Signal extension device, USB optical fiber extender and method

Abstract

The invention discloses a signal extension device, a USB optical fiber extender and a method, and relates to the technical field of data transmission, the signal extension device comprises a USB protocol identification module, a processing module and a first output module which are electrically connected in sequence; the first signal extension device is electrically connected with the transmitting equipment; the USB protocol identification module is used for distinguishing a protocol version of a USB signal sent to the first signal extension device by the sending equipment; the processing module is used for processing the USB signals of different protocol versions and forwarding the USB signals to the first output module; and the first output module is used for transmitting the USB signal processed by the processing module to the second signal extension device through the optical fiber channel, and the second signal extension device carries out signal separation and signal conversion on the USB signal transmitted through the optical fiber channel to obtain a USB signal and transmits the USB signal to receiving equipment. According to the invention, the stability and transmission efficiency of the USB signal through the optical fiber extension link are improved.

Description

Technical Field

[0001] The present application relates to the field of data transmission technology, and in particular to a signal extension device, a USB optical fiber extender, and a USB signal extension method. Background Art

[0002] The Universal Serial Bus (USB), as a mainstream data transmission interface, is widely used in industrial control, medical equipment, digital security, and other scenarios. However, due to the electrical characteristics of the USB protocol specification, the reliable transmission distance of USB 2.0 signals through a standard USB cable is generally no more than 5 meters, and the reliable transmission distance of USB 3.x signals through a standard USB cable is generally no more than 3 meters. To meet long-distance transmission requirements, traditional solutions use copper cable extension combined with multi-stage signal relay enhancement devices: USB hubs or dedicated signal amplifiers are connected in series in the transmission path to compensate for signal attenuation. However, this solution has significant drawbacks: each stage of signal relay enhancement equipment can only extend the transmission distance to a limited extent, and the accumulated signal jitter and delay after cascading increase dramatically, resulting in degraded high-speed USB signal transmission stability and increased bit error rates.

[0003] To address these issues, fiber optic transmission technology has been introduced into the USB extension field. For example, patent document CN110955622A proposes a data transmission device and a USB fiber optic extender. These devices connect a first data transmission device to a second data transmission device via optical fiber, transmitting data signals from a host device connected to the first data transmission device to a terminal device connected to the second data transmission device, thereby enabling long-distance USB data transmission.

[0004] This solution breaks through the transmission distance limitation of copper cables, but still has obvious shortcomings: the patent document's data forwarding module uniformly processes all USB signals (including USB 2.0 / 3.0 / 3.1 / 3.2). This mixed processing can easily cause high-speed USB3.x signals to be forced to go through unnecessary data encapsulation / decapsulation processes, increasing protocol conversion delay and low transmission efficiency. Summary of the Invention

[0005] The main purpose of this application is to provide a signal extension device, a USB optical fiber extender and a USB signal extension method, aiming to solve the technical problem of low transmission efficiency of existing USB extension devices using optical fiber technology.

[0006] To achieve the above-mentioned purpose, the present application proposes a first signal extension device, which includes: a USB protocol identification module, a processing module and a first output module electrically connected in sequence; the first signal extension device is electrically connected to a sending device; the USB protocol identification module is used to distinguish the protocol version of the USB signal sent by the sending device to the first signal extension device; the processing module is used to process USB signals of different protocol versions and forward them to the first output module; the first output module is used to transmit the USB signal processed by the processing module to a second signal extension device through an optical fiber channel, and the second signal extension device performs signal separation and signal conversion on the USB signal transmitted through the optical fiber channel to obtain a USB signal and transmit the USB signal to a receiving device.

[0007] In one embodiment, the processing module includes a first processing module and a second processing module; the first processing module is configured to convert a USB 2.0 signal identified by the USB protocol identification module into a serial differential electrical signal and then generate a first optical signal based on the serial differential electrical signal; the second processing module is configured to generate a second optical signal based on a USB 3.x signal identified by the USB protocol identification module, wherein the USB 3.x signal includes a USB 3.0 signal, a USB 3.1 signal, and a USB 3.2 signal.

[0008] In one embodiment, the first processing module includes a first signal enhancement unit, a first codec unit, and a first photoelectric conversion unit; the USB 2.0 signal is transmitted to the first signal enhancement unit to enhance the USB 2.0 signal; the first codec unit converts the enhanced USB 2.0 signal into a serial differential electrical signal; and the first photoelectric conversion unit generates a first optical signal based on the serial differential electrical signal.

[0009] In one embodiment, the USB protocol identification module includes a device identification parsing unit and a rate detection unit. The device identification parsing unit is used to identify USB2.0 signals through the target feature field in the USB descriptor carried by the sending device port; and the rate detection unit is used to identify USB 3.x signals based on the signal transmission rate of the TX and RX differential pairs of the sending device port.

[0010] In addition, to achieve the above-mentioned purpose, the present application also proposes a second signal extension device, which includes: a signal separation module, a signal conversion module and a second output module electrically connected in sequence; the signal separation module is used to distinguish the optical signals input from the first signal extension device to the second signal extension device through the optical fiber channel; the signal conversion module is used to restore the different types of optical signals distinguished by the signal separation module into USB signals; the second output module is connected to the receiving device, and is used to transmit the restored USB signal to the receiving device.

