the photoelectric conversion is 8.1G per channel, supporting 4K@144Hz video signal transmission.

[0027] The receiver includes: Second fiber optic transceiver: includes a fiber optic receiver for receiving optical signals from multimode fiber and converting them into electrical signals, separating DP video signals and serial data streams; The second timer is connected to the second fiber optic transceiver and is used to perform clock recovery and signal shaping on the recovered DP video signal again to ensure the stability of the output signal. Video output interface: connected to the second timer, used to output the restored DP video signal to the display; Second Ethernet physical layer chip: connected to the second fiber optic transceiver, used to receive serial data streams and convert them into parallel data; The second field-programmable gate array (also known as the second FPGA) is connected to the second Ethernet physical layer chip and is used to unpack the received parallel data, separate the digital audio signal and the downlink control signal of the AUX channel, and pack the keyboard and mouse signal and the uplink control signal of the AUX channel. Digital audio conversion chip: connected to the second field-programmable gate array, converting digital audio signals into analog audio signals; Audio output interface (DP Out): Connected to the digital audio conversion chip, used to output analog audio; USB-A port: used to connect USB HID devices; and The second microcontroller unit (USB MCU) is connected to the USB-A interface to identify and parse data from the connected USB HID device, and then transmits it back to the transmitter via the second field-programmable gate array, the second Ethernet physical layer chip, and multimode fiber; and configures and controls the second timer via the I2C bus. In one specific implementation, the USB audio decoding chip decodes the USB audio data stream into an I2S digital audio format. The USB HID signal includes USB keyboard information and USB mouse signals; the USB HID device includes a USB keyboard and a USB mouse.

[0028] In another specific implementation, the analog audio is in L / R channels, the transmitter is connected to the computer host, and the receiver is connected to the user terminal. Both the transmitter and receiver are independently powered by external power adapters, allowing them to operate more independently and without interfering with each other.

[0029] Preferably, both the first and second field-programmable gate arrays use domestically produced Gowin FPGAs, which can optimize cost and supply chain security while ensuring performance.

[0030] To enable those skilled in the art to fully understand and implement the technical solution of this utility model, the working principle of the transmitter and receiver will be described in detail below.

[0031] The transmitter works as follows: 1. Video signal path: The DP 1.4 video signal output from the computer host enters the transmitter through the DP In interface. The signal is first sent to the first timer, which equalizes and restores the clock, eliminating signal jitter and attenuation caused by PC output or PCB traces. Then, a DP stream with higher signal quality that has been redriven and shaped is output. This video stream is directly sent to the first fiber optic transceiver.

[0032] 2. USB Audio Signal Path: The computer host outputs a USB data stream to the USB hub via the USB-B interface. The USB hub separates the data stream, one of which is the USB audio data, and sends it to the USB audio decoding chip. This chip decodes the USB audio packets into the standard I2S digital audio format and sends it to the first FPGA.

[0033] 3. USB keyboard and mouse signal path: The MCU communicates with the first FPGA through the UART interface to obtain the separated USB HID (keyboard / mouse) data; the MCU then simulates two independent USB HID devices and connects them to the USB hub, and the USB hub gathers the USB HID signals and transmits them to the computer through the USB-B interface.

[0034] 4. Control and Data Packaging: The first FPGA is the core of the transmitter's data processing. It receives I2S audio from the USB audio decoding chip and control information (such as DPCD status) exchanged with the first timer via the AUX channel. The first FPGA packages this data from different sources and at different rates into a unified data frame. It also separates the USB HID data and the AUX channel uplink data (such as EDID, HPD status, etc.). 5. Fiber Optic Transmission: The packaged data frames are sent to the first Ethernet physical layer chip, which converts them into high-speed serial differential signals. Finally, the fiber optic transmitter combines the two signals: one is the original high-speed DP video stream from the first timer, and the other is the serial data stream from the first Ethernet physical layer chip. Through photoelectric conversion, these two signals are modulated onto light and transmitted through a single multimode fiber.

[0035] The receiver's workflow is as follows: 1. Fiber Optic Reception: After receiving the optical signal, the second fiber optic transceiver demultiplexes it into two electrical signals: one is a DP video stream and the other is a serial data stream.

[0036] 2. Video Signal Restoration Path: The received DP video stream is fed into a second timer. Similar to the transmitter, the second timer performs clock recovery and signal shaping on the signal after long-distance fiber optic transmission to compensate for losses and dispersion caused by fiber optic transmission. The restored high-quality DP signal is output to the display through the DP Out interface.

[0037] 3. Data Unpacking and Distribution: The serial data stream is sent to the second Ethernet physical layer chip, which converts it into parallel data frames and sends them to the second FPGA. The second FPGA performs the opposite operation to the first FPGA, separating the I2S digital audio and AUX channel downlink control information, and packaging the keyboard and mouse data and AUX channel uplink status information.