[0011] In one embodiment, the signal conversion module includes a first signal conversion module and a second signal conversion module; the first signal conversion module is used to restore the first optical signal to a USB 2.0 signal, wherein the first optical signal is obtained by the first processing module in the first signal extension device converting the USB 2.0 signal into a serial differential electrical signal based on the photoelectric conversion of the serial differential electrical signal; the second signal conversion module is used to restore the second optical signal to a USB 3.x signal, wherein the second optical signal is obtained by the second processing module in the first signal extension device converting the USB 3.x signal into a USB 3.x signal.

[0012] In one embodiment, the first signal conversion module includes a second photoelectric conversion unit, a second encoding and decoding unit, and a second signal enhancement unit electrically connected in sequence; the second photoelectric conversion unit is used to convert the first optical signal into a serial differential electrical signal; the second encoding and decoding unit is used to decode the serial differential electrical signal into a USB 2.0 signal; and the second signal enhancement unit is used to transmit the decoded USB 2.0 signal to a receiving device through the second output module.

[0013] In addition, to achieve the above-mentioned purpose, the present application also proposes a USB fiber optic extender, which includes: a first signal extension device as described above, and a second signal extension device as described above; the first signal extension device and the second signal extension device are communicatively connected through optical fiber to construct an optical fiber channel to transmit the first optical signal or the second optical signal.

[0014] In addition, to achieve the above-mentioned purpose, the present application also proposes a USB signal extension method, which is applied to a first signal extension device, comprising: identifying a USB signal input from a receiving device; If the USB signal is a USB 2.0 signal, amplifying the USB 2.0 signal and converting the amplified USB 2.0 signal into a serial differential electrical signal, and generating a first optical signal based on the serial differential electrical signal; if the USB signal is a USB 3.x signal, generating a second optical signal based on the USB 3.x signal; The first optical signal or the second optical signal is transmitted to a second signal extension device through an optical fiber channel.

[0015] In one embodiment, the second signal extension device includes: distinguishing the optical signal received from the first signal extension device; If the optical signal is a first optical signal, converting the first optical signal into a serial differential electrical signal, decoding the serial differential electrical signal into a USB 2.0 signal, and transmitting the USB 2.0 signal to a receiving device; If the optical signal is the second optical signal, the second optical signal is restored to a USB 3.x signal, and the USB 3.x signal is transmitted to a receiving device.

[0016] One or more technical solutions proposed in this application have at least the following technical effects: Because existing fiber optic extension solutions use a unified encapsulation / decapsulation process for USB 2.0 and USB 3.x signals, high-speed USB 3.x signals are forced to undergo high-latency conversion, ultimately resulting in low USB signal transmission efficiency.

[0017] This application uses a USB protocol identification module to distinguish the protocols of input signals. Through the first and second processing modules in the processing module, differentiated processing is performed on different input signals. Specifically, USB 2.0 signals are enhanced, converted into serial differential electrical signals, and then a first optical signal is generated; USB 3.x signals are directly generated as second optical signals. Furthermore, when restoring optical signals to USB signals, differentiated processing is also performed on different optical signals. When restoring USB 2.0 signals, photoelectric conversion, encoding and decoding, and signal enhancement are required, while when restoring USB 3.x signals, the second optical signal is directly converted into a USB 3.x signal. Multi-level processing is performed on low-speed USB 2.0 signals to ensure signal quality and solve the problem of low-speed USB signals attenuating and degrading with distance. Direct processing of high-speed USB 3.x signals can avoid encapsulation and decapsulation delays and reduce latency.

[0018] This differentiated processing of different USB signals solves the technical problems of excessive high-speed USB signal delay and low-speed USB signal attenuation caused by unified processing, and improves the stability and transmission efficiency of USB signals through optical fiber extension links. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0021] Figure 1 This is a schematic diagram of the first signal extension device of the present application; Figure 2 This is a schematic diagram of a processing module in the first signal extension device of the present application; Figure 3 This is a schematic diagram of the second signal extension device of the present application; Figure 4 Schematic diagram of the USB fiber optic extender for this application; Figure 5 This is a schematic diagram of the chip and signal transmission involved in the USB fiber optic extender of this application.

[0022] The purpose, features and advantages of this application will be further explained with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0023] It should be understood that the specific embodiments described herein are merely used to explain the technical solutions of the present application and are not intended to limit the present application.

[0024] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0025] It's important to note that USB 3.x signals can be directly converted from optical to electrical without requiring protocol layer processing because they utilize an independent, full-duplex, high-speed serial differential architecture (e.g., SSTX / SSRX). This architecture includes built-in link and adaptive equalization technologies, dynamically compensating for channel loss. Its signal format is optimized for Gbps-class, long-distance transmission and is highly compatible with the serial modulation characteristics of optical modules. Directly converting USB 3.x signals from optical to electrical preserves the integrity of the original protocol while avoiding the latency, signal jitter, and compatibility risks associated with conversion. Modern optoelectronic devices are capable of supporting USB 3.x's high speeds, such as 20 Gbps. Combined with the interference-resistant and low-loss properties of optical fiber, this allows for lossless transmission over long distances.

[0026] Conversely, due to its half-duplex parallel architecture, embedded clock mechanism, and weak anti-interference characteristics, direct optical-to-electrical conversion of USB 2.0 signals cannot resolve clock desynchronization and signal attenuation issues over long distances. Reconstructing them into high-speed serial differential signals through SerDes protocol conversion not only embeds reliable clock synchronization but also improves noise immunity. This enables low-speed signals (480Mbps), previously limited to 5-meter copper cables, to be stably transmitted over hundreds or even kilometers of optical fiber.

[0027] USB2.0 signals have low latency requirements, while USB3.x models have high latency requirements. Signals have transmission delays in optical fibers, and the longer the optical fiber, the greater the delay. Since the latency required by the USB2.0 signal protocol specification is lower than that required by USB3.x signals, USB2.0 signals can be transmitted over a longer distance, for example, up to 5km, while the extended distance of USB3.0 is only 250m-300m. Based on the differences between the two signals, the technical solution of this application processes USB2.0 signals and USB3.x signals separately. Specifically, two optical fibers can be used to transmit USB signals on the USB fiber optic extender product, one for USB2.0 signals and one for USB3.x signals. This separate transmission can more flexibly adapt to actual application scenarios. When longer distance transmission is required, USB2.0 signals can be used, while USB3.x signals can be used in scenarios with high speed requirements.

[0028] The essence of this differentiated processing is to maximize performance at the lowest cost, avoiding excessive processing of high-speed signals while accurately repairing low-speed signals.

[0029] Existing technical solutions don't generally use optical-to-electrical conversion to extend USB 3.x signals. This is because low-speed devices predominated in the early days, so USB extension solutions tended to extend USB 2.0 signals. However, with the widespread adoption of USB 3.x, when compatibility with multiple USB protocols is required, FPGAs (field programmable gate arrays) are used to uniformly process high- and low-speed signals. This technical solution reduces development complexity by processing two USB signals of different speeds within the same clock domain, sacrificing performance for compatibility. Compared to the prior art, the technical solution of this application directly converts USB 3.x signals into optical-electrical signals, omitting the data encapsulation and decapsulation processes. This reduction in steps can achieve unexpected results, replacing protocol layer intermediaries with direct pass-through. While reducing complexity, it unexpectedly activates the inherent anti-interference potential of high-speed signals. Specifically, high-speed USB 3.x signals bypass the complex encapsulation / decapsulation processes in FPGAs, eliminating the risk of device handshake timeouts caused by protocol conversion. Direct optical-electrical conversion fully preserves the USB 3.x link sequence and adaptive equalization instructions, allowing the receiving device to dynamically adjust equalization parameters. In contrast, the unified processing solution destroys the original code pattern due to encapsulation, resulting in an increased bit error rate.

[0030] However, the technical solution of uniformly processing high-speed and low-speed signals easily causes high-speed USB 3.x signals to be forced to go through unnecessary data encapsulation and decapsulation processes, increasing protocol conversion delay and reducing transmission efficiency.

[0031] It should be noted that the implementation of this embodiment can be a USB fiber optic extender, which consists of a first signal extension device and a second signal extension device. These two devices must be used in conjunction to extend USB signals. This embodiment and the following embodiments will be described using a USB fiber optic extender (referred to as the fiber optic extender) as an example.

[0032] Based on this, the embodiment of the present application provides a first signal extension device, referring to Figure 1 , Figure 1 This is a schematic diagram of the first signal extension device of the present application.

[0033] In this embodiment, the first signal extension device includes: a USB protocol identification module, a processing module and a first output module electrically connected in sequence; the first signal extension device is electrically connected to a sending device; the USB protocol identification module is used to distinguish the protocol version of the USB signal sent by the sending device to the first signal extension device; the processing module is used to process USB signals of different protocol versions and forward them to the first output module; the first output module is used to transmit the USB signal processed by the processing module to the second signal extension device through an optical fiber channel, and the second signal extension device performs signal separation and signal conversion on the USB signal transmitted through the optical fiber channel to obtain a USB signal and transmit the USB signal to the receiving device.

[0034] It should be noted that the first signal extension device described in this embodiment is the transmitting end of the USB optical fiber extender. Its core function is to receive USB signals from a sending device (such as a personal computer, server, industrial control host, camera or other device with a USB interface) and transmit them over long distances through optical fiber (such as single-mode optical fiber or multi-mode optical fiber).

[0035] The first signal extension device comprises three modules, each electrically connected to the other. The USB protocol identification module distinguishes the protocol version of the USB signal received from the transmitting device (e.g., the common USB 2.0, USB 3.0, USB 3.1 / 3.2 Gen 1, or Gen 2). The identified USB signals of different protocols are sent to the processing module, which processes the USB signals. This typically involves converting the electrical signals into optical signals (photoelectric conversion), involving protocol adaptation, signal shaping, or enhancement to ensure that the USB signals are suitable for long-distance, high-speed, and low-loss transmission over optical fiber. Finally, the converted and optimized signals from the processing module are output by the first output module and transmitted via an optical fiber channel (which can be single-mode fiber for ultra-long-distance transmission, such as 5 kilometers, or multi-mode fiber for shorter distances, such as 300 meters, but with high bandwidth) to a remote second signal extension device. The second signal extension device then performs signal separation and conversion on the USB signals transmitted via the optical fiber channel to obtain USB signals, which are then transmitted to the receiving device.

[0036] It can be understood that the first signal extension device realizes effective extension of the USB signal by identifying the USB protocol version, converting the electrical signal into an optical signal, and utilizing the optical fiber channel.

[0037] In one embodiment, in the first signal extension device, the processing module includes a first processing module and a second processing module; the first processing module is used to convert the USB 2.0 signal identified by the USB protocol identification module into a serial differential electrical signal and then generate a first optical signal based on the serial differential electrical signal; the second processing module is used to generate a second optical signal from the USB 3.x signal identified by the USB protocol identification module, wherein the USB 3.x signal includes a USB 3.0 signal, a USB 3.1 signal, and a USB 3.2 signal.