[0038] 4. Audio output path: The separated I2S digital audio signal is sent to a digital audio converter chip, which converts it into an analog L / R stereo audio signal and provides it to headphones or speakers through the audio output interface.

[0039] 5. Keyboard and Mouse Signal Feedback Path: Users operate the device via a keyboard and mouse connected to the USB-A interface. The USBMCU, acting as the USB Host, actively enumerates and parses the HID reports of these peripherals and transmits them via UAR. T The data is then sent back to the second FPGA. The second FPGA packages the returned data and, via the second Ethernet physical layer chip and the second fiber optic transceiver, transmits it back to the transmitter through fiber optic cable, ultimately reaching the computer host, thus completing a full two-way interaction.

[0040] The KVM extender based on fiber optic transmission in this embodiment enables bidirectional, long-distance, high-fidelity transmission of video, audio, and USB HID signals over a single fiber optic cable.

[0041] Although specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. A KVM extender based on fiber optic transmission, characterized in that, It includes a transmitter and a receiver, which are connected via a multimode optical fiber; wherein, The transmitter includes: Video input interface: used to receive DP video signals from the computer host; First timer: Electrically connected to the video input interface, used to perform signal shaping and clock recovery on the input DP video signal to enhance the signal's driving capability and integrity; USB-B interface: Used to connect to a computer host to transmit USB data streams; USB hub: Connected to the USB-B interface, it is used to expand multiple downstream ports to connect multiple USB devices simultaneously, realizing the aggregation and splitting of data streams from multiple devices; USB audio decoding chip: connected to the USB hub, used to decode USB audio signals into digital audio format; First microcontroller unit: used to process USB HID signals and configure and control the first timer via the I2C bus; The first field-programmable gate array is connected to the AUX channel of the USB audio decoding chip, the first microcontroller unit, and the first timer, respectively, to package the digital audio signal and the downlink control signal of the AUX channel, and to separate the USBHID data and the uplink control signal of the AUX channel. First Ethernet physical layer chip: connected to the first field-programmable gate array (FPGA), used to convert the packetized data signal into a serial data stream suitable for fiber optic transmission; and First fiber optic transceiver: includes a fiber optic transmitter, which is connected to the first timer and the first Ethernet physical layer chip respectively, so as to combine the processed DP video signal and serial data stream into the same multimode fiber for transmission through photoelectric conversion; The receiver includes: Second fiber optic transceiver: includes a fiber optic receiver for receiving optical signals from multimode fiber and converting them into electrical signals, separating DP video signals and serial data streams; The second timer is connected to the second fiber optic transceiver and is used to perform clock recovery and signal shaping on the recovered DP video signal again to ensure the stability of the output signal. Video output interface: connected to the second timer, used to output the restored DP video signal to the display; Second Ethernet physical layer chip: connected to the second fiber optic transceiver, used to receive serial data streams and convert them into parallel data; The second field-programmable gate array (FPGA) is connected to the second Ethernet physical layer chip and is used to unpack the received parallel data, separate the digital audio signal and the downlink control signal of the AUX channel, and pack the keyboard and mouse signal and the uplink control signal of the AUX channel. Digital audio conversion chip: connected to the second field-programmable gate array, converting digital audio signals into analog audio signals; Audio output interface: Connected to the digital audio conversion chip, used to output analog audio; USB-A port: used to connect USB HID devices; and The second microcontroller unit is connected to the USB-A interface to identify and parse the data of the connected USB HID device, and then transmits it back to the transmitter via the second field-programmable gate array, the second Ethernet physical layer chip, and the multimode fiber; and configures and controls the second timer via the I2C bus.

2. The KVM extender based on fiber optic transmission according to claim 1, characterized in that: The USB audio decoding chip decodes the USB audio data stream into the I2S digital audio format.

3. The KVM extender based on fiber optic transmission according to claim 1, characterized in that: The USB HID signal includes USB keyboard information and USB mouse signal; the USB HID device includes a USB keyboard and a USB mouse.

4. The KVM extender based on fiber optic transmission according to claim 1, characterized in that: The simulated audio is in L / R channels.

5. The KVM extender based on fiber optic transmission according to claim 1, characterized in that: Both the first and second field-programmable gate arrays use domestically produced Gowin FPGAs.

6. The KVM extender based on fiber optic transmission according to claim 1, characterized in that: Both the transmitter and receiver are independently powered by an external power adapter.

7. The KVM extender based on fiber optic transmission according to any one of claims 1 to 6, characterized in that: The transmitter is connected to the computer host, and the receiver is connected to the user terminal.

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