[0038] It should be noted that, due to the need to process USB signals of different protocol versions, the processing module includes a first processing module for USB 2.0 signals and a second processing module for USB 3.x signals. When the USB protocol identification module identifies that the transmitting device is transmitting a USB 2.0 signal, the USB 2.0 signal is sent to the first processing module. The first processing module's core task is to convert the parallel USB 2.0 electrical signals into serial differential electrical signals, such as SerDes signals. SerDes signals are high-speed serial differential electrical signals implemented using serializer / deserializer technology. They transmit data by combining multiple low-speed parallel data channels into one or a few high-speed serial links, greatly improving transmission efficiency and anti-interference capabilities. They are particularly suitable for conversion before long-distance transmission. After completing this conversion, the first processing module modulates the serial differential electrical signal to generate a first optical signal (i.e., an optical pulse signal representing the USB 2.0 signal).

[0039] On the other hand, when a USB 3.x signal (USB 3.0 or higher, such as USB 3.1 / 3.2) is detected, it is transmitted to the second processing module. Because USB 3.x signals already use a high-speed differential signaling design, the second processing module generally does not need to perform the complex protocol layer conversion required for USB 2.0. The second processing module's main function is to directly convert the native high-speed USB 3.x differential electrical signal into optical and electrical signals (or perform necessary optical modulation) to generate the corresponding second optical signal (i.e., the optical pulse signal representing USB 3.x SuperSpeed ​​data).

[0040] Ultimately, the first optical signal representing USB 2.0 or the second optical signal representing USB 3.0 is transmitted to the first output module and then transmitted through the optical fiber channel. Both the first and second optical signals are essentially optical carriers that carry the original USB data information. However, because the two optical signals represent USB signals at different speeds, they must be transmitted using different wavelengths and modulation methods, or on different cores / channels of the same optical fiber to distinguish different USB protocol versions and data streams.

[0041] In another embodiment, in the first signal extension device, the first processing module includes a first signal enhancement unit, a first codec unit and a first photoelectric conversion unit; the USB 2.0 signal is transmitted to the first signal enhancement unit to enhance the USB 2.0 signal; the signal-enhanced USB 2.0 signal is converted into a serial differential electrical signal by the first codec unit; and the first photoelectric conversion unit generates a first optical signal based on the serial differential electrical signal.

[0042] It should be noted that the USB 2.0 signal is transmitted to the first processing module through the hub unit. The hub unit is an internal USB 2.0 hub controller. Exemplarily, the hub controller can be a USB HUB hub composed of a GL852 chip. The function of the hub unit is to connect and receive the USB 2.0 electrical signal from the USB protocol identification module, and perform preliminary signal relay and path allocation to ensure that the signal stably enters the subsequent processing link.

[0043] Next, within the first processing module, the USB 2.0 electrical signal is transmitted to the first signal enhancement unit. For example, the first signal enhancement unit can be composed of a CH317L chip. The function of the first signal enhancement unit is to shape and amplify the USB 2.0 signal that may be attenuated or distorted due to cable transmission, and restore the integrity and strength of the signal through signal conditioning technology (such as equalization, de-jittering, and gain adjustment), preparing for the next step of photoelectric conversion.

[0044] The more stable USB 2.0 signal, after signal enhancement, is then fed into the first codec unit, which converts the original parallel USB 2.0 signal protocol, based on differential pairs (D+ / D-), into a high-speed serial differential electrical signal using the SerDes protocol. For example, the first codec unit can be comprised of an RTL8211FS chip. Finally, the high-speed serial electrical signal, after SerDes protocol conversion, is passed to the first optical-to-electrical conversion unit. For example, the core components of the first optical-to-electrical conversion unit are a laser driver (LDD) and a laser diode (LD). This unit modulates the serial differential electrical signal representing the USB 2.0 signal onto a laser beam, generating a first optical signal (a train of optical pulses) carrying the original USB 2.0 signal. This provides the basis for long-distance, low-loss optical transmission via optical fiber.

[0045] It can be understood that the various units of the first processing module perform signal enhancement, protocol conversion, and optical modulation on the USB 2.0 signal, thereby efficiently and reliably converting the USB 2.0 electrical signal into a first optical signal suitable for optical fiber transmission.

[0046] For example, Figure 2 As shown, Figure 2This is a schematic diagram of the processing module. The processing module includes a first processing module for processing USB 2.0 signals and a second processing module for processing USB 3.x signals. The first processing module further comprises a first signal enhancement unit, a first codec unit, and a first optical-to-electrical conversion unit. The first signal enhancement unit uses signal conditioning technology to restore signal integrity and strength; the first codec unit converts USB 2.0 signals into high-speed serial differential electrical signals using the SerDes protocol; and the first optical-to-electrical conversion unit converts the SerDes-converted high-speed serial electrical signals into a first optical signal carrying the original USB 2.0 signal. The second processing module processes the USB 3.x signals through a USB hub comprised of the GL3590-OV3S1 chip. After performing preliminary signal relay and path allocation, the USB 3.x signals are then subjected to optical-to-electrical conversion to generate a second optical signal carrying the original USB 3.x signal.

[0047] In another embodiment, in the first signal extension device, the USB protocol identification module includes a device identification parsing unit and a rate detection unit. The device identification parsing unit is used to identify the USB 2.0 signal through the target feature field in the USB descriptor carried by the sending device port; the rate detection unit is used to identify the USB 3.x signal based on the signal transmission rate of the TX and RX differential pairs of the sending device port.

[0048] It should be noted that the USB protocol identification module includes a device identification parsing unit and a rate detection unit to distinguish USB signaling versions. The device identification parsing unit operates by reading target characteristic fields, such as the VID or PID fields, in the USB descriptor provided by the transmitting device during the connection handshake phase. USB descriptors are standardized data structures containing fields such as the VID (Vendor ID) and PID (Product ID). These fields are uniquely assigned by the USB Implementers Forum (USB-IF) and can be used to determine the USB signaling protocol version actually used by a USB device. The rate detection unit is used to identify USB 3.x signals (such as USB 3.0, 3.1, and 3.2). It detects whether high-speed signaling activity is present on the TX (Transmit) and RX (Receive) differential pairs at the transmitting device port and measures the actual transmission rate (for example, a high-speed differential signal of ≥5 Gbps is considered a USB 3.x signal). USB 3.x introduces independent SuperSpeed ​​transmit and receive differential signal pairs, whose speeds (such as 5Gbps, 10Gbps, 20Gbps) are much higher than the 480Mbps of USB 2.0.

[0049] In this embodiment, a first signal extension device is provided. It is directly connected to a transmitting device via a USB protocol identification module. A device identification resolution unit reads the VID / PID fields in the USB descriptor for USB 2.0 signals, and a rate detection unit monitors the signal rate of the TX / RX differential pair to identify USB 3.x signals. After distinguishing the protocol version, the USB signal is diverted to a processing module. If it is a USB 2.0 signal, it is processed by the first processing module. The USB 2.0 signal is first distributed through a hub unit for stable routing. A first signal enhancement unit then shapes and amplifies any attenuated or distorted signal. A first codec unit then converts the enhanced parallel USB 2.0 signal into a high-speed serial signal with enhanced interference resistance. Finally, a first optoelectronic conversion unit modulates the signal to generate a first optical signal. If it is a USB 3.x signal, a second processing module directly converts the USB 3.x signal through optoelectronic conversion to generate a second optical signal. Both optical signals are ultimately transmitted to a remote end via a first output module via a fiber optic channel.

[0050] Through dual-path differentiated processing, specifically, USB 3.x signals utilize direct optical-to-electrical conversion, eliminating the need for protocol conversion, simplifying the processing link and reducing latency, while USB 2.0 signals undergo SerDes protocol conversion. This preserves the integrity of the native high-speed USB 3.x signal and avoids redundant conversion losses, while also providing signal enhancement and optical-to-electrical conversion for USB 2.0 signals, significantly improving immunity to electromagnetic interference. This enables both types of signals to achieve stable transmission over ultra-long distances of hundreds of meters over optical fiber, far exceeding the 5-meter limit of USB copper cables. Furthermore, the USB protocol identification module combines descriptor parsing with physical layer rate detection, ensuring broad compatibility from legacy USB 2.0 devices to the latest USB 3.2 devices. The signal enhancement unit, combining pre-processing and encoding / decoding at the transmitter, effectively offsets signal attenuation over long transmission distances, ensuring the timing accuracy of signals received by end devices and reducing communication errors.

[0051] In summary, the first signal extension device, through protocol identification, version-based signal optimization processing and optical fiber transmission, extends the USB connection distance while ensuring the high-speed, stable, low-latency long-distance communication capabilities of multiple generations of devices.

[0052] Based on this, the embodiment of the present application provides a second signal extension device, referring to Figure 3 , Figure 3 This is a schematic diagram of the second signal extension device of the present application.

[0053] In this embodiment, the second signal extension device includes: a signal separation module, a signal conversion module and a second output module electrically connected in sequence; the signal separation module is used to distinguish the optical signal input from the first signal extension device to the second signal extension device through the optical fiber channel; the signal conversion module is connected to the signal separation module, and is used to restore the different types of optical signals distinguished by the signal separation module into USB signals; the second output module is connected to the receiving device, and is used to transmit the restored USB signal to the receiving device.

[0054] It's important to note that the second signal extension device, as the receiving end of the entire USB fiber optic extender, is responsible for receiving optical signals from the fiber optic channel (i.e., the fiber link connecting the first signal extension device, which can be composed of single-mode or multimode fiber) and converting them into the original USB signal for use by the end device. The second signal extension device comprises three modules: a signal separation module, a signal conversion module, and a second output module, all electrically connected in sequence.

[0055] The signal separation module is responsible for identifying and distinguishing the optical signals transmitted through the optical fiber. The optical signal transmitted may be a first optical signal representing a USB 2.0 signal or a second optical signal representing a USB 3.x signal. The signal separation module determines the specific optical signal type by detecting the physical characteristics of the optical signal and routes it appropriately. The separated optical signals are then sent to the signal conversion module. The signal conversion module performs the opposite operation to that of the processing module in the first signal extension device: for the first optical signal representing a USB 2.0 signal, it first performs optical-to-electrical conversion (converting the optical signal back to an electrical signal) and then decodes the high-speed serial signal to convert it back into a USB 2.0 signal. For the second optical signal representing a USB 3.x signal, it directly performs optical-to-electrical conversion to convert the optical signal directly into a high-speed USB 3.x signal.

[0056] Finally, the USB electrical signal, restored by the signal conversion module, is sent to the second output module. This second output module is essentially a physical USB port (such as Type-A, Type-B, or Type-C), directly connected to the final receiving device (i.e., the target device that needs to use the USB signal, such as a monitor, printer, storage device, data acquisition card, keyboard, mouse, or any terminal device requiring a USB connection). The second output module is responsible for stably and reliably transmitting the restored USB electrical signal to this receiving device, thus completing the entire USB signal transmission process from the sending device to the receiving device, through electrical-to-optical-to-electrical conversion and optical fiber extension.

[0057] It is understandable that the second signal extension device separates the optical signal, reversely converts it to restore the USB electrical signal, and outputs it through the USB interface, ultimately making the remote receiving device feel as if it is directly connected to the sending device.

[0058] In one embodiment, in the second signal extension device, the signal conversion module includes a first signal conversion module and a second signal conversion module; the first signal conversion module is used to restore the first optical signal to a USB 2.0 signal, wherein the first optical signal is obtained by converting the USB 2.0 signal into a serial differential electrical signal by the first processing module in the first signal extension device based on photoelectric conversion of the serial differential electrical signal; the second signal conversion module is used to restore the second optical signal to a USB 3.x signal, wherein the second optical signal is obtained by converting the USB 3.x signal into photoelectric conversion by the second processing module in the first signal extension device.

[0059] It should be noted that within the signal conversion module of the second signal extension device, the work is divided into two sub-modules according to the different optical signals received from the optical fiber channel: the first signal conversion module is responsible for processing the first optical signal representing the USB 2.0 signal. First, the optical signal is converted into a serial differential electrical signal through a photodetector. Then, the serial differential electrical signal is reversely restored to a USB 2.0 signal using a codec unit, completing the conversion from the optical signal to the USB 2.0 electrical signal; the second signal conversion module is responsible for processing the second optical signal representing the USB 3.x signal (such as USB 3.0, 3.1, and 3.2).

[0060] Ultimately, both the USB 2.0 signal restored by the first signal conversion module and the USB 3.x signal restored by the second signal conversion module are sent to the second output module for use by the receiving device. It can be understood that these two submodules perform reverse processing on different optical signals, restoring them to the USB electrical signal format that the receiving device can recognize.

[0061] In another embodiment, in the second signal extension device, the first signal conversion module includes a second photoelectric conversion unit, a second encoding and decoding unit and a second signal enhancement unit electrically connected in sequence; the second photoelectric conversion unit is used to convert the first optical signal into a serial differential electrical signal; the second encoding and decoding unit is used to decode the serial differential electrical signal into a USB2.0 signal; and the second signal enhancement unit is used to transmit the decoded USB 2.0 signal to a receiving device through the second output module.

[0062] It should be noted that the first signal conversion module of the second signal extension device contains three units: a second optical-to-electrical conversion unit, a second codec unit, and a second signal enhancement unit. First, the second optical-to-electrical conversion unit converts the received first optical signal back into a serial differential electrical signal, completing the optical-to-electrical conversion. Next, the serial differential electrical signal, such as a SerDes (SerDes) signal, is fed into the second codec unit. The core of the second codec unit is a SerDes deserializer, which performs the opposite operation of the transmitting codec unit, decoding the serial differential electrical signal, such as a SerDes signal, into a USB 2.0 signal. Finally, the decoded USB 2.0 signal may introduce slight distortion due to long-distance transmission (even through optical fiber, attenuation may still occur in the electrical signal segment) or the conversion process. Therefore, it must pass through the second signal enhancement unit, which shapes, amplifies, and enhances the restored USB 2.0 signal to restore its full voltage swing, timing characteristics, and drive capability. After signal enhancement processing, the stable and reliable USB 2.0 signal is passed to the second output module, which transmits the USB 2.0 signal through the second output module and connects it to the receiving device, ensuring that the receiving device can recognize and communicate normally.

[0063] It is understandable that the first signal conversion module restores the first optical signal transmitted from the remote end into a USB 2.0 electrical signal that can be directly used by the receiving device through three steps of photoelectric conversion, decoding and signal enhancement.

[0064] In this embodiment, a second signal extension device is provided. A signal separation module receives optical signals (including a first optical signal representing USB 2.0 and a second optical signal representing USB 3.x) from a fiber optic channel. The signal separation module distinguishes the two optical signals based on their physical characteristics and routes them to corresponding signal conversion modules. The first optical signal is transmitted to the first signal conversion module, where a second optoelectronic conversion unit converts the optical signal into a serial differential electrical signal. A second codec unit then decodes the serial differential electrical signal, such as a SerDes signal, and converts it back into a USB 2.0 signal. Finally, a second signal enhancement unit shapes and amplifies the signal to eliminate residual attenuation associated with long-distance transmission. The second optical signal is transmitted to the second signal conversion module, where it is directly converted into a USB 3.x signal through optoelectronic conversion. Both converted USB electrical signals are ultimately output to a receiving device via a second output module.

[0065] Optical signal separation and independent dual-path processing ensure that both USB 2.0 and USB 3.x signals are losslessly restored to their original electrical specifications. Specifically, USB 2.0 signals are decoded and amplified before output, effectively counteracting potential signal attenuation at the end of the fiber optic link. Direct-through restoration of USB 3.x signals avoids jitter introduced by redundant processing and reduces high-speed signal latency. This enables receiving devices to establish stable handshakes and maintain full-speed communication over long distances, completely breaking the length limitations of USB copper cables and addressing the low transmission efficiency inherent in existing technologies due to the unified processing of two USB signals at different rates.

[0066] Based on this, an embodiment of the present application provides a USB signal extension method. In this embodiment, the USB signal extension method is applied to a first signal extension device, including: identifying a USB signal input from a receiving device; if the USB signal is a USB 2.0 signal, amplifying the USB 2.0 signal, converting the amplified USB 2.0 signal into a serial differential electrical signal, and generating a first optical signal based on the serial differential electrical signal; if the USB signal is a USB 3.x signal, generating a second optical signal based on the USB 3.x signal; and transmitting the first optical signal or the second optical signal to a second signal extension device via an optical fiber channel.

[0067] It should be noted that the first signal extension device first identifies the protocol version of the USB signal input from the transmitting device. If it is a USB 2.0 signal (a low-speed, half-duplex communication signal), it first performs signal amplification on the USB 2.0 signal and then converts the amplified USB 2.0 signal into a serial differential electrical signal (SerDes signal). It then generates a first optical signal based on this serial differential electrical signal. If it is a USB 3.x signal (a high-speed, serial differential architecture), it directly generates a second optical signal based on this USB 3.x signal. Finally, the first or second optical signal is transmitted to the second signal extension device via a fiber optic channel.

[0068] It can be understood that the first signal extension device identifies the USB signal input from the receiving device, enhances and converts the low-speed USB2.0 signal into an optical signal, and directly converts the high-speed USB 3.x signal into an optical signal, and finally transmits it uniformly over long distances through optical fiber.

[0069] In another embodiment, the USB signal extension method, applied to a second signal extension device, includes: distinguishing the optical signal received from the first signal extension device; If the optical signal is the first optical signal, converting the first optical signal into a serial differential electrical signal, decoding the serial differential electrical signal into a USB 2.0 signal, and transmitting the USB 2.0 signal to a receiving device; If the optical signal is the second optical signal, the second optical signal is restored to a USB 3.x signal, and the USB 3.x signal is transmitted to the receiving device.

[0070] It should be noted that the second signal extension device first uses the signal separation module to distinguish the optical signal received from the fiber optic channel and sent by the first signal extension device. If it is identified as the first optical signal, it first performs optical-to-electrical conversion on the first optical signal to convert it into a serial differential electrical signal. Then, it decodes the serial differential electrical signal and reverse-converts it into a USB 2.0 signal. If it is identified as the second optical signal, it directly restores it to a USB 3.x signal. Finally, the restored USB 2.0 or USB 3.x electrical signal is stably transmitted to the receiving device via the physical interface.

[0071] It can be understood that the second extension device distinguishes the optical signals, performs photoelectric conversion and protocol decoding on the first optical signal representing USB 2.0 to restore it, and directly photoelectrically restores the second optical signal representing USB 3.x, and finally transmits the native USB electrical signal to the receiving device.

[0072] For example, in order to help understand the USB fiber optic extender obtained by combining this embodiment with the above embodiments, please refer to Figure 4 , Figure 4 A schematic diagram of a USB fiber optic extender is provided, specifically: The entire USB fiber optic extender is connected to the first signal extension device and the second signal extension device through optical fiber. The first signal extension device is connected to the sending device. The first signal extension device uses the USB protocol identification module to distinguish the USB protocol version sent by the sending device to the first signal extension device, and transmits USB signals of different protocol versions to the processing module to generate optical signals. The generated optical signals are transmitted to the second signal extension device through the first output module via single-mode optical fiber or multi-mode optical fiber.

[0073] The second signal extension device is connected to the receiving device. The second signal extension device separates the optical signal transmitted from the first signal extension device through the single-mode optical fiber or multi-mode optical fiber through the signal separation module (dividing it into a first optical signal representing a USB 2.0 signal and a second optical signal representing a USB 3.x signal), transmits the separated optical signal to the signal conversion module, restores it to a USB signal, and finally sends the restored USB signal to the receiving device through the second output module to achieve USB signal extension.

[0074] For example, Figure 5This is a schematic diagram of the chip and signal transmission involved in the USB fiber optic extender of this application. Both USB 2.0 signals and USB 3.x signals are transmitted in the USB fiber optic extender in the form of paired differential signals. For USB 3.x signals, the transmitting end of the USB extender receives the USB 3.x TX / RX differential signals output by the transmitting device and inputs them into chip one (for example, GL3590-OV3S1) for signal relaying and path allocation. These signals are separated into a transmit direction signal DTX1 and a receive direction signal DRX1 (DTX1 indicates the extender is sending data to the receiving end, and DRX1 indicates the extender is receiving data from the transmitting device). These signals are converted into optical signals by the optoelectronic conversion module and then transmitted via optical fiber to the receiving end of the USB fiber optic extender. The optoelectronic conversion module at the receiving end of the USB fiber optic extender converts the optical signals into DTX1 / DRX1 differential electrical signals, which are input into chip six (for example, GL3590-OV3S1) for signal relaying and path allocation. Ultimately, the USB 3.x TX / RX differential signals are transmitted to the receiving device, enabling long-distance transmission of USB 3.x signals.

[0075] For USB 2.0, the USB extender's transmitting end receives the USB 2.0 signal output by the transmitting device and inputs it into chip two (such as the CH317L) for signal amplification. The signal is then output to chip three (such as the RTL8211FS), which completes protocol parsing and serialization, converting it into a single-channel high-speed serial differential signal DTX2 / DRX2 (DTX2 carries transmit data, and DRX2 carries receive data). This signal is then converted into an optical signal by the optoelectronic conversion module and transmitted via optical fiber to the USB fiber extender's receiving end. The optoelectronic conversion module at the USB fiber extender's receiving end converts the optical signal into DTX2 / DRX2, which is then transmitted to chip four (such as the RTL8211FS) for reverse decoding, restoring the single-channel high-speed serial differential signal to a USB 2.0 signal. This signal is then amplified by chip five (such as the CH317L) and input into chip six (such as the GL3590-OV3S1), enabling long-distance transmission of USB 2.0 signals.

[0076] It should be noted that the above examples are only used to understand the present application and do not constitute a limitation on the USB signal extender of the present application. Based on this technical concept, more forms of simple transformations, such as the interaction and combination of various embodiments, are all within the scope of protection of the present application.

[0077] The above description is only part of the embodiments of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made by using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A first signal extension device, characterized in that: include: A USB protocol identification module, a processing module and a first output module are electrically connected in sequence; the first signal extension device is electrically connected to a sending device; the USB protocol identification module is used to distinguish the protocol version of the USB signal sent by the sending device to the first signal extension device; the processing module is used to process USB signals of different protocol versions and forward them to the first output module; the first output module is used to transmit the USB signal processed by the processing module to the second signal extension device through a fiber optic channel, and the second signal extension device performs signal separation and signal conversion on the USB signal transmitted through the fiber optic channel to obtain a USB signal and transmit the USB signal to a receiving device.

2. The first signal extension device according to claim 1, wherein: The processing module includes a first processing module and a second processing module; the first processing module is configured to convert a USB 2.0 signal identified by the USB protocol identification module into a serial differential electrical signal and then generate a first optical signal based on the serial differential electrical signal; the second processing module is configured to generate a second optical signal based on a USB 3.x signal identified by the USB protocol identification module, wherein the USB 3.x signal includes a USB 3.0 signal, a USB 3.1 signal, and a USB 3.2 signal.

3. The first signal extension device according to claim 2, wherein: The first processing module includes a first signal enhancement unit, a first encoding and decoding unit, and a first photoelectric conversion unit; the USB 2.0 signal is transmitted to the first signal enhancement unit to enhance the USB 2.0 signal; Converting the USB2.0 signal after signal enhancement into a serial differential electrical signal by the first encoding and decoding unit; A first optical signal is generated based on the serial differential electrical signal by the first photoelectric conversion unit.

4. The first signal extension device according to claim 1, wherein: The USB protocol identification module includes a device identification parsing unit and a rate detection unit. The device identification parsing unit is used to identify USB 2.0 signals based on the target feature field in the USB descriptor carried by the sending device port; the rate detection unit is used to identify USB 3.x signals based on the signal transmission rate of the TX and RX differential pairs of the sending device port.

5. A second signal extension device, characterized in that: include: A signal separation module, a signal conversion module and a second output module are electrically connected in sequence; the signal separation module is used to distinguish the optical signals input from the first signal extension device to the second signal extension device through the optical fiber channel; the signal conversion module is used to restore the different types of optical signals distinguished by the signal separation module into USB signals; the second output module is connected to a receiving device and is used to transmit the restored USB signals to the receiving device.

6. The second signal extension device according to claim 5, characterized in that: The signal conversion module includes a first signal conversion module and a second signal conversion module; the first signal conversion module is used to restore the first optical signal to a USB2.0 signal, wherein the first optical signal is obtained by the first processing module in the first signal extension device converting the USB 2.0 signal into a serial differential electrical signal based on the photoelectric conversion of the serial differential electrical signal; the second signal conversion module is used to restore the second optical signal to a USB 3.x signal, wherein the second optical signal is obtained by the second processing module in the first signal extension device converting the USB 3.x signal into a USB 3.x signal.

7. The second signal extension device according to claim 6, wherein: The first signal conversion module includes a second photoelectric conversion unit, a second encoding and decoding unit, and a second signal enhancement unit electrically connected in sequence; the second photoelectric conversion unit is used to convert the first optical signal into a serial differential electrical signal; The second encoding and decoding unit is used to decode the serial differential electrical signal into a USB 2.0 signal; the second signal enhancement unit is used to transmit the decoded USB 2.0 signal to a receiving device through a second output module.

8. A USB optical fiber extender, characterized in that: include: The first signal extension device according to any one of claims 1 to 4; the second signal extension device according to any one of claims 5 to 7; the first signal extension device and the second signal extension device are communicatively connected via an optical fiber to construct an optical fiber channel for transmitting the first optical signal or the second optical signal.

9. A USB signal extension method, characterized in that: Applicable to the first signal extension device, comprising: Identify the USB signal input from the receiving device; If the USB signal is a USB 2.0 signal, amplifying the USB 2.0 signal and converting the amplified USB 2.0 signal into a serial differential electrical signal, and generating a first optical signal based on the serial differential electrical signal; if the USB signal is a USB 3.x signal, generating a second optical signal based on the USB 3.x signal; The first optical signal or the second optical signal is transmitted to a second signal extension device through an optical fiber channel.

10. The method according to claim 9, wherein Applicable to the second signal extension device, including: distinguishing the optical signal received from the first signal extension device; If the optical signal is a first optical signal, converting the first optical signal into a serial differential electrical signal, decoding the serial differential electrical signal into a USB 2.0 signal, and transmitting the USB 2.0 signal to a receiving device; If the optical signal is the second optical signal, the second optical signal is restored to a USB 3.x signal, and the USB 3.x signal is transmitted to a receiving device.

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